Structural analysis of cytochrome bc1 complexes: implications to the mechanism of function

Biochim Biophys Acta. Nov-Dec 2013;1827(11-12):1278-94. doi: 10.1016/j.bbabio.2012.11.008. Epub 2012 Nov 29.


The cytochrome bc1 complex (bc1) is the mid-segment of the cellular respiratory chain of mitochondria and many aerobic prokaryotic organisms; it is also part of the photosynthetic apparatus of non-oxygenic purple bacteria. The bc1 complex catalyzes the reaction of transferring electrons from the low potential substrate ubiquinol to high potential cytochrome c. Concomitantly, bc1 translocates protons across the membrane, contributing to the proton-motive force essential for a variety of cellular activities such as ATP synthesis. Structural investigations of bc1 have been exceedingly successful, yielding atomic resolution structures of bc1 from various organisms and trapped in different reaction intermediates. These structures have confirmed and unified results of decades of experiments and have contributed to our understanding of the mechanism of bc1 functions as well as its inactivation by respiratory inhibitors. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.

Keywords: Bifurcated electron flow; Bos taurus bc(1); Btbc(1); CA; CL; Control of ISP domain movement; Crystal structure; Cytochrome bc(1) complex; ET; Gallus gallus bc(1); Ggbc(1); ISC; ISP; ISP-ED; MPP; Mechanism of ubiquinol oxidation; Mtbc(1); NCS; Non-crystallographic symmetry; PC; PDB; PE; PI; Q; Q(N); Q(P); QH(2); SC; Scbc(1); TM; b(H); b(L); bc(1); bc(1) from Saccharomyces cerevisiae; cardiolipin; complex III or ubiquinol cytochrome c oxidoreductase or cytochrome bc(1); contact area; electron transfer; extrinsic domain of ISP; from Rhodobacter sphaeroides; high-potential heme or b(562); iron–sulfur cluster; iron–sulfur protein; low-potential heme or b(566); mitochondrial bc(1); mitochondrial processing peptidase; phosphatidylcholine; phosphatidylethanolamine; phosphatidylinositol; protein data bank; rms deviation; root-mean-square deviation; surface complementarity; transmembrane; ubiquinol; ubiquinol oxidation,Rsbc(1); ubiquinone; ubiquinone reduction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Review

MeSH terms

  • Electron Transport
  • Electron Transport Complex III / chemistry*
  • Electron Transport Complex III / metabolism
  • Metals / chemistry
  • Metals / metabolism
  • Models, Molecular
  • Phospholipids / chemistry
  • Phospholipids / metabolism
  • Protein Binding
  • Protein Conformation*
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • Substrate Specificity


  • Metals
  • Phospholipids
  • Protein Subunits
  • Electron Transport Complex III