start-ver=1.4 cd-journal=joma no-vol=626 cd-vols= no-issue=7999 article-no= start-page=670 end-page=677 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240131 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Oxygen-evolving photosystem II structures during S1?S2?S3 transitions en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem II (PSII) catalyses the oxidation of water through a four-step cycle of Si states (i?=?0?4) at the Mn4CaO5 cluster1,2,3, during which an extra oxygen (O6) is incorporated at the S3 state to form a possible dioxygen4,5,6,7. Structural changes of the metal cluster and its environment during the S-state transitions have been studied on the microsecond timescale. Here we use pump-probe serial femtosecond crystallography to reveal the structural dynamics of PSII from nanoseconds to milliseconds after illumination with one flash (1F) or two flashes (2F). YZ, a tyrosine residue that connects the reaction centre P680 and the Mn4CaO5 cluster, showed structural changes on a nanosecond timescale, as did its surrounding amino acid residues and water molecules, reflecting the fast transfer of electrons and protons after flash illumination. Notably, one water molecule emerged in the vicinity of Glu189 of the D1 subunit of PSII (D1-E189), and was bound to the Ca2+ ion on a sub-microsecond timescale after 2F illumination. This water molecule disappeared later with the concomitant increase of O6, suggesting that it is the origin of O6. We also observed concerted movements of water molecules in the O1, O4 and Cl-1 channels and their surrounding amino acid residues to complete the sequence of electron transfer, proton release and substrate water delivery. These results provide crucial insights into the structural dynamics of PSII during S-state transitions as well as O?O bond formation. en-copyright= kn-copyright= en-aut-name=LiHongjie en-aut-sei=Li en-aut-mei=Hongjie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NangoEriko en-aut-sei=Nango en-aut-mei=Eriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OwadaShigeki en-aut-sei=Owada en-aut-mei=Shigeki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YamadaDaichi en-aut-sei=Yamada en-aut-mei=Daichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=HashimotoKana en-aut-sei=Hashimoto en-aut-mei=Kana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=LuoFangjia en-aut-sei=Luo en-aut-mei=Fangjia kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=TanakaRie en-aut-sei=Tanaka en-aut-mei=Rie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=KangJungmin en-aut-sei=Kang en-aut-mei=Jungmin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=KishiShunpei en-aut-sei=Kishi en-aut-mei=Shunpei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=YuHuaxin en-aut-sei=Yu en-aut-mei=Huaxin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=MatsubaraNaoki en-aut-sei=Matsubara en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=FujiiHajime en-aut-sei=Fujii en-aut-mei=Hajime kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=SugaharaMichihiro en-aut-sei=Sugahara en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=SuzukiMamoru en-aut-sei=Suzuki en-aut-mei=Mamoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=MasudaTetsuya en-aut-sei=Masuda en-aut-mei=Tetsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=KimuraTetsunari en-aut-sei=Kimura en-aut-mei=Tetsunari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= en-aut-name=ThaoTran Nguyen en-aut-sei=Thao en-aut-mei=Tran Nguyen kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=21 ORCID= en-aut-name=YonekuraShinichiro en-aut-sei=Yonekura en-aut-mei=Shinichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=22 ORCID= en-aut-name=YuLong-Jiang en-aut-sei=Yu en-aut-mei=Long-Jiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=23 ORCID= en-aut-name=ToshaTakehiko en-aut-sei=Tosha en-aut-mei=Takehiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=24 ORCID= en-aut-name=TonoKensuke en-aut-sei=Tono en-aut-mei=Kensuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=25 ORCID= en-aut-name=JotiYasumasa en-aut-sei=Joti en-aut-mei=Yasumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=26 ORCID= en-aut-name=HatsuiTakaki en-aut-sei=Hatsui en-aut-mei=Takaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=27 ORCID= en-aut-name=YabashiMakina en-aut-sei=Yabashi en-aut-mei=Makina kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=28 ORCID= en-aut-name=KuboMinoru en-aut-sei=Kubo en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=29 ORCID= en-aut-name=IwataSo en-aut-sei=Iwata en-aut-mei=So kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=30 ORCID= en-aut-name=IsobeHiroshi en-aut-sei=Isobe en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=31 ORCID= en-aut-name=YamaguchiKizashi en-aut-sei=Yamaguchi en-aut-mei=Kizashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=32 ORCID= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=33 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=34 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Institute of Multidisciplinary Research for Advanced Materials, Tohoku University kn-affil= affil-num=4 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=5 en-affil=Department of Picobiology, Graduate School of Life Science, University of Hyogo kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=8 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=11 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=12 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=13 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=14 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=15 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=16 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=17 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=18 en-affil=Institute for Protein Research, Osaka University kn-affil= affil-num=19 en-affil=Division of Food and Nutrition, Faculty of Agriculture, Ryukoku University kn-affil= affil-num=20 en-affil=Department of Chemistry, Graduate School of Science, Kobe University kn-affil= affil-num=21 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=22 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=23 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=24 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=25 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=26 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=27 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=28 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=29 en-affil=Department of Picobiology, Graduate School of Life Science, University of Hyogo kn-affil= affil-num=30 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=31 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=32 en-affil=Center for Quantum Information and Quantum Biology, Osaka University kn-affil= affil-num=33 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=34 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=1 article-no= start-page=8164 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20231209 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural insights into photosystem II supercomplex and trimeric FCP antennae of a centric diatom Cyclotella meneghiniana en-subtitle= kn-subtitle= en-abstract= kn-abstract=Diatoms are dominant marine algae and contribute around a quarter of global primary productivity, the success of which is largely attributed to their photosynthetic capacity aided by specific fucoxanthin chlorophyll-binding proteins (FCPs) to enhance the blue-green light absorption under water. We purified a photosystem II (PSII)-FCPII supercomplex and a trimeric FCP from Cyclotella meneghiniana (Cm) and solved their structures by cryo-electron microscopy (cryo-EM). The structures reveal detailed organizations of monomeric, dimeric and trimeric FCP antennae, as well as distinct assemblies of Lhcx6_1 and dimeric FCPII-H in PSII core. Each Cm-PSII-FCPII monomer contains an Lhcx6_1, an FCP heterodimer and other three FCP monomers, which form an efficient pigment network for harvesting energy. More diadinoxanthins and diatoxanthins are found in FCPs, which may function to quench excess energy. The trimeric FCP contains more chlorophylls c and fucoxanthins. These diversified FCPs and PSII-FCPII provide a structural basis for efficient light energy harvesting, transfer, and dissipation in C. meneghiniana. en-copyright= kn-copyright= en-aut-name=ZhaoSonghao en-aut-sei=Zhao en-aut-mei=Songhao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShenLili en-aut-sei=Shen en-aut-mei=Lili kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=LiXiaoyi en-aut-sei=Li en-aut-mei=Xiaoyi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TaoQiushuang en-aut-sei=Tao en-aut-mei=Qiushuang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=LiZhenhua en-aut-sei=Li en-aut-mei=Zhenhua kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=XuCaizhe en-aut-sei=Xu en-aut-mei=Caizhe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ZhouCuicui en-aut-sei=Zhou en-aut-mei=Cuicui kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=YangYanyan en-aut-sei=Yang en-aut-mei=Yanyan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=SangMin en-aut-sei=Sang en-aut-mei=Min kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=HanGuangye en-aut-sei=Han en-aut-mei=Guangye kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=YuLong-Jiang en-aut-sei=Yu en-aut-mei=Long-Jiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=KuangTingyun en-aut-sei=Kuang en-aut-mei=Tingyun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=WangWenda en-aut-sei=Wang en-aut-mei=Wenda kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= affil-num=1 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=2 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=3 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=5 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=6 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=7 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=8 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=9 en-affil=China National Botanical Garden kn-affil= affil-num=10 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=11 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=12 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=13 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=14 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= END start-ver=1.4 cd-journal=joma no-vol=299 cd-vols= no-issue=7 article-no= start-page=104839 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=202307 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural insights into the action mechanisms of artificial electron acceptors in photosystem II en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem II (PSII) utilizes light energy to split water, and the electrons extracted from water are transferred to QB, a plastoquinone molecule bound to the D1 subunit of PSII. Many artificial electron acceptors (AEAs) with molecular structures similar to that of plastoquinone can accept electrons from PSII. However, the molecular mechanism by which AEAs act on PSII is unclear. Here, we solved the crystal structure of PSII treated with three different AEAs, 2,5-dibromo-1,4-benzoquinone, 2,6dichloro-1,4-benzoquinone, and 2-phenyl-1,4-benzoquinone, at 1.95 to 2.10 angstrom resolution. Our results show that all AEAs substitute for QB and are bound to the QB-binding site (QB site) to receive electrons, but their binding strengths are different, resulting in differences in their efficiencies to accept electrons. The acceptor 2-phenyl-1,4-benzoquinone binds