Mutational analysis of the Qi-site proton pathway in yeast cytochrome bc1 complex.
Biochem Biophys Res Commun
; 523(3): 615-619, 2020 03 12.
Article
en En
| MEDLINE
| ID: mdl-31941609
The respiratory cytochrome bc1 complex functions as a protonmotive ubiquinol:cytochrome c oxidoreductase. Lysine 228 (K228) located within the quinol reduction (Qi) site of the bc1 complex, has been reported as a key residue for proton transfer during the redox chemistry cycle to substrate quinone at Qi. In yeast, while single mutations had no effect, the combination of K228L and F225L resulted in a severe respiratory growth defect and inhibition of O2 consumption in intact cells. The inhibition was overcome by uncoupling the mitochondrial membrane or by suppressor mutations in the region of K228L-F225L. We propose that the K228L mutation introduces energetic (and kinetic) barriers into normal electron- and proton transfer chemistry at Qi, which are relieved by dissipation of the opposing protonmotive force or through the restoration of favourable intraprotein proton transfer networks via suppressor mutation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
/
Citocromos c1
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Proteínas de Saccharomyces cerevisiae
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Citocromos b
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
2020
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
Estados Unidos