Redox potential of the oxygen-evolving complex

• Project Area: Creation of novel light energy conversion system through elucidation of the molecular mechanism of photosynthesis and its artificial design in terms of time and space
• Project/Area Number: 20H05090
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Complex systems
• Research Institution: The University of Tokyo
• Principal Investigator: 石北 央 東京大学, 先端科学技術研究センター, 教授 (00508111)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2021: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2020: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 人工光合成 / 電子移動 / 水分解酸素発生 / 光化学系II / プロトン共役電子移動 / 酸化還元電位

Outline of Research at the Start

PSIIにおけるMn4CaO5の電位は報告されていない。ましてや各S状態における各Mnサイトの電位は不明である。分子の1電子酸化の電位は、分子からの1電子放出に対応、すなわち最高被占軌道のレベルに対応することがよく知られている。本研究では「電子の流れ」と「プロトンの流れ」の両面からの整合性から水分解反応機構を明らかにする。

Outline of Annual Research Achievements

植物などが行う天然光合成における水分解酸素発生反応は蛋白質photosystem II (PSII)で行われる。本研究では、最近の結晶構造で明らかにされたMn4CaO5近傍の水分子挙動および水分解に関わる電子移動経路のコファクターのエナジェティクスをも分子化学的に解明した（Mandal et al. J. Phys. Chem. Lett. 2020; Mandal et al. J. Phys. Chem. Lett. 2021）。水分解反応に重要であるものの酸化還元活性がないCa2+イオン（Saito et al. Biochemistry 2020）やCl-イオン（Mandal et al. J. Phys. Chem. B 2022）に関しても、その意義を明らかにした。さらに、H+移動経路に関わると考えられるアミノ酸変異体を実験研究との共同研究で100種類以上解析し、プロトン移動に関わる重要なアミノ酸残基を同定した（Kuroda et al. Biochim. Biophys. Acta (Bioenergetics) 2021）。
光誘起・電荷分離反応が起こることで水分解反応は駆動されるが、そこに関わるクロロフィルやフェ尾フィティンを含めたでな分離状態のエナジェティクス（Tamura et al. Proc. Natl. Acad. Sci. U. S. A. 2020）やダイナミクス（Tamura et al. Chem. Sci. 2021）を明らかにした。また、電荷分離状態を最終的に安定化させるキノンへの電子移動とプロトン移動の反応機構に関しても解明を行った（Saito et al. Phys. Chem. Chem. Phys. 2020; Sugo et al. Proc. Natl. Acad. Sci. U. S. A. 2021）。また