most weakly to the QB site and showed the highest oxygen-evolving activity, implying a reverse relationship between the binding strength and oxygen-evolving activity. In addition, a novel quinonebinding site, designated the QD site, was discovered, which is located in the vicinity of QB site and close to QC site, a binding site reported previously. This QD site is expected to play a role as a channel or a storage site for quinones to be transported to the QB site. These results provide the structural basis for elucidating the actions of AEAs and exchange mechanism of QB in PSII and also provide information for the design of more efficient electron acceptors. en-copyright= kn-copyright= en-aut-name=KamadaShinji en-aut-sei=Kamada en-aut-mei=Shinji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Faculty of Science, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=photosynthesis kn-keyword=photosynthesis en-keyword=electron transfer kn-keyword=electron transfer en-keyword=structural biology kn-keyword=structural biology en-keyword=crystal structure kn-keyword=crystal structure en-keyword=electron acceptor kn-keyword=electron acceptor END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=1 article-no= start-page=920 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230217 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of a monomeric photosystem I core associated with iron-stress-induced-A proteins from Anabaena sp. PCC 7120 en-subtitle= kn-subtitle= en-abstract= kn-abstract=Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions. The cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, their binding property and functional roles in PSI are still missing. We analyzed a cryo-electron microscopy structure of a PSI-IsiA supercomplex isolated from Anabaena grown under an iron-deficient condition. The PSI-IsiA structure contains six IsiA subunits associated with the PsaA side of a PSI core monomer. Three of the six IsiA subunits were identified as IsiA1 and IsiA2. The PSI-IsiA structure lacks a PsaL subunit; instead, a C-terminal domain of IsiA2 occupies the position of PsaL, which inhibits the oligomerization of PSI, leading to the formation of a PSI monomer. Furthermore, excitation-energy transfer from IsiAs to PSI appeared with a time constant of 55 ps. These findings provide insights into both the molecular assembly of the Anabaena IsiA family and the functional roles of IsiAs. en-copyright= kn-copyright= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HamaguchiTasuku en-aut-sei=Hamaguchi en-aut-mei=Tasuku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UenoYoshifumi en-aut-sei=Ueno en-aut-mei=Yoshifumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TsuboshitaNaoki en-aut-sei=Tsuboshita en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ShimizuShota en-aut-sei=Shimizu en-aut-mei=Shota kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=FurutaniMiyu en-aut-sei=Furutani en-aut-mei=Miyu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=EhiraShigeki en-aut-sei=Ehira en-aut-mei=Shigeki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=YonekuraKoji en-aut-sei=Yonekura en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=4 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=5 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=8 en-affil=Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=11 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=12 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=13 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=14 en-affil= Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=15 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=126 cd-vols= no-issue=38 article-no= start-page=7212 end-page=7228 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220915 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Roles of the Flexible Primary Coordination Sphere of the Mn4CaOx Cluster: What Are the Immediate Decay Products of the S-3 State? en-subtitle= kn-subtitle= en-abstract= kn-abstract=The primary coordination sphere of the multinuclear cofactor (Mn4CaOx) in the oxygen-evolving complex (OEC) of photosystem II is absolutely conserved to maintain its structure and function. Recent time-resolved serial femtosecond crystallography identified large reorganization of the primary coordination sphere in the S-2 to S-3 transition, which elicits a cascade of events involving Mn oxidation and water molecule binding to a putative catalytic Mn site. We examined how the crystallographic fields, created by transient conformational states of the OEC at various time points, affect the thermodynamics of various isomers of the Mn cluster using DFT calculations, with an aim of comprehending the functional roles of the flexible primary coordination sphere in the S-2 to S-3 transition and in the recovery of the S-2 state. The results show that the relative movements of surrounding residues change the size and shape of the cavity of the cluster and thereby affect the thermodynamics of various catalytic intermediates as well as the ability to capture a new water molecule at a coordinatively unsaturated site. The implication of these findings is that the protein dynamics may serve to gate the catalytic reaction efficiently by controlling the sequence of Mn oxidation/reduction and water binding/release. This interpretation is consistent with EPR experiments; g similar to 5 and g similar to 3 signals obtained after near-infrared (NIR) excitation of the S-3 state at 4 K and a g similar to 5 only signal produced after prolonged incubation of the S-3 state at 77 K can be best explained as originating from water-bound S-2 clusters (S-total = 7/2) under a S-3 ligand field, i.e., the immediate one-electron reduction products of the oxyl-oxo (S-total = 6) and hydroxo-oxo (S-total = 3) species in the S-3 state. en-copyright= kn-copyright= en-aut-name=IsobeHiroshi en-aut-sei=Isobe en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShojiMitsuo en-aut-sei=Shoji en-aut-mei=Mitsuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SuzukiTakayoshi en-aut-sei=Suzuki en-aut-mei=Takayoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YamaguchiKizashi en-aut-sei=Yamaguchi en-aut-mei=Kizashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Center for Computational Science, University of Tsukuba, kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=5 en-affil=Institute for NanoScience Design, Osaka University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue= article-no= start-page=e73990 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220411 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for the absence of low-energy chlorophylls in a photosystem I trimer from Gloeobacter violaceus en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem I (PSI) is a multi-subunit pigment-protein complex that functions in light-harvesting and photochemical charge-separation reactions, followed by reduction of NADP to NADPH required for CO2 fixation in photosynthetic organisms. PSI from different photosynthetic organisms has a variety of chlorophylls (Chls), some of which are at lower-energy levels than its reaction center P700, a special pair of Chls, and are called low-energy Chls. However, the sites of low-energy Chls are still under debate. Here, we solved a 2.04-& ANGS; resolution structure of a PSI trimer by cryo-electron microscopy from a primordial cyanobacterium Gloeobacter violaceus PCC 7421, which has no low-energy Chls. The structure shows the absence of some subunits commonly found in other cyanobacteria, confirming the primordial nature of this cyanobacterium. Comparison with the known structures of PSI from other cyanobacteria and eukaryotic organisms reveals that one dimeric and one trimeric Chls are lacking in the Gloeobacter PSI. The dimeric and trimeric Chls are named Low1 and Low2, respectively. Low2 is missing in some cyanobacterial and eukaryotic PSIs, whereas Low1 is absent only in Gloeobacter. These findings provide insights into not only the identity of low-energy Chls in PSI, but also the evolutionary changes of low-energy Chls in oxyphototrophs. en-copyright= kn-copyright= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HamaguchiTasuku en-aut-sei=Hamaguchi en-aut-mei=Tasuku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UenoYoshifumi en-aut-sei=Ueno en-aut-mei=Yoshifumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=UchidaHiroko en-aut-sei=Uchida en-aut-mei=Hiroko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MurakamiAkio en-aut-sei=Murakami en-aut-mei=Akio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=YokonoMakio en-aut-sei=Yokono en-aut-mei=Makio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=YonekuraKoji en-aut-sei=Yonekura en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=5 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=6 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=7 en-affil=Research Center for Inland Seas, Kobe University kn-affil= affil-num=8 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Institute of Low Temperature Science, Hokkaido University kn-affil= affil-num=11 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=12 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=13 en-affil=Biostructural Mechanism Laboratory, RIKEN SPring-8 Center kn-affil= affil-num=14 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=photosystem I kn-keyword=photosystem I en-keyword=cryo-EM kn-keyword=cryo-EM en-keyword=low-energy Chl kn-keyword=low-energy Chl en-keyword=Gloeobacter kn-keyword=Gloeobacter en-keyword=Other kn-keyword=Other END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=1 article-no= start-page=1764 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220401 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for different types of hetero-tetrameric light-harvesting complexes in a diatom PSII-FCPII supercomplex en-subtitle= kn-subtitle= en-abstract= kn-abstract=Fucoxanthin chlorophyll (Chl) a/c-binding proteins (FCPs) function as light harvesters in diatoms. The structure of a diatom photosystem II-FCPII (PSII-FCPII) supercomplex have been solved by cryo-electron microscopy (cryo-EM) previously; however, the FCPII subunits that constitute the FCPII tetramers and monomers are not identified individually due to their low resolutions. Here, we report a 2.5 angstrom resolution structure of the PSII-FCPII supercomplex using cryo-EM. Two types of tetrameric FCPs, S-tetramer, and M-tetramer, are identified as different types of hetero-tetrameric complexes. In addition, three FCP monomers, m1, m2, and m3, are assigned to different gene products of FCP. The present structure also identifies the positions of most Chls c and diadinoxanthins, which form a complicated pigment network. Excitation-energy transfer from FCPII to PSII is revealed by time-resolved fluorescence spectroscopy. These structural and spectroscopic findings provide insights into an assembly model of FCPII and its excitation-energy transfer and quenching processes. Fucoxanthin chlorophyll a/c-binding proteins (FCPs) harvest light energy in diatoms. The authors analyzed a structure of PSII-FCPII supercomplex at high resolution by cryo-EM, which identified each FCP subunit and pigment network in the supercomplex. en-copyright= kn-copyright= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KumazawaMinoru en-aut-sei=Kumazawa en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=IfukuKentaro en-aut-sei=Ifuku en-aut-mei=Kentaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YokonoMakio en-aut-sei=Yokono en-aut-mei=Makio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=MiyazakiNaoyuki