Studies on the oxygen-evolving reaction mechanism of photosystem II at an atomic resolution

2017 Fiscal Year Final Research Report

• Project/Area Number: 24227002
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Structural biochemistry
• Research Institution: Osaka City University
• Principal Investigator: Kamiya Nobuo 大阪市立大学, 複合先端研究機構, 教授 (60152865)
• Co-Investigator(Kenkyū-buntansha): 八ツ橋 知幸 大阪市立大学, 大学院理学研究科, 教授 (70305613)
• Co-Investigator(Renkei-kenkyūsha): KAWAKAMI KEISUKE 大阪市立大学, 複合先端研究機構, 特任准教授 (40619904) ; UMENA YASUFUMI 大阪市立大学, 複合先端研究機構, 特任准教授 (10468267) ; Fukushima Yoshimasa 大阪市立大学, 複合先端研究機構, 特任講師 (00402438) ; Noji Tomoyasu 大阪市立大学, 複合先端研究機構, 特任講師 (40452205)
• Project Period (FY): 2012-05-31 – 2017-03-31
• Keywords: 光化学系II / 光合成 / 水分解酸素発生機構 / X線結晶構造解析 / Mn4Caクラスター / Mn原子混合原子価 / Kokサイクル / 人工光合成

Outline of Final Research Achievements

We have reported the high-resolution structure of photosystem II (PSII), which is evolving oxygen from water molecules in photosynthesis, at 1.9 A in 2011. The structure involves the oxygen-evolving Mn-cluster at the most stable Kok’s S1 state. In order to understand the oxygen-evolving mechanism of PSII, activated structures of PSII should be resolved. In this study, we determined many structures of PSII crystals; four of complexes with herbicides, one of PsbM-subunit deleted mutant, two of ion-substituted derivatives from chloride to bromide or iodide, and so on. By studying intermediate states, S0 and S2, in the Kok cycle, new knowledge on the oxygen-evolving mechanism of PSII was obtained.

Free Research Field

構造生物化学、タンパク質結晶学