MacA, a diheme c-type cytochrome involved in Fe(III) reduction by Geobacter sulfurreducens

J Bacteriol. 2004 Jun;186(12):4042-5. doi: 10.1128/JB.186.12.4042-4045.2004.


A 36-kDa diheme c-type cytochrome abundant in Fe(III)-respiring Geobacter sulfurreducens, designated MacA, was more highly expressed during growth with Fe(III) as the electron acceptor than with fumarate. Although MacA has homology to proteins with in vitro peroxidase activity, deletion of macA had no impact on response to oxidative stress. However, the capacity for Fe(III) reduction was greatly diminished, indicating that MacA, which is predicted to be localized in the periplasm, is a key intermediate in electron transfer to Fe(III).

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cytochrome c Group / genetics
  • Cytochrome c Group / metabolism*
  • Deltaproteobacteria / enzymology*
  • Deltaproteobacteria / growth & development
  • Electron Transport
  • Ferric Compounds / metabolism*
  • Gene Deletion
  • Molecular Sequence Data
  • Oxidation-Reduction


  • Bacterial Proteins
  • Cytochrome c Group
  • Ferric Compounds