en-aut-sei=Miyazaki en-aut-mei=Naoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Biostudies, Kyoto University kn-affil= affil-num=4 en-affil=Graduate School of Agriculture, Kyoto University kn-affil= affil-num=5 en-affil=Institute of Low Temperature Science, Hokkaido University kn-affil= affil-num=6 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=7 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=9 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=10 en-affil=Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba kn-affil= affil-num=11 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=6236 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20211029 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for high selectivity of a rice silicon channel Lsi1 en-subtitle= kn-subtitle= en-abstract= kn-abstract=Silicon (Si), the most abundant mineral element in the earthfs crust, is taken up by plant roots in the form of silicic acid through Low silicon rice 1 (Lsi1). Lsi1 belongs to the Nodulin 26-like intrinsic protein subfamily in aquaporin and shows high selectivity for silicic acid. To uncover the structural basis for this high selectivity, here we show the crystal structure of the rice Lsi1 at a resolution of 1.8 ?. The structure reveals transmembrane helical orientations different from other aquaporins, characterized by a unique, widely opened, and hydrophilic selectivity filter (SF) composed of five residues. Our structural, functional, and theoretical investigations provide a solid structural basis for the Si uptake mechanism in plants, which will contribute to secure and sustainable rice production by manipulating Lsi1 selectivity for different metalloids. en-copyright= kn-copyright= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Mitani-UenoNamiki en-aut-sei=Mitani-Ueno en-aut-mei=Namiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SaitoKeisuke en-aut-sei=Saito en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MatsukiKengo en-aut-sei=Matsuki en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YangLingli en-aut-sei=Yang en-aut-mei=Lingli kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=IshikitaHiroshi en-aut-sei=Ishikita en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Research Center for Advanced Science and Technology, The University of Tokyo kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=7 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=8 en-affil=Research Center for Advanced Science and Technology, The University of Tokyo kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=10 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=11 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue=1 article-no= start-page=382 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210322 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=High-resolution cryo-EM structure of photosystem II reveals damage from high-dose electron beams en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure and some intermediate structures. However, these structures are in the crystalline state and its final state structure has not been solved. Here we analyzed the structure of PSII in solution at 1.95?? resolution by single-particle cryo-electron microscopy (cryo-EM). The structure obtained is similar to the crystal structure, but a PsbY subunit was visible in the cryo-EM structure, indicating that it represents its physiological state more closely. Electron beam damage was observed at a high-dose in the regions that were easily affected by redox states, and reducing the beam dosage by reducing frames from 50 to 2 yielded a similar resolution but reduced the damage remarkably. This study will serve as a good indicator for determining damage-free cryo-EM structures of not only PSII but also all biological samples, especially redox-active metalloproteins. en-copyright= kn-copyright= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyazakiNaoyuki en-aut-sei=Miyazaki en-aut-mei=Naoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HamaguchiTasuku en-aut-sei=Hamaguchi en-aut-mei=Tasuku kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YonekuraKoji en-aut-sei=Yonekura en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba kn-affil= affil-num=3 en-affil=Biostructural Mechanism Laboratory, RIKEN Spring-8 Center kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Institute of Multidisciplinary Research for Advanced Materials, Tohoku University kn-affil= affil-num=7 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=1100 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210217 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of photosystem I-LHCI-LHCII from the green alga Chlamydomonas reinhardtii in State 2 en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem I (PSI) and II (PSII) balance their light energy distribution absorbed by their light-harvesting complexes (LHCs) through state transition to maintain the maximum photosynthetic performance and to avoid photodamage. In state 2, a part of LHCII moves to PSI, forming a PSI-LHCI-LHCII supercomplex. The green alga Chlamydomonas reinhardtii exhibits state transition to a far larger extent than higher plants. Here we report the cryo-electron microscopy structure of a PSI-LHCI-LHCII supercomplex in state 2 from C. reinhardtii at 3.42?? resolution. The result reveals that the PSI-LHCI-LHCII of C. reinhardtii binds two LHCII trimers in addition to ten LHCI subunits. The PSI core subunits PsaO and PsaH, which were missed or not well-resolved in previous Cr-PSI-LHCI structures, are observed. The present results reveal the organization and assembly of PSI core subunits, LHCI and LHCII, pigment arrangement, and possible pathways of energy transfer from peripheral antennae to the PSI core. en-copyright= kn-copyright= en-aut-name=HuangZihui en-aut-sei=Huang en-aut-mei=Zihui kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShenLiangliang en-aut-sei=Shen en-aut-mei=Liangliang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WangWenda en-aut-sei=Wang en-aut-mei=Wenda kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MaoZhiyuan en-aut-sei=Mao en-aut-mei=Zhiyuan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YiXiaohan en-aut-sei=Yi en-aut-mei=Xiaohan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KuangTingyun en-aut-sei=Kuang en-aut-mei=Tingyun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ZhangXing en-aut-sei=Zhang en-aut-mei=Xing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=HanGuangye en-aut-sei=Han en-aut-mei=Guangye kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine kn-affil= affil-num=2 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=3 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=5 en-affil=Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine kn-affil= affil-num=6 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=7 en-affil=Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine kn-affil= affil-num=9 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=1 article-no= start-page=10 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210216 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Antenna arrangement and energy-transfer pathways of PSI-LHCI from the moss Physcomitrella patens en-subtitle= kn-subtitle= en-abstract= kn-abstract=Plants harvest light energy utilized for photosynthesis by light-harvesting complex I and II (LHCI and LHCII) surrounding photosystem I and II (PSI and PSII), respectively. During the evolution of green plants, moss is at an evolutionarily intermediate position from aquatic photosynthetic organisms to land plants, being the first photosynthetic organisms that landed. Here, we report the structure of the PSI-LHCI supercomplex from the moss Physcomitrella patens (Pp) at 3.23 angstrom resolution solved by cryo-electron microscopy. Our structure revealed that four Lhca subunits are associated with the PSI core in an order of Lhca1-Lhca5-Lhca2-Lhca3. This number is much decreased from 8 to 10, the number of subunits in most green algal PSI-LHCI, but the same as those of land plants. Although Pp PSI-LHCI has a similar structure as PSI-LHCI of land plants, it has Lhca5, instead of Lhca4, in the second position of Lhca, and several differences were found in the arrangement of chlorophylls among green algal, moss, and land plant PSI-LHCI. One chlorophyll, PsaF-Chl 305, which is found in the moss PSI-LHCI, is located at the gap region between the two middle Lhca subunits and the PSI core, and therefore may make the excitation energy transfer from LHCI to the core more efficient than that of land plants. On the other hand, energy-transfer paths at the two side Lhca subunits are relatively conserved. These results provide a structural basis for unravelling the mechanisms of light-energy harvesting and transfer in the moss PSI-LHCI, as well as important clues on the changes of PSI-LHCI after landing. en-copyright= kn-copyright= en-aut-name=YanQiujing en-aut-sei=Yan en-aut-mei=Qiujing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ZhaoLiang en-aut-sei=Zhao en-aut-mei=Liang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WangWenda en-aut-sei=Wang en-aut-mei=Wenda kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=PiXiong en-aut-sei=Pi en-aut-mei=Xiong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HanGuangye en-aut-sei=Han en-aut-mei=Guangye kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=WangJie en-aut-sei=Wang en-aut-mei=Jie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ChengLingpeng en-aut-sei=Cheng en-aut-mei=Lingpeng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=HeYi-Kun en-aut-sei=He en-aut-mei=Yi-Kun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=KuangTingyun en-aut-sei=Kuang en-aut-mei=Tingyun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=QinXiaochun en-aut-sei=Qin en-aut-mei=Xiaochun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=SuiSen-Fang en-aut-sei=Sui en-aut-mei=Sen-Fang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= affil-num=1 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=2 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=3 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=5 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=6 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=7 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=8 en-affil=College of Life Sciences, Department of Chemistry, Capital Normal University, kn-affil= affil-num=9 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=10 en-affil=School of Biological Science and Technology, University of Jinan kn-affil= affil-num=11 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=12 en-affil=Research Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, kn-affil= END start-ver=1.4 cd-journal=joma no-vol=405 cd-vols= no-issue= article-no= start-page=112905 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210115 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Exploring reaction pathways for the structural rearrangements of the Mn cluster induced by water binding in the S3 state of the oxygen evolving complex of photosystem II en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosynthetic oxidation of water to dioxygen is catalyzed by the Mn4CaO5 cluster in the protein-cofactor complex photosystem II. The light-driven catalytic cycle consists of four observable intermediates (S0, S1, S2, and S3) and one transient S4 state. Recently, using X-ray free-electron laser crystallography, two experimental groups independently observed incorporation of one additional oxygen into the cluster during the S2 to S3 transition, which is likely to represent a substrate. The present study implicates two competing reaction routes encountered during the structural rearrangement of the catalyst induced by the water binding and immediately preceding the formation of final stable forms in the S3 state. This mutually exclusive competition involves concerted versus stepwise conformational changes between two isomers, called open and closed cubane structures, which have different consequences on the immediate product in the S3 state. The concerted pathway involves a one-step conversion between two isomeric hydroxo forms without changes to the metal oxidation and total spin (Stotal?