Photosynthetic water oxidation: Binding and activation of substrate waters for O-O bond formation
© 2015 The Royal Society of Chemistry. Photosynthetic water oxidation occurs at the oxygen-evolving complex (OEC) of Photosystem II (PSII). The OEC, which contains a Mn4CaO5 inorganic cluster ligated by oxides, waters and amino-acid residues, cycles through five redox intermediates known as Si states (i = 0-4). The electronic and structural properties of the transient S4 intermediate that forms the O-O bond are not well understood. In order to gain insight into how water is activated for O-O bond formation in the S4 intermediate, we have performed a detailed analysis of S-state dependent substrate water binding kinetics taking into consideration data from Mn coordination complexes. This analysis supports a model in which the substrate waters are both bound as terminal ligands and react via a water-nucleophile attack mechanism.
Publication Source (Journal or Book title)
Vinyard, D., Khan, S., & Brudvig, G. (2015). Photosynthetic water oxidation: Binding and activation of substrate waters for O-O bond formation. Faraday Discussions, 185, 37-50. https://doi.org/10.1039/c5fd00087d