Evidence for a mobile semiquinone in the redox cycle of the mammalian cytochrome bc 1 complex

FEBS Letters

Rich, Peter R.¹  Wikström, Mårten² 

[1] Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 IQW, England;Department of Medical Chemistry, University of Helsinki, Siltavuorenpenger 10A, SF-00170 Helsinki, Finland

关键词: Cytochrome b Ubisemiquinone Electron transfer Energy conservation Q cycle Cytochrome b cycle;   

DOI  :  10.1016/0014-5793(86)80072-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Experimental evidence is presented to demonstrate that cytochromes b of the mammalian cytochrome bc ₁ complex may be rapidly oxidised by a pulse of oxidising equivalents which react with cytochrome c ₁ even when all cytochrome b is fully reduced before the pulse. The oxidation is sensitive both to antimycin and to myxothiazol. Such behaviour is inconsistent with models in which only the fully oxidised ubiquinone may move beween the centres ‘o’ and ‘i’ of the complex. It is proposed that the charged semiquinone (Q⁻) may move between these centres, which may constitute separate reaction domains of a single ubiquinone-binding site. The bearing of this on the mechanism of electron, proton and charge transfer in the complex is discussed.

【 授权许可】

Unknown