Research Progress Status

令和3年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和3年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] Structure-guided design enables development of a hyperpolarized molecular probe for the detection of aminopeptidase N activity in vivo (2022)
  • Author(s): Yutaro Saito, Hiroyuki Yatabe, Iori Tamura, Yohei Kondo, Ryo Ishida, Tomohiro Seki, Keita Hiraga, Akihiro Eguchi, Yoichi Takakusagi, Keisuke Saito, Nobu Oshima, Hiroshi Ishikita, Kazutoshi Yamamoto, Murali C. Krishna, Shinsuke Sando
  • Journal Title: Science advances Volume: 8 Issue: 13
  • DOI: 10.1126/sciadv.abj2667
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Mechanism of Mixed-Valence Fe^2.5+・・・Fe^2.5+ Formation in Fe₄S₄ Clusters in the Ferredoxin Binding Motif (2022)
  • Author(s): Kanda Tomoki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry B Volume: 126 Issue: 16 Pages: 3059-3066
  • DOI: 10.1021/acs.jpcb.2c01320
  • Peer Reviewed / Open Access
• [Journal Article] Absorption wavelength along chromophore low-barrier hydrogen bonds (2022)
  • Author(s): Tsujimura Masaki、Tamura Hiroyuki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: iScience Volume: 25 Issue: 5 Pages: 104247-104247
  • DOI: 10.1016/j.isci.2022.104247
  • Peer Reviewed / Open Access
• [Journal Article] Mechanism of absorption wavelength shifts in anion channelrhodopsin-1 mutants (2021)
  • Author(s): Tsujimura Masaki、Noji Tomoyasu、Saito Keisuke、Kojima Keiichi、Sudo Yuki、Ishikita Hiroshi
  • Journal Title: Biochimica et Biophysica Acta (BBA) - Bioenergetics Volume: 1862 Issue: 2 Pages: 148349-148349
  • DOI: 10.1016/j.bbabio.2020.148349
  • Peer Reviewed / Open Access
• [Journal Article] Proton transfer pathway from the oxygen-evolving complex in photosystem II substantiated by extensive mutagenesis (2021)
  • Author(s): Kuroda Hiroshi、Kawashima Keisuke、Ueda Kazuyo、Ikeda Takuya、Saito Keisuke、Ninomiya Ryo、Hida Chisato、Takahashi Yuichiro、Ishikita Hiroshi
  • Journal Title: Biochimica et Biophysica Acta (BBA) - Bioenergetics Volume: 1862 Issue: 1 Pages: 148329-148329
  • DOI: 10.1016/j.bbabio.2020.148329
  • Peer Reviewed / Open Access
• [Journal Article] Identification of intermediate conformations in the photocycle of the light-driven sodium-pumping rhodopsin KR2 (2021)
  • Author(s): Tsujimura Masaki、Ishikita Hiroshi
  • Journal Title: Journal of Biological Chemistry Volume: 296 Pages: 100459-100459
  • DOI: 10.1016/j.jbc.2021.100459
  • Peer Reviewed / Open Access
• [Journal Article] Nature of Asymmetric Electron Transfer in the Symmetric Pathways of Photosystem I (2021)
  • Author(s): Mitsuhashi Koji、Tamura Hiroyuki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry B Volume: 125 Issue: 11 Pages: 2879-2885
  • DOI: 10.1021/acs.jpcb.0c10885
  • Peer Reviewed / Open Access
• [Journal Article] Two Distinct Oxygen-Radical Conformations in the X-ray Free Electron Laser Structures of Photosystem II (2021)
  • Author(s): Mandal Manoj、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 12 Issue: 16 Pages: 4032-4037
  • DOI: 10.1021/acs.jpclett.1c00814
  • Peer Reviewed / Open Access
• [Journal Article] The origin of unidirectional charge separation in photosynthetic reaction centers: nonadiabatic quantum dynamics of exciton and charge in pigment?protein complexes (2021)
  • Author(s): Tamura Hiroyuki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: Chemical Science Volume: 12 Issue: 23 Pages: 8131-8140
  • DOI: 10.1039/d1sc01497h
  • Peer Reviewed / Open Access
• [Journal Article] Role of redox-inactive metals in controlling the redox potential of heterometallic manganese?oxido clusters (2021)
  • Author(s): Saito Keisuke、Nakagawa Minesato、Mandal Manoj、Ishikita Hiroshi
  • Journal Title: Photosynthesis Research Volume: 148 Issue: 3 Pages: 153-159
  • DOI: 10.1007/s11120-021-00846-y
  • Peer Reviewed / Open Access
• [Journal Article] Mechanism of the formation of proton transfer pathways in photosynthetic reaction centers (2021)
  • Author(s): Sugo Yu、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 118 Issue: 30
  • DOI: 10.1073/pnas.2103203118
  • Peer Reviewed / Open Access
• [Journal Article] Electron Acceptor?Donor Iron Sites in the Iron?Sulfur Cluster of Photosynthetic Electron-Transfer Pathways (2021)
  • Author(s): Kanda Tomoki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 12 Issue: 31 Pages: 7431-7438
  • DOI: 10.1021/acs.jpclett.1c01896
  • Peer Reviewed / Open Access
• [Journal Article] Structural basis for high selectivity of a rice silicon channel Lsi1 (2021)
  • Author(s): Saitoh Yasunori、Mitani-Ueno Namiki、Saito Keisuke、Matsuki Kengo、Huang Sheng、Yang Lingli、Yamaji Naoki、Ishikita Hiroshi、Shen Jian-Ren、Ma Jian Feng、Suga Michihiro
  • Journal Title: Nature Communications Volume: 12 Issue: 1 Pages: 6236-6245
  • DOI: 10.1038/s41467-021-26535-x
