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Suppression of superoxide production by a spin‐spin coupling between semiquinone and the Rieske cluster in cytochrome bc 1
Author(s) -
Bujnowicz Łukasz,
Borek Arkadiusz,
Kuleta Patryk,
Sarewicz Marcin,
Osyczka Artur
Publication year - 2019
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 - 10.1002/1873-3468.13296
Subject(s) - superoxide , semiquinone , chemistry , cytochrome c , cytochrome , photochemistry , enzyme , stereochemistry , biochemistry , mitochondrion , quinone
Catalytic reactions of quinol oxidoreductases may lead to the generation of superoxide due to electron leaks from unstable semiquinone intermediates ( SQ ). For cytochrome bc 1 , the mechanism of suppression of superoxide generation remains unknown. We analyzed conditions of formation of a spin‐spin–coupled state between SQ and the Rieske cluster ( SQ ‐FeS) associated with catalysis of the quinol oxidation site of cytochrome bc 1 . We reveal that mutants that preclude direct interaction between SQ and the Rieske cluster do not form SQ ‐FeS and release enhanced superoxide. In the enzymes generating SQ ‐FeS, little or no superoxide is detected. We propose that SQ ‐FeS suppresses superoxide generation, becoming an element modulating superoxide release under physiologically relevant conditions slowing electron flow through the enzyme.