Non‐inhibiting perturbation of the primary energy conversion site (Qo site) in Rhodobacter capsulatus ubihydroquinone:cytochrome c oxidoreductase (cytochrome bc 1 complex)

FEBS Letters

Gibney, Brian R¹  Moser, Christopher C¹  Palmitessa, Aimee¹  Sharp, R.Eryl¹  Daldal, Fevzi²  Dutton, P.Leslie¹ 

[1] Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA;Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA

关键词: Cytochrome bc 1 complex;    [2Fe-2S] cluster;    Qo site;    Alcohol;    Ubiquinone;   

DOI  :  10.1016/S0014-5793(98)00792-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ethanol added to Rhodobacter capsulatus chromatophore membranes containing the cytochrome bc ₁ complex effectively uncouples the sensitivity of the [2Fe-2S] cluster EPR spectrum to the number and redox state of ubiquinone/ubihydroquinone within the Q_o site. Ethanol has no effect upon the rate of catalysis, leading to a non-inhibiting perturbation of cytochrome bc ₁ function. We suggest that displacement occurs by ethanol acting from the aqueous phase to successfully compete with the Q_o site ubiquinones and water to hydrogen bond the N_ϵH atom(s) of the coordinating [2Fe-2S] cluster histidines.

【 授权许可】

Unknown