Deletion of subunit 9 of the Saccharomyces cerevisiae cytochrome bc1 complex specifically impairs electron transfer at the ubiquinol oxidase site (center P) in the bc1 complex

FEBS Lett. 1992 Nov 30;313(3):251-4. doi: 10.1016/0014-5793(92)81203-x.

Abstract

Deletion of QCR9, the nuclear gene encoding subunit 9 of the mitochondrial cytochrome bc1 complex in Saccharomyces cerevisiae, results in inactivation of the bc1 complex and inability of the yeast to grow on non-fermentable carbon sources. The loss of bc1 complex activity is due to loss of electron transfer activity at the ubiquinol oxidase site (center P) in the complex. Electron transfer at the ubiquinone reductase site (center N), is unaffected by the loss of subunit 9, but the extent of cytochrome b reduction is diminished. This is the first instance in which a supernumerary polypeptide, lacking a redox prosthetic group, has been shown to be required for an electron transfer reaction within the cytochrome bc1 complex.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cytochrome b Group / metabolism
  • Cytochromes c1 / metabolism
  • Electron Transport
  • Electron Transport Complex III / metabolism*
  • Intracellular Membranes / metabolism
  • Macromolecular Substances
  • Mitochondria / metabolism
  • Oxidation-Reduction
  • Saccharomyces cerevisiae
  • Structure-Activity Relationship
  • Ubiquinone / analogs & derivatives*
  • Ubiquinone / metabolism

Substances

  • Cytochrome b Group
  • Macromolecular Substances
  • Ubiquinone
  • Cytochromes c1
  • Electron Transport Complex III
  • ubiquinol