title: Coordination sphere and structure of the Mn cluster of the oxygen-evolving complex in photosynthetic organisms.
abstract: The great similarity between the binding of Fe(II) and the high-affinity Mn-binding site in the Mn-depleted PSII membranes (Semin et al. (1996) FEBS Lett. 375, 223-226) suggests that the coordination sphere of Mn in PSII is also suitable for iron. A comparison is performed between the primary amino acid sequences of D1 and D2 and diiron-oxo enzymes with the function of oxygen activation. All conservative motifs (EXXH) and residues binding and stabilizing the diiron cluster in diiron-oxo enzymes have been found in the C-terminal domains of D1 and D2 polypeptides. On the basis of these sequence similarities we suggest a structural model for the manganese cluster in the oxygen-evolving complex.
authors.affiliation: Biophysics Department, Biological Faculty, Moscow State University, Moscow, Russian Federation.
authors.forename: B K
authors.initials: BK
authors.lastname: Semin
authors.forename: F
authors.initials: F
authors.lastname: Parak
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D005296:Ferrous Compounds / Q000378:metabolism*; D006860:Hydrogen Bonding; D008024:Ligands; D008345:Manganese / Q000737:chemistry* / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism; D008956:Models, Chemical; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010100:Oxygen / Q000378:metabolism*; D010105:Oxygenases / Q000737:chemistry / Q000378:metabolism; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D012264:Ribonucleotide Reductases / Q000737:chemistry / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D005296:Ferrous Compounds; D008024:Ligands; D045322:Photosynthetic Reaction Center Complex Proteins; D014867:Water; D008345:Manganese; D006899:Mixed Function Oxygenases; D010105:Oxygenases; C021555:methane monooxygenase; C018747:acyl-(acyl-carrier-protein)desaturase; D012264:Ribonucleotide Reductases; D010100:Oxygen