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=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=13 cd-vols= no-issue=1 article-no= start-page=1679 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220330 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of a tetrameric photosystem I from a glaucophyte alga Cyanophora paradoxa en-subtitle= kn-subtitle= en-abstract= kn-abstract=Photosystem I (PSI) is one of the two photosystems functioning in light-energy harvesting, transfer, and electron transfer in photosynthesis. However, the oligomerization state of PSI is variable among photosynthetic organisms. We present a 3.8-angstrom resolution cryo-electron microscopic structure of tetrameric PSI isolated from the glaucophyte alga Cyanophora paradoxa, which reveals differences with PSI from other organisms in subunit composition and organization. The PSI tetramer is organized in a dimer of dimers with a C2 symmetry. Unlike cyanobacterial PSI tetramers, two of the four monomers are rotated around 90 degrees, resulting in a completely different pattern of monomer-monomer interactions. Excitation-energy transfer among chlorophylls differs significantly between Cyanophora and cyanobacterial PSI tetramers. These structural and spectroscopic features reveal characteristic interactions and excitation-energy transfer in the Cyanophora PSI tetramer, suggesting that the Cyanophora PSI could represent a turning point in the evolution of PSI from prokaryotes to eukaryotes. 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=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=UenoYoshifumi en-aut-sei=Ueno en-aut-mei=Yoshifumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 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=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=Tian-YiJiang en-aut-sei=Tian-Yi en-aut-mei=Jiang 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=Jian-RenShen en-aut-sei=Jian-Ren en-aut-mei=Shen 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 Science, Kobe University kn-affil= affil-num=4 en-affil=Institute of Low Temperature Science, Hokkaido University kn-affil= affil-num=5 en-affil=Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science 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=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=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=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