Where plants make oxygen: a structural model for the photosynthetic oxygen-evolving manganese cluster.
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.
Yachandra
V K
VK
Structural Biology Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
DeRose
V J
VJ
Latimer
M J
MJ
Mukerji
I
I
Sauer
K
K
Klein
M P
MP
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
D001952:Bridged-Ring Compounds; D002712:Chlorides; D045322:Photosynthetic Reaction Center Complex Proteins; D008345:Manganese; D005459:Fluorides; D011188:Potassium; D010100:Oxygen; D002118:Calcium