  • NAID: 120007170514
  • Peer Reviewed / Open Access
• [Journal Article] Exploring the Retinal Binding Cavity of Archaerhodopsin-3 by Replacing the Retinal Chromophore With a Dimethyl Phenylated Derivative (2021)
  • Author(s): Tsuneishi Taichi、Takahashi Masataka、Tsujimura Masaki、Kojima Keiichi、Ishikita Hiroshi、Takeuchi Yasuo、Sudo Yuki
  • Journal Title: Frontiers in Molecular Biosciences Volume: 8 Pages: 794948-794948
  • DOI: 10.3389/fmolb.2021.794948
  • NAID: 120007183231
  • Peer Reviewed / Open Access
• [Journal Article] Proton transfer pathway in anion channelrhodopsin-1 (2021)
  • Author(s): Tsujimura Masaki、Kojima Keiichi、Kawanishi Shiho、Sudo Yuki、Ishikita Hiroshi
  • Journal Title: eLife Volume: 10
  • DOI: 10.7554/elife.72264
  • NAID: 120007183236
  • Peer Reviewed / Open Access
• [Journal Article] Long-Range Electron Tunneling from the Primary to Secondary Quinones in Photosystem II Enhanced by Hydrogen Bonds with a Nonheme Fe Complex (2021)
  • Author(s): Tamura Hiroyuki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry B Volume: 125 Issue: 49 Pages: 13460-13466
  • DOI: 10.1021/acs.jpcb.1c09538
  • Peer Reviewed / Open Access
• [Journal Article] Requirement of Chloride for the Downhill Electron Transfer Pathway from the Water-Splitting Center in Natural Photosynthesis (2021)
  • Author(s): Mandal Manoj、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry B Volume: 126 Issue: 1 Pages: 123-131
  • DOI: 10.1021/acs.jpcb.1c09176
  • Peer Reviewed / Open Access
• [Journal Article] Insights into the Protein Functions and Absorption Wavelengths of Microbial Rhodopsins (2020)
  • Author(s): Tsujimura Masaki、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry B Volume: 124 Issue: 52 Pages: 11819-11826
  • DOI: 10.1021/acs.jpcb.0c08910
  • Peer Reviewed / Open Access
• [Journal Article] The Nature of the Short Oxygen?Oxygen Distance in the Mn4CaO6 Complex of Photosystem II Crystals (2020)
  • Author(s): Mandal Manoj、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 11 Issue: 23 Pages: 10262-10268
  • DOI: 10.1021/acs.jpclett.0c02868
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways (2020)
  • Author(s): Saito Keisuke、Mandal Manoj、Ishikita Hiroshi
  • Journal Title: Physical Chemistry Chemical Physics Volume: 22 Issue: 44 Pages: 25467-25473
  • DOI: 10.1039/d0cp04265j
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Dependence of the chlorophyll wavelength on the orientation of a charged group: Why does the accessory chlorophyll have a low site energy in photosystem II? (2020)
  • Author(s): Saito Keisuke、Mitsuhashi Koji、Ishikita Hiroshi
  • Journal Title: Journal of Photochemistry and Photobiology A: Chemistry Volume: 402 Pages: 112799-112799
  • DOI: 10.1016/j.jphotochem.2020.112799
  • Peer Reviewed / Open Access
• [Journal Article] Green-Sensitive, Long-Lived, Step-Functional Anion Channelrhodopsin-2 Variant as a High-Potential Neural Silencing Tool (2020)
  • Author(s): Kojima Keiichi、Miyoshi Natsuki、Shibukawa Atsushi、Chowdhury Srikanta、Tsujimura Masaki、Noji Tomoyasu、Ishikita Hiroshi、Yamanaka Akihiro、Sudo Yuki
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 11 Issue: 15 Pages: 6214-6218
  • DOI: 10.1021/acs.jpclett.0c01406
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Energetics of Ionized Water Molecules in the H-Bond Network near the Ca2+ and Cl? Binding Sites in Photosystem II (2020)
  • Author(s): Saito Keisuke、Mandal Manoj、Ishikita Hiroshi
  • Journal Title: Biochemistry Volume: 59 Issue: 35 Pages: 3216-3224
  • DOI: 10.1021/acs.biochem.0c00177
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] pKa of the ligand water molecules in the oxygen-evolving Mn4CaO5 cluster in photosystem II (2020)
  • Author(s): Saito Keisuke、Nakagawa Minesato、Ishikita Hiroshi
  • Journal Title: Communications Chemistry Volume: 3 Issue: 1 Pages: 89-89
  • DOI: 10.1038/s42004-020-00336-7
  • Peer Reviewed / Open Access
• [Journal Article] Rigidly hydrogen-bonded water molecules facilitate proton transfer in photosystem II (2020)
  • Author(s): Sakashita Naoki、Ishikita Hiroshi、Saito Keisuke
  • Journal Title: Physical Chemistry Chemical Physics Volume: 22 Issue: 28 Pages: 15831-15841
  • DOI: 10.1039/d0cp00295j
  • Peer Reviewed / Open Access
• [Journal Article] Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers (2020)
  • Author(s): Tamura Hiroyuki、Saito Keisuke、Ishikita Hiroshi
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 117 Issue: 28 Pages: 16373-16382
  • DOI: 10.1073/pnas.2000895117
  • Peer Reviewed / Open Access
• [Journal Article] Quenching of Singlet Oxygen by Carotenoids via Ultrafast Superexchange Dynamics (2020)
  • Author(s): Tamura Hiroyuki、Ishikita Hiroshi
  • Journal Title: The Journal of Physical Chemistry A Volume: 124 Issue: 25 Pages: 5081-5088
  • DOI: 10.1021/acs.jpca.0c02228
  • Peer Reviewed