=?3) states. Alternatively, in the stepwise process, the bound waters are oxidized and transformed into an oxyl?oxo form in a higher spin (Stotal?=?6) state. Here, density functional calculations are used to characterize all relevant intermediates and transition structures and demonstrate that the stepwise pathway to the substrate activation is substantially favored over the concerted one, as evidenced by comparison of the activation barriers (11.1 and 20.9?kcal?mol?1, respectively). Only after formation of the oxyl?oxo precursor can the hydroxo species be generated; this occurs with a slow kinetics and an activation barrier of 17.8?kcal?mol?1. The overall thermodynamic driving force is likely to be controlled by the movements of two glutamate ligands, D1-Glu189 and CP43-Glu354, in the active site and ranges from very weak (+0.4?kcal mol?1) to very strong (?23.5?kcal?mol?1). en-copyright= kn-copyright= en-aut-name=IsobeHiroshi en-aut-sei=Isobe en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShojiMitsuo en-aut-sei=Shoji en-aut-mei=Mitsuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SuzukiTakayoshi en-aut-sei=Suzuki en-aut-mei=Takayoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YamaguchiKizashi en-aut-sei=Yamaguchi en-aut-mei=Kizashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Center for Computational Science, University of Tsukuba kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=5 en-affil=Institute for NanoScience Design, Osaka University kn-affil= en-keyword=Photosynthesis kn-keyword=Photosynthesis en-keyword=Water oxidation kn-keyword=Water oxidation en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=Oxygen evolving complex kn-keyword=Oxygen evolving complex en-keyword=Mn4CaO6 cluster kn-keyword=Mn4CaO6 cluster en-keyword=Ligand environment kn-keyword=Ligand environment END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=5081 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20201008 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for energy transfer in a huge diatom PSI-FCPI supercomplex en-subtitle= kn-subtitle= en-abstract= kn-abstract=Diatom is an important group of marine algae and contributes to around 20% of the global photosynthetic carbon fixation. Photosystem I (PSI) of diatoms is associated with a large number of fucoxanthin-chlorophyll a/c proteins (FCPIs). We report the structure of PSI-FCPI from a diatom Chaetoceros gracilis at 2.38?? resolution by single-particle cryo-electron microscopy. PSI-FCPI is a monomeric supercomplex consisting of 12 core and 24 antenna subunits (FCPIs), and 326 chlorophylls a, 34 chlorophylls c, 102 fucoxanthins, 35 diadinoxanthins, 18 ƒΐ-carotenes and some electron transfer cofactors. Two subunits designated PsaR and PsaS were found in the core, whereas several subunits were lost. The large number of pigments constitute a unique and huge network ensuring efficient energy harvesting, transfer and dissipation. These results provide a firm structural basis for unraveling the mechanisms of light-energy harvesting, transfer and quenching in the diatom PSI-FCPI, and also important clues to evolutionary changes of PSI-LHCI. en-copyright= kn-copyright= en-aut-name=XuCaizhe en-aut-sei=Xu en-aut-mei=Caizhe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=PiXiong en-aut-sei=Pi en-aut-mei=Xiong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HuangYawen en-aut-sei=Huang en-aut-mei=Yawen kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HanGuangye en-aut-sei=Han en-aut-mei=Guangye kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ChenXiaobo en-aut-sei=Chen en-aut-mei=Xiaobo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=QinXiaochun en-aut-sei=Qin en-aut-mei=Xiaochun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=HuangGuoqiang en-aut-sei=Huang en-aut-mei=Guoqiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ZhaoSonghao en-aut-sei=Zhao en-aut-mei=Songhao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=YangYanyan en-aut-sei=Yang en-aut-mei=Yanyan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KuangTingyun en-aut-sei=Kuang en-aut-mei=Tingyun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=WangWenda en-aut-sei=Wang en-aut-mei=Wenda kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=SuiSen-Fang en-aut-sei=Sui en-aut-mei=Sen-Fang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= affil-num=1 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=2 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=3 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=4 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=5 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=6 en-affil=School of Biological Science and Technology, University of Jinan kn-affil= affil-num=7 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=8 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=9 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=10 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=11 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, The Chinese Academy of Sciences kn-affil= affil-num=12 en-affil=State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University kn-affil= affil-num=13 en-affil=Research Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Bioenergetics kn-keyword=Bioenergetics en-keyword=Cryoelectron microscopy kn-keyword=Cryoelectron microscopy en-keyword=Photosystem I kn-keyword=Photosystem I END start-ver=1.4 cd-journal=joma no-vol=1861 cd-vols= no-issue=7 article-no= start-page=148191 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200701 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Spectral tuning of light-harvesting complex II in the siphonous alga Bryopsis corticulans and its effect on energy transfer dynamics en-subtitle= kn-subtitle= en-abstract= kn-abstract=Light-harvesting complex II (LHCII) from the marine green macroalga Bryopsis corticulans is spectroscopically characterized to understand the structural and functional changes resulting from adaptation to intertidal environment. LHCII is homologous to its counterpart in land plants but has a different carotenoid and chlorophyll (Chl) composition. This is reflected in the steady-state absorption, fluorescence, linear dichroism, circular dichroism and anisotropic circular dichroism spectra. Time-resolved fluorescence and two-dimensional electronic spectroscopy were used to investigate the consequences of this adaptive change in the pigment composition on the excited-state dynamics. The complex contains additional Chl b spectral forms ? absorbing at around 650 nm and 658 nm ? and lacks the red-most Chl a forms compared with higher-plant LHCII. Similar to plant LHCII, energy transfer between Chls occurs on timescales from under hundred fs (mainly from Chl b to Chl a) to several picoseconds (mainly between Chl a pools). However, the presence of long-lived, weakly coupled Chl b and Chl a states leads to slower exciton equilibration in LHCII from B. corticulans. The finding demonstrates a trade-off between the enhanced absorption of blue-green light and the excitation migration time. However, the adaptive change does not result in a significant drop in the overall photochemical efficiency of Photosystem II. These results show that LHCII is a robust adaptable system whose spectral properties can be tuned to the environment for optimal light harvesting. en-copyright= kn-copyright= en-aut-name=AkhtarParveen en-aut-sei=Akhtar en-aut-mei=Parveen kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NowakowskiPawe? J. en-aut-sei=Nowakowski en-aut-mei=Pawe? J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WangWenda en-aut-sei=Wang en-aut-mei=Wenda kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=DoThanh Nhut en-aut-sei=Do en-aut-mei=Thanh Nhut kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ZhaoSonghao en-aut-sei=Zhao en-aut-mei=Songhao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SiligardiGiuliano en-aut-sei=Siligardi en-aut-mei=Giuliano kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=GarabGy?z? en-aut-sei=Garab en-aut-mei=Gy?z? kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TanHowe-Siang en-aut-sei=Tan en-aut-mei=Howe-Siang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=LambrevPetar H. en-aut-sei=Lambrev en-aut-mei=Petar H. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Biological Research Centre kn-affil= affil-num=2 en-affil=ivision of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University kn-affil= affil-num=3 en-affil=Photosynthesis Research Centre, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University kn-affil= affil-num=5 en-affil=Photosynthesis Research Centre, Chinese Academy of Sciences kn-affil= affil-num=6 en-affil=Diamond Light Source Ltd., Harwell Science and Innovation Campus kn-affil= affil-num=7 en-affil=Biological Research Centre kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=9 en-affil=Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University kn-affil= affil-num=10 en-affil=Biological Research Centre kn-affil= en-keyword=Circular dichroism kn-keyword=Circular dichroism en-keyword=Light-harvesting complexes kn-keyword=Light-harvesting complexes en-keyword=Marine algae kn-keyword=Marine algae en-keyword=Photosynthesis kn-keyword=Photosynthesis en-keyword=Time-resolved spectroscopy kn-keyword=Time-resolved spectroscopy en-keyword=Two-dimensional spectroscopy kn-keyword=Two-dimensional spectroscopy END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue=1 article-no= start-page=232 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200511 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of a cyanobacterial photosystem I surrounded by octadecameric IsiA antenna proteins en-subtitle= kn-subtitle= en-abstract= kn-abstract=Iron-stress induced protein A (IsiA) is a chlorophyll-binding membrane-spanning protein in photosynthetic prokaryote cyanobacteria, and is associated with photosystem I (PSI) trimer cores, but its structural and functional significance in light harvesting remains unclear. Here we report a 2.7-angstrom resolution cryo-electron microscopic structure of a supercomplex between PSI core trimer and IsiA from a thermophilic cyanobacterium Thermosynechococcus vulcanus. The structure showed that 18 IsiA subunits form a closed ring surrounding a PSI trimer core. Detailed arrangement of pigments within the supercomplex, as well as molecular interactions between PSI and IsiA and among IsiAs, were resolved. Time-resolved fluorescence spectra of the PSI-IsiA supercomplex showed clear excitation-energy transfer from IsiA to PSI, strongly indicating that IsiA functions as an energy donor, but not an energy quencher, in the supercomplex. These structural and spectroscopic findings provide important insights into the excitation-energy-transfer and subunit assembly mechanisms in the PSI-IsiA supercomplex. Akita et al. present the latest approach to solve IsiA-PSI supercomplex molecular structure with increased resolution using cryo-EM and time-resolved fluorescence studies. With 2.7 angstrom resolution, they reveal