Volume 130, Issue 29 pp. 9151-9155
Zuschrift

Water Molecules Gating a Photoinduced One-Electron Two-Protons Transfer in a Tyrosine/Histidine (Tyr/His) Model of Photosystem II

Dr. Georgios Chararalambidis

Dr. Georgios Chararalambidis

Laboratory of Bioinorganic Chemistry, Chemistry Department, University of Crete, PO Box 2208, 71003 Heraklion, Crete, Greece

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Dr. Shyamal Das

Dr. Shyamal Das

Institut des Sciences du vivant Frédéric Joliot/Institut de Biologie Intégrative de la Cellule, UMR 9198, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 91191 Gif-sur-Yvette, France

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Adelais Trapali

Adelais Trapali

Laboratory of Bioinorganic Chemistry, Chemistry Department, University of Crete, PO Box 2208, 71003 Heraklion, Crete, Greece

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Dr. Annamaria Quaranta

Dr. Annamaria Quaranta

Institut des Sciences du vivant Frédéric Joliot/Institut de Biologie Intégrative de la Cellule, UMR 9198, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 91191 Gif-sur-Yvette, France

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Dr. Maylis Orio

Dr. Maylis Orio

Aix Marseille Univ, iSm2, CNRS, Cent Marseille, 13397 Marseille, France

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Dr. Zakaria Halime

Dr. Zakaria Halime

Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182 CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France

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Dr. Pierre Fertey

Dr. Pierre Fertey

Synchrotron SOLEIL, BP 48, L'Orme des Merisiers, Saint Aubin, 91192 Gif-sur-Yvette Cedex, France

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Dr. Régis Guillot

Dr. Régis Guillot

Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182 CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France

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Prof. Athanassios Coutsolelos

Corresponding Author

Prof. Athanassios Coutsolelos

Laboratory of Bioinorganic Chemistry, Chemistry Department, University of Crete, PO Box 2208, 71003 Heraklion, Crete, Greece

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Dr. Winfried Leibl

Corresponding Author

Dr. Winfried Leibl

Institut des Sciences du vivant Frédéric Joliot/Institut de Biologie Intégrative de la Cellule, UMR 9198, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 91191 Gif-sur-Yvette, France

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Prof. Ally Aukauloo

Corresponding Author

Prof. Ally Aukauloo

Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182 CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France

Institut des Sciences du vivant Frédéric Joliot/Institut de Biologie Intégrative de la Cellule, UMR 9198, CEA, CNRS, Université Paris Sud, Université Paris-Saclay, 91191 Gif-sur-Yvette, France

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Dr. Marie Sircoglou

Corresponding Author

Dr. Marie Sircoglou

Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182 CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France

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First published: 22 May 2018
Citations: 3

Abstract

We investigate a biomimetic model of a TyrZ/His190 pair, a hydrogen-bonded phenol/imidazole covalently attached to a porphyrin sensitizer. Laser flash photolysis in the presence of an external electron acceptor reveals the need for water molecules to unlock the light-induced oxidation of the phenol through an intramolecular pathway. Kinetics monitoring encompasses two fast phases with distinct spectral properties. The first phase is related to a one-electron transfer from the phenol to the porphyrin radical cation coupled with a domino two-proton transfer leading to the ejection of a proton from the imidazole–phenol pair. The second phase concerns conveying the released proton to the porphyrin N4 coordinating cavity. Our study provides an unprecedented example of a light-induced electron-transfer process in a TyrZ/His190 model of photosystem II, evidencing the movement of both the phenol and imidazole protons along an isoenergetic pathway.

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