title: Regulated Electron Tunneling of Photoinduced Primary Charge-Separated State in the Photosystem II Reaction Center.
abstract: In initial events of the photosynthesis by higher plants, the photosystem II (PSII) generates photoinduced primary charge-separated (CS) state composed of reduced pheophytin (PheoD1-•) and oxidized special pair (P+•) in chlorophyll a (Chla) PD1/PD2in the D1/D2 heterodimer, ultimately leading to the water oxidation at the oxygen-evolving Mn4CaO5cluster by P+•. To understand the mechanism of the efficient generation of initially localized CS state (PD1+•PheoD1-•), we have characterized cofactor geometries and electronic coupling of the photoinduced primary CS state in quinone prereduced membrane of PSII from spinach using the time-resolved electron paramagnetic resonance method. It has been revealed that the electronic coupling between the charges is significantly weak in the CS state separated by 1.5 nm, showing the importance of regulated cofactor-cofactor electronic interaction between a vinyl substituent in PheoD1and an accessory chlorophyll to inhibit the energy-wasting charge recombination after the primary electron-transfer processes.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Division of Materials Science (Physics), Graduate School of Science, Nagoya University , Furocho, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nagashima
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Reina
authors.initials: R
authors.lastname: Minobe
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.|Laser Molecular Photoscience Laboratory, Molecular Photoscience Research Center, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Takashi
authors.identifier: http://orcid.org/0000-0001-6465-5792
authors.initials: T
authors.lastname: Tachikawa
authors.affiliation: Division of Materials Science (Physics), Graduate School of Science, Nagoya University , Furocho, Chikusa, Nagoya 464-8602, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mino
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.|Laser Molecular Photoscience Laboratory, Molecular Photoscience Research Center, Kobe University , 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Yasuhiro
authors.identifier: http://orcid.org/0000-0001-8370-9362
authors.initials: Y
authors.lastname: Kobori
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D010084:Oxidation-Reduction; D010100:Oxygen; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018724:Spinacia oleracea / Q000378:metabolism
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D010100:Oxygen; D000077194:Chlorophyll A