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=298 cd-vols= no-issue=12 article-no= start-page=102668 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=202212 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Crystal structures of photosystem II from a cyanobacterium expressing psbA2 in comparison to psbA3 reveal differences in the D1 subunit en-subtitle= kn-subtitle= en-abstract= kn-abstract=Three psbA genes (psbA1, psbA2, and psbA3) encoding the D1 subunit of photosystem II (PSII) are present in the ther-mophilic cyanobacterium Thermosynechococcus elongatus and are expressed differently in response to changes in the growth environment. To clarify the functional differences of the D1 protein expressed from these psbA genes, PSII dimers from two strains, each expressing only one psbA gene (psbA2 or psbA3), were crystallized, and we analyzed their structures at resolu-tions comparable to previously studied PsbA1-PSII. Our results showed that the hydrogen bond between pheophytin/D1 (PheoD1) and D1-130 became stronger in PsbA2-and PsbA3-PSII due to change of Gln to Glu, which partially explains the increase in the redox potential of PheoD1 observed in PsbA3. In PsbA2, one hydrogen bond was lost in PheoD1 due to the change of D1-Y147F, which may explain the decrease in stability of PheoD1 in PsbA2. Two water molecules in the Cl-1 channel were lost in PsbA2 due to the change of D1-P173M, leading to the narrowing of the channel, which may explain the lower efficiency of the S-state transition beyond S2 in PsbA2-PSII. In PsbA3-PSII, a hydrogen bond between D1-Ser270 and a sulfoquinovosyl-diacylglycerol molecule near QB dis-appeared due to the change of D1-Ser270 in PsbA1 and PsbA2 to D1-Ala270. This may result in an easier exchange of bound QB with free plastoquinone, hence an enhancement of oxygen evolution in PsbA3-PSII due to its high QB exchange efficiency. These results provide a structural basis for further functional examination of the three PsbA variants. en-copyright= kn-copyright= en-aut-name=NakajimaYoshiki en-aut-sei=Nakajima en-aut-mei=Yoshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Ugai-AmoNatsumi en-aut-sei=Ugai-Amo en-aut-mei=Natsumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ToneNaoki en-aut-sei=Tone en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NakagawaAkiko en-aut-sei=Nakagawa en-aut-mei=Akiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 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=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=SugiuraMiwa en-aut-sei=Sugiura en-aut-mei=Miwa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 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=8 ORCID= en-aut-name=Jian-RenShen en-aut-sei=Jian-Ren en-aut-mei=Shen kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Proteo-Science Research Center, Ehime University kn-affil= affil-num=5 en-affil=Graduate School and College of Arts and Sciences, The University of Tokyo kn-affil= affil-num=6 en-affil=Graduate School and College of Arts and Sciences, The University of Tokyo kn-affil= affil-num=7 en-affil=Proteo-Science Research Center, Ehime University kn-affil= affil-num=8 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science, Okayama 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=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 Å 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=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=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