Probing the role of Valine 185 of the D1 protein in the Photosystem II oxygen evolution |
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Authors: | Miwa Sugiura Tania Tibiletti Itsuki Takachi Yuya Hara Shin Kanawaku Julien Sellés Alain Boussac |
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Affiliation: | 1. Proteo-Science Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan;2. 2;3. Société Civile Synchrotron SOLEIL, L''Orme des Merisiers, 91192 Gif-sur-Yvette, France;4. Graduate School of Science and Technology, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan;5. Institut de Biologie Physico-Chimique, UMR CNRS 7141 and Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France |
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Abstract: | In Photosystem II (PSII), the Mn4CaO5-cluster of the active site advances through five sequential oxidation states (S0 to S4) before water is oxidized and O2 is generated. The V185 of the D1 protein has been shown to be an important amino acid in PSII function (Dilbeck et al. Biochemistry 52 (2013) 6824–6833). Here, we have studied its role by making a V185T site-directed mutant in the thermophilic cyanobacterium Thermosynechococcus elongatus. The properties of the V185T-PSII have been compared to those of the WT*3-PSII by using EPR spectroscopy, polarography, thermoluminescence and time-resolved UV–visible absorption spectroscopy. It is shown that the V185 and the chloride binding site very likely interact via the H-bond network linking TyrZ and the halide. The V185 contributes to the stabilization of S2 into the low spin (LS), S?=?1/2, configuration. Indeed, in the V185T mutant a high proportion of S2 exhibits a high spin (HS), S?=?5/2, configuration. By using bromocresol purple as a dye, a proton release was detected in the S1TyrZ | |
Keywords: | MES CHES Chl chlorophyll D1 Accessory Chl on the D1 or D2 side, respectively DCBQ DCMU 3-(3,4-Dichlorophenyl)-1,1-dimethylurea DMSO Dimethyl sulfoxide HEPES 2-[4-(2-Hydroxyethyl)-1-piperazinyl] ethanesulfonic acid HS high spin LS low spin MES 680 Primary electron donor D1 D1 pheophytin on the D1 or D2 side, respectively PPBQ PSII Photosystem II 680 chlorophyll dimer acting as the electron donor A primary quinone acceptor B Secondary quinone acceptor 2 2 D redox active tyrosine 160 of D2 Z redox active tyrosine 161 of D1 WT*3 43-H EPR Electron Paramagnetic Resonance ENDOR Electron Nuclear Double Resonance DFT Density functional theory XFEL X-ray free-electron laser Photosystem II Oxygen evolution 4 Spin state Proton release |
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