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-Structure paper
タイトル | Structure of Photosystem II Reveals Protective Mechanisms against Environmental Stress. |
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ジャーナル・号・ページ | Cells, Vol. 12, Issue 15, Year 2023 |
掲載日 | 2023年7月31日 |
著者 | Maria Fadeeva / Daniel Klaiman / Ido Caspy / Nathan Nelson / |
PubMed 要旨 | Green alga is known for its ability to carry out photosynthesis under harsh conditions. Using cryogenic electron microscopy (cryoEM), we obtained a high-resolution structure of PSII at 2.72 Å. This ...Green alga is known for its ability to carry out photosynthesis under harsh conditions. Using cryogenic electron microscopy (cryoEM), we obtained a high-resolution structure of PSII at 2.72 Å. This structure revealed 64 subunits, which encompassed 386 chlorophylls, 86 carotenoids, four plastoquinones, and several structural lipids. At the luminal side of PSII, a unique subunit arrangement was observed to protect the oxygen-evolving complex. This arrangement involved PsbO (OEE1), PsbP (OEE2), PsbB, and PsbU (a homolog of plant OEE3). PsbU interacted with PsbO, PsbC, and PsbP, thereby stabilizing the shield of the oxygen-evolving complex. Significant changes were also observed at the stromal electron acceptor side. PsbY, identified as a transmembrane helix, was situated alongside PsbF and PsbE, which enclosed cytochrome . Supported by the adjacent C-terminal helix of Psb10, these four transmembrane helices formed a bundle that shielded cytochrome from the surrounding solvent. Moreover, the bulk of Psb10 formed a protective cap, which safeguarded the quinone site and likely contributed to the stacking of PSII complexes. Based on our findings, we propose a protective mechanism that prevents Q (plastoquinone B) from becoming fully reduced. This mechanism offers insights into the regulation of electron transfer within PSII. |
リンク | Cells / PubMed:37566050 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.73 Å |
構造データ | EMDB-15973, PDB-8bd3: |
化合物 | ChemComp-CHL: ChemComp-CLA: ChemComp-LUT: ChemComp-LHG: ChemComp-LMG: ChemComp-RRX: ChemComp-NEX: ChemComp-XAT: ChemComp-SQD: ChemComp-OEX: ChemComp-FE2: ChemComp-CL: ChemComp-PHO: ChemComp-BCR: ChemComp-PL9: ChemComp-DGD: ChemComp-BCT: ChemComp-HEM: ChemComp-LMU: ChemComp-HOH: |
由来 |
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キーワード | PHOTOSYNTHESIS / Green alga / PSII / C.ohadi / membrane protein / Cryo-EM |