title: A model of the oxygen-evolving center of photosystem II predicted by structural refinement based on EXAFS simulations.
abstract: A refined computational structural model of the oxygen-evolving complex (OEC) of photosystem II (PSII) is introduced. The model shows that the cuboidal core Mn3CaO4 with a "dangler" Mn ligated to a corner mu4-oxide ion is maximally consistent with the positioning of the amino acids around the metal cluster as characterized by XRD models and high-resolution spectroscopic data, including polarized EXAFS of oriented single crystals and isotropic EXAFS. It is, therefore, natural to expect that the proposed structural model should be particularly useful to establish the structure of the OEC, consistently with high-resolution spectroscopic data, and for elucidating the mechanism of water-splitting in PSII as described by the intermediate oxidation states of the EC along the catalytic cycle.
authors.affiliation: Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, USA.
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Sproviero
authors.forename: José A
authors.initials: JA
authors.lastname: Gascón
authors.forename: James P
authors.initials: JP
authors.lastname: McEvoy
authors.forename: Gary W
authors.initials: GW
authors.lastname: Brudvig
authors.forename: Victor S
authors.initials: VS
authors.lastname: Batista
mesh_terms: D002118:Calcium / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D008345:Manganese / Q000737:chemistry; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D011789:Quantum Theory; D013052:Spectrometry, X-Ray Emission
chemical_list: D045332:Photosystem II Protein Complex; D008345:Manganese; D010100:Oxygen; D002118:Calcium