title: Comparative Analysis of the Interaction of the Primary Quinone QAin Intact and Mn-Depleted Photosystem II Membranes Using Light-Induced ATR-FTIR Spectroscopy.
abstract: In photosystem II, redox potential Emof primary quinone QAshifts by approximately +150 mV upon inactivation of the Mn4CaO5cluster. Although this phenomenon is important in photoprotection, the molecular mechanism of the positive Em(QA-/QA) shift remains unclear. Here, we investigated the effect of Mn depletion on the interaction of QAusing light-induced ATR-FTIR spectroscopy. It was shown that Mn depletion hardly changed a QA-/QAFTIR difference spectrum, indicating that the H-bond interaction of QAand its immediate surroundings were virtually unchanged by Mn4CaO5cluster inactivation. On the basis of this result, a possible mechanism of the Em(QA-/QA) shift is discussed.
authors.affiliation: Division of Material Science, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Division of Material Science, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Ishii
authors.affiliation: Division of Material Science, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Noguchi
mesh_terms: D004579:Electron Transport; D008027:Light; D008345:Manganese / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011809:Quinones / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D018724:Spinacia oleracea / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D011809:Quinones; D008345:Manganese