Bifurcated ubihydroquinone oxidation in the cytochrome bc1 complex by proton‐gated charge transfer
- 27 May 1996
- journal article
- review article
- Published by Wiley in FEBS Letters
- Vol. 387 (1) , 1-6
- https://doi.org/10.1016/0014-5793(96)00436-x
Abstract
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.Keywords
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