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- Title
Water Molecules Gating a Photoinduced One‐Electron Two‐Protons Transfer in a Tyrosine/Histidine (Tyr/His) Model of Photosystem II.
- Authors
Chararalambidis, Georgios; Das, Shyamal; Trapali, Adelais; Quaranta, Annamaria; Orio, Maylis; Halime, Zakaria; Fertey, Pierre; Guillot, Régis; Coutsolelos, Athanassios; Leibl, Winfried; Aukauloo, Ally; Sircoglou, Marie
- Abstract
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.
- Subjects
PHOTOSYSTEMS; FLASH photolysis; RADICAL cations; HISTIDINE; TYROSINE; ELECTROPHILES
- Publication
Angewandte Chemie, 2018, Vol 130, Issue 29, p9151
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.201804498