title: Where plants make oxygen: a structural model for the photosynthetic oxygen-evolving manganese cluster.
abstract: In the photosynthetic evolution of oxygen, water oxidation occurs at a catalytic site that includes four manganese atoms together with the essential cofactors, the calcium and chlorine ions. A structural model and a determination of the manganese oxidation states based on x-ray absorption spectroscopy are presented. The salient features, in both higher plants and cyanobacteria, are a pair of di-mu-oxo bridged manganese binuclear clusters linked by a mono-mu-oxo bridge, one proximal calcium atom, and one halide. In dark-adapted samples, manganese occurs in oxidation states (III) and (IV). Data from oriented membranes display distinct dichroism, precluding highly symmetrical structures for the manganese complex.
authors: Structural Biology Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
authors: V K
authors: VK
authors: Yachandra
authors: V J
authors: VJ
authors: DeRose
authors: M J
authors: MJ
authors: Latimer
authors: I
authors: I
authors: Mukerji
authors: K
authors: K
authors: Sauer
authors: M P
authors: MP
authors: Klein
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002712:Chlorides / Q000737:chemistry / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism; D005459:Fluorides / Q000737:chemistry / Q000378:metabolism; D005583:Fourier Analysis; D008345:Manganese / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D010944:Plants / Q000378:metabolism; D011188:Potassium / Q000737:chemistry / Q000378:metabolism; D013057:Spectrum Analysis
chemical_list: D001952:Bridged-Ring Compounds; D002712:Chlorides; D045322:Photosynthetic Reaction Center Complex Proteins; D008345:Manganese; D005459:Fluorides; D011188:Potassium; D010100:Oxygen; D002118:Calcium