molecular interactions between PSI and IsiA subunits and that IsiA functions as an energy donor in the supercomplex. en-copyright= kn-copyright= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YokonoMakio en-aut-sei=Yokono en-aut-mei=Makio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=UenoYoshifumi en-aut-sei=Ueno en-aut-mei=Yoshifumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MiyazakiNaoyuki en-aut-sei=Miyazaki en-aut-mei=Naoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Nippon Flour Mills Co., Ltd., Innovation Center kn-affil= affil-num=6 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=7 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=8 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=9 en-affil= Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=11 en-affil=Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba kn-affil= en-keyword=Cryoelectron microscopy kn-keyword=Cryoelectron microscopy en-keyword=Photosystem I kn-keyword=Photosystem I END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200518 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for assembly and function of a diatom photosystem I-light-harvesting supercomplex en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosynthetic light-harvesting complexes (LHCs) play a pivotal role in collecting solar energy for photochemical reactions in photosynthesis. One of the major LHCs are fucoxanthin chlorophyll a/c-binding proteins (FCPs) present in diatoms, a group of organisms having important contribution to the global carbon cycle. Here, we report a 2.40-angstrom resolution structure of the diatom photosystem I (PSI)-FCPI supercomplex by cryo-electron microscopy. The supercomplex is composed of 16 different FCPI subunits surrounding a monomeric PSI core. Each FCPI subunit showed different protein structures with different pigment contents and binding sites, and they form a complicated pigment-protein network together with the PSI core to harvest and transfer the light energy efficiently. In addition, two unique, previously unidentified subunits were found in the PSI core. The structure provides numerous insights into not only the light-harvesting strategy in diatom PSI-FCPI but also evolutionary dynamics of light harvesters among oxyphototrophs. One of the major photosynthetic light-harvesting complexes (LHCs) are fucoxanthin chlorophyll a/c-binding proteins (FCPs), which are present in diatoms, a major group of algae. Here, the authors present the cryo-EM structure of the photosystem I-FCP (PSI-FCPI) supercomplex isolated from the marine centric diatom Chaetoceros gracilis that contains 16 FCPI subunits surrounding the PSI core and discuss possible excitation energy transfer pathways. en-copyright= kn-copyright= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IfukuKentaro en-aut-sei=Ifuku en-aut-mei=Kentaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KumazawaMinoru en-aut-sei=Kumazawa en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=UchiyamaIkuo en-aut-sei=Uchiyama en-aut-mei=Ikuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KashinoYasuhiro en-aut-sei=Kashino en-aut-mei=Yasuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MiyazakiNaoyuki en-aut-sei=Miyazaki en-aut-mei=Naoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Biostudies, Kyoto University kn-affil= affil-num=4 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=5 en-affil=Faculty of Agriculture, Kyoto University kn-affil= affil-num=6 en-affil=National Institute for Basic Biology, National Institutes of Natural Sciences kn-affil= affil-num=7 en-affil=Graduate School of Life Science, University of Hyogo kn-affil= affil-num=8 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=9 en-affil=Graduate School of Science,Kobe University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=11 en-affil=Institute for Protein Research, Osaka University kn-affil= affil-num=12 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=238 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200113 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for the adaptation and function of chlorophyll f in photosystem I en-subtitle= kn-subtitle= en-abstract= kn-abstract=Chlorophylls (Chl) play pivotal roles in energy capture, transfer and charge separation in photosynthesis. Among Chls functioning in oxygenic photosynthesis, Chl f is the most red-shifted type first found in a cyanobacterium Halomicronema hongdechloris. The location and function of Chl f in photosystems are not clear. Here we analyzed the high-resolution structures of photosystem I (PSI) core from H. hongdechloris grown under white or far-red light by cryo-electron microscopy. The structure showed that, far-red PSI binds 83 Chl a and 7 Chl f, and Chl f are associated at the periphery of PSI but not in the electron transfer chain. The appearance of Chl f is well correlated with the expression of PSI genes induced under far-red light. These results indicate that Chl f functions to harvest the far-red light and enhance uphill energy transfer, and changes in the gene sequences are essential for the binding of Chl f. en-copyright= kn-copyright= en-aut-name=KatoKoji en-aut-sei=Kato en-aut-mei=Koji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShinodaToshiyuki en-aut-sei=Shinoda en-aut-mei=Toshiyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AkimotoSeiji en-aut-sei=Akimoto en-aut-mei=Seiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=DohmaeNaoshi en-aut-sei=Dohmae en-aut-mei=Naoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ChenMin en-aut-sei=Chen en-aut-mei=Min kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=AllakhverdievSuleyman I. en-aut-sei=Allakhverdiev en-aut-mei=Suleyman I. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MiyazakiNaoyuki en-aut-sei=Miyazaki en-aut-mei=Naoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=TomoTatsuya en-aut-sei=Tomo en-aut-mei=Tatsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Faculty of Science, Tokyo University of Science kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Science, Kobe University kn-affil= affil-num=5 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=6 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science kn-affil= affil-num=7 en-affil=School of Life and Environmental Sciences, University of Sydney kn-affil= affil-num=8 en-affil=K.A. Timiryazev Institute of Plant Physiology RAS kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=11 en-affil=Institute for Protein Research, Laboratory of Protein Synthesis and Expression, Osaka University kn-affil= affil-num=12 en-affil=Faculty of Science, Tokyo University of Science kn-affil= END start-ver=1.4 cd-journal=joma no-vol=1864 cd-vols= no-issue=2 article-no= start-page=129466 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200229 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Time-resolved studies of metalloproteins using X-ray free electron laser radiation at SACLA en-subtitle= kn-subtitle= en-abstract= kn-abstract=Background: The invention of the X-ray free-electron laser (XFEL) has provided unprecedented new opportunities for structural biology. The advantage of XFEL is an intense pulse of X-rays and a very short pulse duration (<10 fs) promising a damage-free and time-resolved crystallography approach.
Scope of review: Recent time-resolved crystallographic analyses in XFEL facility SACLA are reviewed. Specifically, metalloproteins involved in the essential reactions of bioenergy conversion including photosystem II, cytochrome c oxidase and nitric oxide reductase are described.
Major conclusions: XFEL with pump-probe techniques successfully visualized the process of the reaction and the dynamics of a protein. Since the active center of metalloproteins is very sensitive to the X-ray radiation, damage-free structures obtained by XFEL are essential to draw mechanistic conclusions. Methods and tools for sample delivery and reaction initiation are key for successful measurement of the time-resolved data.
General significance: XFEL is at the center of approaches to gain insight into complex mechanism of structural dynamics and the reactions catalyzed by biological macromolecules. Further development has been carried out to expand the application of time-resolved X-ray crystallography. This article is part of a Special Issue entitled Novel measurement techniques for visualizing 'live' protein molecules. en-copyright= kn-copyright= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ShimadaAtsuhiro en-aut-sei=Shimada en-aut-mei=Atsuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ToshaTakehiko en-aut-sei=Tosha en-aut-mei=Takehiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SugimotoHiroshi en-aut-sei=Sugimoto en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Applied Biological Sciences and Faculty of Applied Biological Sciences, Gifu University kn-affil= affil-num=3 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center kn-affil= affil-num=6 en-affil=Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center kn-affil= en-keyword=Heme kn-keyword=Heme en-keyword=Metalloproteins kn-keyword=Metalloproteins en-keyword=Proton pump kn-keyword=Proton pump en-keyword=Radiation damage kn-keyword=Radiation damage en-keyword=Serial femtosecond crystallography kn-keyword=Serial femtosecond crystallography en-keyword=X-ray free-electron laser kn-keyword=X-ray free-electron laser END start-ver=1.4 cd-journal=joma no-vol=366 cd-vols= no-issue=6463 article-no= start-page=334 end-page=338 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191018 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An oxyl/oxo mechanism for dioxygen bond formation in PSII revealed by X-ray free electron lasers en-subtitle= kn-subtitle= en-abstract= kn-abstract= Photosynthetic water oxidation is catalyzed by the Mn4CaO5 cluster of photosystem II (PSII) with linear progression through five S-state intermediates (S0 to S4). To reveal the mechanism of water oxidation, we analyzed structures of PSII in the S1, S2, and S3 states by x-ray free-electron laser serial crystallography. No insertion of water was found in S2, but flipping of D1 Glu189 upon transition to S3 leads to the opening of a water channel and provides a space for incorporation of an additional oxygen ligand, resulting in an open cubane Mn4CaO6 cluster with an oxyl/oxo bridge. Structural changes of PSII between the different S states reveal cooperative action of substrate water access, proton release, and dioxygen formation in photosynthetic water oxidation. en-copyright= kn-copyright= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamashitaKeitaro en-aut-sei=Yamashita en-aut-mei=Keitaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UenoGo en-aut-sei=Ueno en-aut-mei=Go kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=LiHongjie en-aut-sei=Li en-aut-mei=Hongjie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamaneTakahiro en-aut-sei=Yamane en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=HirataKunio en-aut-sei=Hirata en-aut-mei=Kunio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=YonekuraShinichiro en-aut-sei=Yonekura en-aut-mei=Shinichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=YuLong-Jiang en-aut-sei=Yu en-aut-mei=Long-Jiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=MurakamiHironori en-aut-sei=Murakami en-aut-mei=Hironori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=NomuraTakashi en-aut-sei=Nomura en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=KimuraTetsunari en-aut-sei=Kimura en-aut-mei=Tetsunari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=KuboMinoru en-aut-sei=Kubo