The alternative complex III: a different architecture using known building modules

Biochim Biophys Acta. 2010 Dec;1797(12):1869-76. doi: 10.1016/j.bbabio.2010.04.012. Epub 2010 Apr 21.


Until recently cytochrome bc(1) complexes were the only enzymes known to be able to transfer electrons from reduced quinones to cytochrome c. However, a complex with the same activity and with a unique subunit composition was purified from the membranes of Rhodothermus marinus. This complex, named alternative complex III (ACIII) was then biochemical, spectroscopic and genetically characterized. Later it was observed that the presence of ACIII was not exclusive of R. marinus being the genes coding for ACIII widespread, at least in the Bacteria domain. In this work, a comprehensive description of the current knowledge on ACIII is presented. The relation of ACIII with members of the complex iron-sulfur molybdoenzyme family is investigated by analyzing all the available completely sequenced genomes. It is concluded that ACIII is a new complex composed by a novel combination of modules already identified in other respiratory complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Cell Membrane / metabolism
  • Electron Transport
  • Electron Transport Complex III / classification
  • Electron Transport Complex III / genetics*
  • Electron Transport Complex III / metabolism
  • Gene Order
  • Multigene Family*
  • Phylogeny
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Rhodothermus / enzymology*


  • Bacterial Proteins
  • Protein Subunits
  • Electron Transport Complex III