Correlated behavior of the EPR signal of cytochrome b-559 heme Fe(III) ligated by OH- and the multiline signal of the Mn cluster in PS-II membrane fragments.
EPR signals of Cyt b-559 heme Fe(III) ligated by OH- and the multiline signal of the Mn cluster in PS-II membrane fragments have been investigated. In 2,3-dicyano-5,6-dichloro-p-benzoquinone-oxidized PS-II membrane fragments the light-induced decrease of the EPR signal of the heme Fe(III)-OH- is accompanied by the appearance of the EPR multiline signal of the Mn cluster. Addition of F- ions, which act as a stronger ligand for heme Fe(III) than OH-, decreases to the same extent the dark- and light-induced signal of the heme Fe(III)-OH- and the light-induced multiline signal of the Mn cluster. These results are discussed in terms of the light-induced formation of a bound OH' radical shared between the Cyt b-559 heme Fe and the Mn cluster as a first step of water oxidation.
Fiege
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R
Max-Volmer-Institut fur Biophysikalische und Physicalische Chemie, Technische Universitat Berlin, Germany.
Shuvalov
V A
VA
D016227:Benzoquinones / Q000494:pharmacology; D003573:Cytochrome b Group / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D007425:Intracellular Membranes / Q000737:chemistry; D008345:Manganese / Q000737:chemistry*; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D012969:Sodium Fluoride / Q000494:pharmacology
D016227:Benzoquinones; D003573:Cytochrome b Group; D006878:Hydroxides; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C000928:dichlorodicyanobenzoquinone; D006418:Heme; D008345:Manganese; D012969:Sodium Fluoride; C019313:cytochrome b559; C031356:hydroxide ion