en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=BabaSeiki en-aut-sei=Baba en-aut-mei=Seiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=KumasakaTakashi en-aut-sei=Kumasaka en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=TonoKensuke en-aut-sei=Tono en-aut-mei=Kensuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=YabashiMakina en-aut-sei=Yabashi en-aut-mei=Makina kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=IsobeHiroshi en-aut-sei=Isobe en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= en-aut-name=YamaguchiKizashi en-aut-sei=Yamaguchi en-aut-mei=Kizashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=21 ORCID= en-aut-name=YamamotoMasaki en-aut-sei=Yamamoto en-aut-mei=Masaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=22 ORCID= en-aut-name=AgoHideo en-aut-sei=Ago en-aut-mei=Hideo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=23 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=24 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=11 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=12 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=13 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=14 en-affil=Department of Chemistry, Graduate School of Science, Kobe University kn-affil= affil-num=15 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=16 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=17 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=18 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=19 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=20 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=21 en-affil=The Institute for Scientific and Industrial Research, Osaka University kn-affil= affil-num=22 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=23 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=24 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=543 cd-vols= no-issue=7643 article-no= start-page=131 end-page=135 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=201703 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Light-induced structural changes and the site of O=O bond formation in PSII caught by XFEL en-subtitle= kn-subtitle= en-abstract= kn-abstract= Photosystem II (PSII) is a huge membrane-protein complex consisting of 20 different subunits with a total molecular mass of 350?kDa for a monomer. It catalyses light-driven water oxidation at its catalytic centre, the oxygen-evolving complex (OEC). The structure of PSII has been analysed at 1.9?? resolution by synchrotron radiation X-rays, which revealed that the OEC is a Mn4CaO5 cluster organized in an asymmetric, 'distorted-chair' form. This structure was further analysed with femtosecond X-ray free electron lasers (XFEL), providing the 'radiation damage-free' structure. The mechanism of O=O bond formation, however, remains obscure owing to the lack of intermediate-state structures. Here we describe the structural changes in PSII induced by two-flash illumination at room temperature at a resolution of 2.35?? using time-resolved serial femtosecond crystallography with an XFEL provided by the SPring-8 ?ngstr?m compact free-electron laser. An isomorphous difference Fourier map between the two-flash and dark-adapted states revealed two areas of apparent changes: around the QB/non-haem iron and the Mn4CaO5 cluster. The changes around the QB/non-haem iron region reflected the electron and proton transfers induced by the two-flash illumination. In the region around the OEC, a water molecule located 3.5?? from the Mn4CaO5 cluster disappeared from the map upon two-flash illumination. This reduced the distance between another water molecule and the oxygen atom O4, suggesting that proton transfer also occurred. Importantly, the two-flash-minus-dark isomorphous difference Fourier map showed an apparent positive peak around O5, a unique ƒΚ4-oxo-bridge located in the quasi-centre of Mn1 and Mn4 (refs 4,5). This suggests the insertion of a new oxygen atom (O6) close to O5, providing an O=O distance of 1.5?? between these two oxygen atoms. This provides a mechanism for the O=O bond formation consistent with that proposed previously en-copyright= kn-copyright= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SugaharaMichihiro en-aut-sei=Sugahara en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KuboMinoru en-aut-sei=Kubo en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NakaneTakanori en-aut-sei=Nakane en-aut-mei=Takanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamashitaKeitaro en-aut-sei=Yamashita en-aut-mei=Keitaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=NakabayashiMakoto en-aut-sei=Nakabayashi en-aut-mei=Makoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=YamaneTakahiro en-aut-sei=Yamane en-aut-mei=Takahiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=NakanoTakamitsu en-aut-sei=Nakano en-aut-mei=Takamitsu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=SuzukiMamoru en-aut-sei=Suzuki en-aut-mei=Mamoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=MasudaTetsuya en-aut-sei=Masuda en-aut-mei=Tetsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=InoueShigeyuki en-aut-sei=Inoue en-aut-mei=Shigeyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=KimuraTetsunari en-aut-sei=Kimura en-aut-mei=Tetsunari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=NomuraTakashi en-aut-sei=Nomura en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=YonekuraShinichiro en-aut-sei=Yonekura en-aut-mei=Shinichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=YuLong-Jiang en-aut-sei=Yu en-aut-mei=Long-Jiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=SakamotoTomohiro en-aut-sei=Sakamoto en-aut-mei=Tomohiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=MotomuraTaiki en-aut-sei=Motomura en-aut-mei=Taiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= en-aut-name=ChenJing-Hua en-aut-sei=Chen en-aut-mei=Jing-Hua kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=21 ORCID= en-aut-name=KatoYuki en-aut-sei=Kato en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=22 ORCID= en-aut-name=NoguchiTakumi en-aut-sei=Noguchi en-aut-mei=Takumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=23 ORCID= en-aut-name=TonoKensuke en-aut-sei=Tono en-aut-mei=Kensuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=24 ORCID= en-aut-name=JotiYasumasa en-aut-sei=Joti en-aut-mei=Yasumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=25 ORCID= en-aut-name=KameshimaTakashi en-aut-sei=Kameshima en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=26 ORCID= en-aut-name=HatsuiTakaki en-aut-sei=Hatsui en-aut-mei=Takaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=27 ORCID= en-aut-name=NangoEriko en-aut-sei=Nango en-aut-mei=Eriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=28 ORCID= en-aut-name=TanakaRie en-aut-sei=Tanaka en-aut-mei=Rie kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=29 ORCID= en-aut-name=NaitowHisashi en-aut-sei=Naitow en-aut-mei=Hisashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=30 ORCID= en-aut-name=MatsuuraYoshinori en-aut-sei=Matsuura en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=31 ORCID= en-aut-name=YamashitaAyumi en-aut-sei=Yamashita en-aut-mei=Ayumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=32 ORCID= en-aut-name=YamamotoMasaki en-aut-sei=Yamamoto en-aut-mei=Masaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=33 ORCID= en-aut-name=NurekiOsamu en-aut-sei=Nureki en-aut-mei=Osamu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=34 ORCID= en-aut-name=YabashiMakina en-aut-sei=Yabashi en-aut-mei=Makina kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=35 ORCID= en-aut-name=IshikawaTetsuya en-aut-sei=Ishikawa en-aut-mei=Tetsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=36 ORCID= en-aut-name=IwataSo en-aut-sei=Iwata en-aut-mei=So kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=37 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=38 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=4 en-affil=Japan Science and Technology Agency, PRESTO kn-affil= affil-num=5 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Biological Sciences, Graduate School of Science, The University of Tokyo kn-affil= affil-num=7 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=10 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=11 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=12 en-affil=Institute for Protein Research, Osaka University kn-affil= affil-num=13 en-affil=Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University kn-affil= affil-num=14 en-affil=Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo kn-affil= affil-num=15 en-affil=Department of Chemistry, Graduate School of Science, Kobe University kn-affil= affil-num=16 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=17 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=18 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=19 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=20 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=21 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=22 en-affil=Division of Material Science, Graduate School of Science, Nagoya University kn-affil= affil-num=23 en-affil=Division of Material Science, Graduate School of Science, Nagoya University kn-affil= affil-num=24 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=25 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=26 en-affil=Japan Synchrotron Radiation Research Institute46 kn-affil= affil-num=27 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=28 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=29 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=30 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=31 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=32 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=33 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=34 en-affil=Department of Biological Sciences, Graduate School of Science, The University of Tokyo kn-affil= affil-num=35 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=36 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=37 en-affil=RIKEN SPring-8 Center kn-affil= affil-num=38 en-affil=Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=39 cd-vols= no-issue= article-no= start-page=46 end-page=53 dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=201608 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure and energy transfer pathways of the plant photosystem I-LHCI supercomplex en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem I (PSI) is one of the two photosystems in oxygenic photosynthesis, and absorbs light energy to generate reducing power for the reduction of NADP+ to NADPH with a quantum efficiency close to 100%. The plant PSI core forms a supercomplex with light-harvesting complex I (LHCI) with a total molecular weight of over 600 kDa. Recent X-ray structure analysis of the PSI-LHCI membrane-protein supercomplex has revealed detailed arrangement of the light-harvesting pigments and other cofactors especially within LHCI. Here we introduce the overall structure of the PSI-LHCI supercomplex, and then focus on the excited energy transfer (EET) pathways from LHCI to the PSI core and photoprotection mechanisms based on the structure obtained. en-copyright= kn-copyright= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name=›—ΟŠ° kn-aut-sei=› kn-aut-mei=—ΟŠ° aut-affil-num=1 ORCID= en-aut-name=QinXiaochun en-aut-sei=Qin en-aut-mei=Xiaochun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KuangTingyun en-aut-sei=Kuang en-aut-mei=Tingyun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name=’ΎŒšm kn-aut-sei=’Ύ kn-aut-mei=Œšm aut-affil-num=4 