title: Rationalising the geometric variation between the A and B monomers in the 1.9 Å crystal structure of photosystem II.
abstract: Density functional theory calculations are reported on a set of models of the water-oxidising complex (WOC) of photosystem II (PSII), exploring structural features revealed in the most recent (1.9 Å resolution) X-ray crystallographic studies of PSII. Crucially, we find that the variation in the Mn-Mn distances seen between the A and B monomers of this crystal structure can be entirely accounted for, in the low oxidation state (LOS) paradigm, by consideration of the interplay between two hydrogen-bonding interactions involving proximate amino acid residues with the oxo bridges of the WOC, that is, His337 with O3 (which leads to a general elongation in the Mn-Mn distances between Mn1, Mn2 and Mn3) and Arg357 with O2 (which results in a specific elongation of the Mn2-Mn3 distance).
authors.affiliation: Australian National University, Research School of Chemistry, Science Road, Canberra, 0200 (Australia), Tel.: 0061 2 61252934, Mobile: 0419440730, Fax: 0061 2 61250760.
authors.forename: Simon
authors.initials: S
authors.lastname: Petrie
authors.forename: Robert
authors.initials: R
authors.lastname: Stranger
authors.forename: Ron J
authors.initials: RJ
authors.lastname: Pace
mesh_terms: D001120:Arginine / Q000737:chemistry; D002118:Calcium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006639:Histidine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008345:Manganese / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D014443:Tyrosine / Q000737:chemistry
chemical_list: D045332:Photosystem II Protein Complex; D014443:Tyrosine; D008345:Manganese; D006639:Histidine; D001120:Arginine; D010100:Oxygen; D002118:Calcium
keywords: DFT; hydrogen bonding; manganese; photosynthesis; photosystem II