title: Oxygen-evolving Mn cluster in photosystem II: the protonation pattern and oxidation state in the high-resolution crystal structure.
abstract: Extensive quantum chemical DFT calculations were performed on the high-resolution (1.9 Å) crystal structure of photosystem II in order to determine the protonation pattern and the oxidation states of the oxygen-evolving Mn cluster. First, our data suggest that the experimental structure is not in the S(1)-state. Second, a rather complete set of possible protonation patterns is studied, resulting in very few alternative protonation patterns whose relevance is discussed. Finally, we show that the experimental structure is a mixture of states containing highly reduced forms, with the largest contribution (almost 60%) from the S(-3)-state, Mn(II,II,III,III).
authors.affiliation: Department of Biology, Chemistry and Pharmacy, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany.
authors.forename: Artur
authors.initials: A
authors.lastname: Galstyan
authors.forename: Arturo
authors.initials: A
authors.lastname: Robertazzi
authors.forename: Ernst Walter
authors.initials: EW
authors.lastname: Knapp
mesh_terms: D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory
chemical_list: D045332:Photosystem II Protein Complex; D011522:Protons; D008345:Manganese; D010100:Oxygen