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil=‰ͺŽR‘εŠwˆΩ•ͺ–μŠξ‘b‰ΘŠwŒ€‹†Š affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil=‰ͺŽR‘εŠwˆΩ•ͺ–μŠξ‘b‰ΘŠwŒ€‹†Š affil-num=3 en-affil=Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University kn-affil=‰ͺŽR‘εŠwˆΩ•ͺ–μŠξ‘b‰ΘŠwŒ€‹†Š END start-ver=1.4 cd-journal=joma no-vol=517 cd-vols= no-issue= article-no= start-page=99 end-page=103 dt-received= dt-revised= dt-accepted= dt-pub-year=2015 dt-pub=20150101 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Native structure of photosystem II at 1.95 ? resolution viewed by femtosecond X-ray pulses en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosynthesis converts light energy into biologically useful chemical energy vital to life on Earth. The initial reaction of photosynthesis takes place in photosystem II (PSII), a 700-kilodalton homodimeric membrane protein complex which catalyses photo-oxidation of water into dioxygen through an S-state cycle of the oxygen evolving complex (OEC). The structure of PSII has been solved by X-ray diffraction (XRD) at 1.9-?ngstr?m (?) resolution, which revealed that the OEC is a Mn4CaO5-cluster coordinated by a well-defined protein environment1. However, extended X-ray absorption fine structure (EXAFS) studies showed that the manganese cations in the OEC are easily reduced by X-ray irradiation2, and slight differences were found in the Mn?Mn distances between the results of XRD1, EXAFS3?7 and theoretical studies8?14. Here we report a eradiation-damage-freef structure of PSII from Thermosynechococcus vulcanus in the S1 state at a resolution of 1.95 ? using femtosecond X-ray pulses of the SPring-8 ?ngstr?m compact free-electron laser (SACLA) and a huge number of large, highly isomorphous PSII crystals. Compared with the structure from XRD, the OEC in the X-ray free electron laser structure has Mn?Mn distances that are shorter by 0.1?0.2 ?. The valences of each manganese atom were tentatively assigned as Mn1D(III), Mn2C(IV), Mn3B(IV) and Mn4A(III), based on the average Mn?ligand distances and analysis of the Jahn?Teller axis on Mn(III). One of the oxo-bridged oxygens, O5, has significantly longer Mn?O distances in contrast to the other oxo-oxygen atoms, suggesting that it is a hydroxide ion instead of a normal oxygen dianion and therefore may serve as one of the substrate oxygen atoms. These findings provide a structural basis for the mechanism of oxygen evolution, and we expect that this structure will provide a blueprint for design of artificial catalysts for water oxidation. en-copyright= kn-copyright= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AkitaFusamichi en-aut-sei=Akita en-aut-mei=Fusamichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HirataKunio en-aut-sei=Hirata en-aut-mei=Kunio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UenoGo en-aut-sei=Ueno en-aut-mei=Go kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MurakamiHironori en-aut-sei=Murakami en-aut-mei=Hironori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShimizuTetsuya en-aut-sei=Shimizu en-aut-mei=Tetsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=YamashitaKeitaro en-aut-sei=Yamashita en-aut-mei=Keitaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=YamamotoMasaki en-aut-sei=Yamamoto en-aut-mei=Masaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=AgoHideo en-aut-sei=Ago en-aut-mei=Hideo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil= kn-affil=Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=4 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=5 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=6 en-affil= kn-affil=Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University affil-num=7 en-affil= kn-affil=Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University affil-num=8 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=9 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=10 en-affil= kn-affil=RIKEN SPring-8 Center affil-num=11 en-affil= kn-affil=Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=1797 cd-vols= no-issue=2 article-no= start-page=278 end-page=284 dt-received= dt-revised= dt-accepted= dt-pub-year=2010 dt-pub=201002 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural and functional studies on Ycf12 (Psb30) and PsbZ-deletion mutants from a thermophilic cyanobacterium en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ycf12 (Psb30) and PsbZ are two low molecular weight subunits of photosystem II (PSII), with one and two trans-membrane helices, respectively. In order to study the functions of these two subunits from a structural point of view, we constructed deletion mutants lacking either Ycf12 or PsbZ from Thermosynechococcus elongatus, and purified, crystallized and analyzed the structure of PSII dimer from the two mutants. Our results showed that Ycf12 is located in the periphery of PSII, close to PsbK, PsbZ and PsbJ, and corresponded to the unassigned helix X1 reported previously, in agreement with the recent structure at 2.9 ? resolution (A. Guskov, J. Kern, A. Gabdulkhakov, M. Broser, A. Zouni, W. Saenger, Cyanobacterial photosystem II at 2.9 ? resolution: role of quinones, lipids, channels and chloride, Nat. Struct. Mol. Biol. 16 (2009) 334?342). On the other hand, crystals of PsbZ-deleted PSII showed a remarkably different unit cell constants from those of wild-type PSII, indicating a role of PsbZ in the interactions between PSII dimers within the crystal. This is the first example for a different arrangement of PSII dimers within the cyanobacterial PSII crystals. PSII dimers had a lower oxygen-evolving activity from both mutants than that from the wild type. In consistent with this, the relative content of PSII in the thylakoid membranes was lower in the two mutants than that in the wild type. These results suggested that deletion of both subunits affected the PSII activity, thereby destabilized PSII, leading to a decrease in the PSII content in vivo. While PsbZ was present in PSII purified from the Ycf12-deletion mutant, Ycf12 was present in crude PSII but absent in the finally purified PSII from the PsbZ-deletion mutant, indicating a preferential, stabilizing role of PsbZ for the binding of Ycf12 to PSII. These results were discussed in terms of the PSII crystal structure currently available en-copyright= kn-copyright= en-aut-name=TakasakaKenji en-aut-sei=Takasaka en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IwaiMasako en-aut-sei=Iwai en-aut-mei=Masako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=OhmoriYukari en-aut-sei=Ohmori en-aut-mei=Yukari kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=IkeuchiMasahiko en-aut-sei=Ikeuchi en-aut-mei=Masahiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=TakahashiYuichiro en-aut-sei=Takahashi en-aut-mei=Yuichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=KamiyaNobuo en-aut-sei=Kamiya en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=2 en-affil= kn-affil=Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science affil-num=3 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University affil-num=4 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=5 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=6 en-affil= kn-affil=Department of Life Sciences (Biology), Graduate School of Arts and Science, The University of Tokyo affil-num=7 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=8 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University affil-num=9 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=Mutant kn-keyword=Mutant en-keyword=Crystal structure kn-keyword=Crystal structure en-keyword=Ycf12 kn-keyword=Ycf12 en-keyword=PsbZ kn-keyword=PsbZ en-keyword=Oxygen evolution kn-keyword=Oxygen evolution END start-ver=1.4 cd-journal=joma no-vol=684 cd-vols= no-issue= article-no= start-page=41 end-page=51 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=2011 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Purification and Crystallization of Oxygen-Evolving Photosystem II Core Complex from Thermophilic Cyanobacteria en-subtitle= kn-subtitle= en-abstract= kn-abstract=This chapter describes the purification and crystallization of oxygen-evolving photosystem II core dimer complex from a thermophilic cyanobacterium Thermosynechococcus vulcanus. Procedures used for purification of photosystem II from the cyanobacterium involves cultivation of cells, isolation of thylakoid membranes, purification of crude and pure photosystem II core complexes by detergent solubilization, followed by differential centrifugation and column chromatography. The purified core dimer particles were successfully used for crystallization, and the methods and conditions used for crystallization are presented. These purification and crystallization procedures can be applied for another thermophilic cyanobacterium T. elongatus. en-copyright= kn-copyright= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KoikeHiroyuki en-aut-sei=Koike en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Department of Biosciences, Faculty of Science and Engineering, Chuo University en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=Oxygen evolution kn-keyword=Oxygen evolution en-keyword=Crystallization kn-keyword=Crystallization en-keyword=Membrane proteins kn-keyword=Membrane proteins en-keyword=Ion-exchange chromatography kn-keyword=Ion-exchange chromatography END start-ver=1.4 cd-journal=joma no-vol=285 cd-vols= no-issue=38 article-no= start-page=29191 end-page=29199 dt-received= dt-revised= dt-accepted= dt-pub-year=2010 dt-pub=20100917 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Binding and Functional Properties of Five Extrinsic Proteins in Oxygen-evolving Photosystem II from a Marine Centric Diatom, Chaetoceros gracilis en-subtitle= kn-subtitle= en-abstract= kn-abstract=Oxygen-evolving photosystem II (PSII) isolated from a marine centric diatom, Chaetoceros gracilis, contains a novel extrinsic protein (Psb31) in addition to four red algal type extrinsic proteins of PsbO, PsbQŒ, PsbV, and PsbU. In this study, the five extrinsic proteins were purified from alkaline Tris extracts of the diatom PSII by anion and cation exchange chromatographic columns at different pH values. Reconstitution experiments in various combinations with the purified extrinsic proteins showed that PsbO, PsbQŒ, and Psb31 rebound directly to PSII in the absence of other extrinsic proteins, indicating that these extrinsic proteins have their own binding sites in PSII intrinsic proteins. On the other hand, PsbV and PsbU scarcely rebound to PSII alone, and their effective bindings required the presence of all of the other extrinsic proteins. Interestingly, PSII reconstituted with Psb31 alone considerably restored the oxygen evolving activity in the absence of PsbO, indicating that Psb31 serves as a substitute in part for PsbO in supporting oxygen evolution. A significant difference found between PSIIs reconstituted with Psb31 and with PsbO is that the oxygen evolving activity of the former is scarcely stimulated by Cl? and Ca2+ ions but that of the latter is largely stimulated by these ions, although rebinding of PsbV and PsbU activated oxygen evolution in the absence of Cl? and Ca2+ ions in both the former and latter PSIIs. Based on these results, we proposed a model for the association of the five extrinsic proteins with intrinsic proteins in diatom PSII and compared it with those in PSIIs from the other organisms. en-copyright= kn-copyright= en-aut-name=NagaoRyo en-aut-sei=Nagao en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MoriguchiAkira en-aut-sei=Moriguchi en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TomoTatsuya en-aut-sei=Tomo