Bifurcated ubihydroquinone oxidation in the cytochrome bc 1 complex by proton‐gated charge transfer

FEBS Letters

Brandt, Ulrich¹ 

[1] Universitätsklinikum Frankfurt, Zentrum der Biologischen Chemie, Theodor-Stern-Kai 7, Haus 25B, D-60590 Frankfurt am Main, Germany

关键词: Cytochrome bc 1 complex;    Ubiquinone;    Q-cycle;    Charge-transfer mechanism;    Deprotonation;   

DOI  :  10.1016/0014-5793(96)00436-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown