Localization of acidic residues involved in the proton pumping activity of the bovine heart mitochondrial bc1 complex

FEBS Letters

Lorusso, Michele¹  Di Paola, Marco¹  Cocco, Tiziana¹  Papa, Sergio¹ 

[1] Institute of Medical Biochemistry and Chemistry, University of Bari, Bari, Italy

关键词: Mitochondria;    bc1 complex;    Proton transport;    Carboxyl residue;    Chemical modification;    Decoupling;    DCCD;    N;    N′-dicyclohexylcarbodiimide;    EEDQ;    N-(ethoxycarbonyl)-2-ethoxy-1;    2-dihydroquinoline;    AMF;    4′-((aminoacetamido)methyl)fluorescein;    ISP;    iron-sulfur protein;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;    ΔpH;    transmembrane pH gradient;   

DOI  :  10.1016/S0014-5793(99)00920-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Chemical modification of carboxyl residues in polypeptide subunits of the mitochondrial bc₁ complex causes a decoupling effect, that is inhibition of the proton pumping activity, without affecting the rate of electron transfer to ferricytochrome c. The study presented here is aimed at localizing and identifying the residues whose modification results in decoupling of the complex. Glutamate-53 in subunit IX (the DCCD-binding protein) and aspartate-166 in the Rieske iron-sulfur protein are the residues modified by N,N′-dicyclohexylcarbodiimide (DCCD) and N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline (EEDQ), respectively. The results obtained also suggest that the carboxy-terminal sequence of the Core protein II, which is fairly rich in acidic residues, may also play a role in the vectorial proton translocation activity of the complex.

【 授权许可】

Unknown