en-aut-mei=Tatsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NiikuraAyako en-aut-sei=Niikura en-aut-mei=Ayako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NakajimaSaori en-aut-sei=Nakajima en-aut-mei=Saori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SuzukiTakehiro en-aut-sei=Suzuki en-aut-mei=Takehiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=OkumuraAkinori en-aut-sei=Okumura en-aut-mei=Akinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=IwaiMasako en-aut-sei=Iwai en-aut-mei=Masako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=IkeuchiMasahiko en-aut-sei=Ikeuchi en-aut-mei=Masahiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=EnamiIsao en-aut-sei=Enami en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil= kn-affil=Department of Life Sciences (Biology), Graduate School of Art and Sciences, University of Tokyo affil-num=2 en-affil= kn-affil=Department of Biology, Faculty of Science, Tokyo University of Science affil-num=3 en-affil= kn-affil=Department of Biology, Faculty of Science, Tokyo University of Science affil-num=4 en-affil= kn-affil=Division of Biosciences, Graduate School of Natural Science and Technology, Okayama University affil-num=5 en-affil= kn-affil=Department of Biology, Faculty of Science, Tokyo University of Science affil-num=6 en-affil= kn-affil=Biomolecular Characterization Team, Discovery Research Institute, RIKEN affil-num=7 en-affil= kn-affil=Department of Integrated Sciences in Physics and Biology, College of Humanities and Sciences, Nihon University affil-num=8 en-affil= kn-affil=Department of Life Sciences (Biology), Graduate School of Art and Sciences, University of Tokyo affil-num=9 en-affil= kn-affil=Division of Biosciences, Graduate School of Natural Science and Technology, Okayama University affil-num=10 en-affil= kn-affil=Department of Life Sciences (Biology), Graduate School of Art and Sciences, University of Tokyo affil-num=11 en-affil= kn-affil=Department of Biology, Faculty of Science, Tokyo University of Science END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue= article-no= start-page=373 end-page=389 dt-received= dt-revised= dt-accepted= dt-pub-year=2010 dt-pub=2010 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mechanisms of Acido-Tolerance and Characteristics of Photosystems in an Acidophilic and Thermophilic Red Alga, Cyanidium Caldarium en-subtitle= kn-subtitle= en-abstract= kn-abstract=In this chapter, we describe the mechanisms of acido-tolerance in an acidophilic- and thermophilic red alga, Cyanidium caldarium. In spite of the extremely acidic environments it inhabits, the intracellular pH of Cyanidium cells is kept neutral by pumping out the protons previously leaked into the cells according to the steep pH gradient. The H+ pump is driven by the plasma membrane ATPase, utilizing intracellular ATP produced by both oxidative phosphorylation and cyclic photophosphorylation via photosystem I. We also describe the characteristics and function of the two photosystems, Photosystem I (PSI) and II (PSII), in Cyanidium caldarium in comparison with those of cyanobacteria, other eukaryotic algae, and higher plants, based on the crystal structures of the two complexes reported so far. en-copyright= kn-copyright= en-aut-name=EnamiIsao en-aut-sei=Enami en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AdachiHideyuki en-aut-sei=Adachi en-aut-mei=Hideyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Biology, Faculty of Science, Tokyo University of Science affil-num=2 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=473 cd-vols= no-issue=7345 article-no= start-page=55 end-page=60 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=20110505 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Crystal structure of oxygen-evolving photosystem II at a resolution of 1.9?? en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem II is the site of photosynthetic water oxidation and contains 20 subunits with a total molecular mass of 350 kDa. The structure of photosystem II has been reported at resolutions from 3.8 to 2.9 angstrom. These resolutions have provided much information on the arrangement of protein subunits and cofactors but are insufficient to reveal the detailed structure of the catalytic centre of water splitting. Here we report the crystal structure of photosystem II at a resolution of 1.9 angstrom. From our electron density map, we located all of the metal atoms of the Mn(4)CaO(5) cluster, together with all of their ligands. We found that five oxygen atoms served as oxo bridges linking the five metal atoms, and that four water molecules were bound to the Mn(4)CaO(5) cluster; some of them may therefore serve as substrates for dioxygen formation. We identified more than 1,300 water molecules in each photosystem II monomer. Some of them formed extensive hydrogen-bonding networks that may serve as channels for protons, water or oxygen molecules. The determination of the high-resolution structure of photosystem II will allow us to analyse and understand its functions in great detail. en-copyright= kn-copyright= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KamiyaNobuo en-aut-sei=Kamiya en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University affil-num=2 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=3 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science; Okayama University affil-num=4 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University END start-ver=1.4 cd-journal=joma no-vol=104 cd-vols= no-issue=1-2 article-no= start-page=9 end-page=18 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=2011 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of the catalytic, inorganic core of oxygen-evolving photosystem II at 1.9 ? resolution en-subtitle= kn-subtitle= en-abstract= kn-abstract=The catalytic center for photosynthetic water-splitting consists of 4 Mn atoms and 1 Ca atom and is located near the lumenal surface of photosystem II. So far the structure of the Mn(4)Ca-cluster has been studied by a variety of techniques including X-ray spectroscopy and diffraction, and various structural models have been proposed. However, its exact structure is still unknown due to the limited resolution of crystal structures of PSII achieved so far, as well as possible radiation damages that might have occurred. Very recently, we have succeeded in solving the structure of photosystem II at 1.9 angstrom. which yielded a detailed picture of the Mn(4)CaO(5)-cluster for the first time. In the high resolution structure, the Mn(4)CaO(5)-cluster is arranged in a distorted chair form, with a cubane-like structure formed by 3 Mn and 1 Ca, 4 oxygen atoms as the distorted base of the chair, and 1 Mn and 1 oxygen atom outside of the cubane as the back of the chair. In addition, four water molecules were associated with the cluster, among which, two are associated with the terminal Mn atom and two are associated with the Ca atom. Some of these water molecules may therefore serve as the substrates for water-splitting. The high resolution structure of the catalytic center provided a solid basis for elucidation of the mechanism of photosynthetic water splitting. We review here the structural features of the Mn(4)CaO(5)-cluster analyzed at 1.9 angstrom resolution, and compare them with the structures reported previously. en-copyright= kn-copyright= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KamiyaNobuo en-aut-sei=Kamiya en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, and The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University affil-num=2 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, and The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University affil-num=3 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, and The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University affil-num=4 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University en-keyword=Crystal structure kn-keyword=Crystal structure en-keyword=Membrane protein structure kn-keyword=Membrane protein structure en-keyword=Oxygen-evolving complex kn-keyword=Oxygen-evolving complex en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=Water-oxidation kn-keyword=Water-oxidation END start-ver=1.4 cd-journal=joma no-vol=1807 cd-vols= no-issue=3 article-no= start-page=319 end-page=325 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=201103 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Roles of PsbI and PsbM in photosystem II dimer formation and stability studied by deletion mutagenesis and X-ray crystallography en-subtitle= kn-subtitle= en-abstract= kn-abstract=PsbM and PsbI are two low molecular weight subunits of photosystem II (PSII), with PsbM being located in the center, and PsbI in the periphery, of the PSII dimer. In order to study the functions of these two subunits from a structural point of view, we crystallized and analyzed the crystal structure of PSII dimers from two mutants lacking either PsbM or PsbI. Our results confirmed the location of these two subunits in the current crystal structure, as well as their absence in the respective mutants. The relative contents of PSII dimers were found to be decreased in both mutants, with a concomitant increase in the amount of PSII monomers, suggesting a destabilization of PSII dimers in both of the mutants. On the other hand, the accumulation level of the overall PSII complexes in the two mutants was similar to that in the wild-type strain. Treatment of purified PSII dimers with lauryldimethylamine N-oxide at an elevated temperature preferentially disintegrated the dimers from the PsbM deletion mutant into monomers and CP43-less monomers, whereas no significant degradation of the dimers was observed from the PsbI deletion mutant. These results indicate that although both PsbM and PsbI are required for the efficient formation and stability of PSII dimers in vivo, they have different roles, namely, PsbM is required directly for the formation of dimers and its absence led to the instability of the dimers accumulated. On the other hand, PsbI is required in the assembly process of PSII dimers in vivo; once the dimers are formed, PsbI was no longer required for its stability. en-copyright= kn-copyright= en-aut-name=KawakamiKeisuke en-aut-sei=Kawakami en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=UmenaYasufumi en-aut-sei=Umena en-aut-mei=Yasufumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IwaiMasako en-aut-sei=Iwai en-aut-mei=Masako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KawabataYousuke en-aut-sei=Kawabata en-aut-mei=Yousuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=IkeuchiMasahiko en-aut-sei=Ikeuchi en-aut-mei=Masahiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KamiyaNobuo en-aut-sei=Kamiya en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University affil-num=2 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University affil-num=3 en-affil= kn-affil=Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science affil-num=4 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University affil-num=5 en-affil= kn-affil=Department of Life Sciences (Biology), Graduate School of Arts and Science, The University of Tokyo affil-num=6 en-affil= kn-affil=Department of Chemistry, Graduate School of Science, Osaka City University affil-num=7 en-affil= kn-affil=Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University en-keyword=Photosystem II kn-keyword=Photosystem II en-keyword=Mutant kn-keyword=Mutant en-keyword=Crystal structure kn-keyword=Crystal structure en-keyword=PsbM kn-keyword=PsbM en-keyword=PsbI kn-keyword=PsbI en-keyword=Oxygen evolution kn-keyword=Oxygen evolution END