Protonmotive pathways and mechanisms in the cytochrome bc 1 complex

FEBS Letters

Hunte, Carola²  Palsdottir, Hildur²  Trumpower, Bernard L¹ 

[1] Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA;Department Molecular Membrane Biology, Max-Planck-Institute Biophysics, D-60439 Frankfurt am Main, Germany

关键词: bc 1 complex;    Protonmotive;    Q cycle;    Crystal structure;    Cytochrome c reductase;    Cytochrome b;    UQ6;    ubiquinone-6;    UHDBT;    3-undecyl-2-hydroxy-1;    4-dioxobenzoxythiazol;    HHDBT;    3-heptyl-2-hydroxy-1;    4-dioxobenzoxythiazol;    CL;    cardiolipin;   

DOI  :  10.1016/S0014-5793(03)00391-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The cytochrome bc ₁ complex catalyzes electron transfer from ubiquinol to cytochrome c by a protonmotive Q cycle mechanism in which electron transfer is linked to proton translocation across the inner mitochondrial membrane. In the Q cycle mechanism proton translocation is the net result of topographically segregated reduction of quinone and reoxidation of quinol on opposite sides of the membrane, with protons being carried across the membrane as hydrogens on the quinol. The linkage of proton chemistry to electron transfer during quinol oxidation and quinone reduction requires pathways for moving protons to and from the aqueous phase and the hydrophobic environment in which the quinol and quinone redox reactions occur. Crystal structures of the mitochondrial cytochrome bc ₁ complexes in various conformations allow insight into possible proton conduction pathways. In this review we discuss pathways for proton conduction linked to ubiquinone redox reactions with particular reference to recently determined structures of the yeast bc ₁ complex.

【 授权许可】

Unknown