Crystal structure of bovine mitochondrial factor B at 0.96-A resolution

Proc Natl Acad Sci U S A. 2008 Sep 9;105(36):13379-84. doi: 10.1073/pnas.0805689105. Epub 2008 Sep 3.


Coupling factor B (FB) is a mitochondrial inner membrane polypeptide that facilitates the energy-driven catalysis of ATP synthesis in animal mitochondria by blocking a proton leak across the membrane. Here, we report the crystal structure of the bovine mitochondrial FB mutant with Gly-3-Glu substitution determined at a resolution of 0.96 A and that of the WT polypeptide at a resolution of 2.9 A. The structure reveals an oblong, oval-shaped molecule with a unique globular N-terminal domain that is proposed to be the membrane anchor domain and the capping region to the C-terminal leucine-rich repeats domain. A short N-terminal alpha-helix, which extends away from the molecule's body, is suggestive of functioning as an anchor for FB to the matrix side of the mitochondrial inner membrane. Identification of a bound Mg(2+) ion reveals that FB is a metalloprotein. We also report the cocrystal structures of FB bound with phenylarsine oxide and Cd(2+), two known inhibitors of the FB coupling activity.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • Cadmium / chemistry
  • Cadmium / metabolism
  • Cattle
  • Crystallography, X-Ray
  • Mitochondrial Proton-Translocating ATPases / chemistry*
  • Mitochondrial Proton-Translocating ATPases / genetics
  • Mitochondrial Proton-Translocating ATPases / metabolism
  • Models, Molecular
  • Mutation / genetics
  • Oxidative Phosphorylation Coupling Factors / chemistry*
  • Oxidative Phosphorylation Coupling Factors / genetics
  • Oxidative Phosphorylation Coupling Factors / metabolism
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary


  • Oxidative Phosphorylation Coupling Factors
  • Cadmium
  • coupling factor B
  • Mitochondrial Proton-Translocating ATPases

Associated data

  • PDB/3DZE
  • PDB/3E2J
  • PDB/3E3Z
  • PDB/3E4G