Structure and Function of Cytochrome Bc Complexes

Annu Rev Biochem. 2000;69:1005-75. doi: 10.1146/annurev.biochem.69.1.1005.


The cytochrome bc complexes represent a phylogenetically diverse group of complexes of electron-transferring membrane proteins, most familiarly represented by the mitochondrial and bacterial bc1 complexes and the chloroplast and cyanobacterial b6f complex. All these complexes couple electron transfer to proton translocation across a closed lipid bilayer membrane, conserving the free energy released by the oxidation-reduction process in the form of an electrochemical proton gradient across the membrane. Recent exciting developments include the application of site-directed mutagenesis to define the role of conserved residues, and the emergence over the past five years of X-ray structures for several mitochondrial complexes, and for two important domains of the b6f complex.

Publication types

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

MeSH terms

  • Animals
  • Chloroplasts / chemistry
  • Crystallography, X-Ray
  • Cyanobacteria / chemistry
  • Electron Transport
  • Electron Transport Complex III / chemistry*
  • Electron Transport Complex III / genetics
  • Electron Transport Complex III / metabolism*
  • Hydroquinones / metabolism
  • Models, Molecular
  • Oxidation-Reduction
  • Phylogeny
  • Protein Subunits


  • Hydroquinones
  • Protein Subunits
  • Electron Transport Complex III