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Bifurcated ubihydroquinone oxidation in the cytochrome bc 1 complex by proton‐gated charge transfer
Author(s) -
Brandt Ulrich
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)00436-x
Subject(s) - deprotonation , catalytic cycle , proton , electron transfer , chemistry , proton coupled electron transfer , chemical physics , photochemistry , electron transport chain , substrate (aquarium) , molecule , catalysis , computational chemistry , physics , ion , organic chemistry , quantum mechanics , biochemistry , oceanography , geology
The unique bifurcation of electron flow at the ubihydroquinone‐oxidation center of the cytochrome bc 1 complex is the energy‐conserving reaction of the protonmotive Q‐cycle and is prerequisite to vectorial proton translocation. The widely accepted Q‐cycle reaction scheme describes the overall electron and proton pathways, but does not address the detailed chemistry of this central step. Based on a model of the ubihydroquinone‐oxidation pocket containing two ubiquinone molecules in a stacked configuration, a detailed model for the reactions during steady‐state catalysis is proposed. In this proton‐gated charge‐transfer mechanism the reaction is controlled by the deprotonation of the substrate ubihydroquinone.