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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
Author(s) -
Fiege Rober,
Shuvalov Vladimir A.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00458-9
Subject(s) - electron paramagnetic resonance , heme , chemistry , cluster (spacecraft) , photochemistry , ion , membrane , crystallography , nuclear magnetic resonance , biochemistry , physics , computer science , programming language , enzyme , organic chemistry
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.