Bacterial ApbC can bind and effectively transfer iron-sulfur clusters

Biochemistry. 2008 Aug 5;47(31):8195-202. doi: 10.1021/bi800551y. Epub 2008 Jul 11.


The metabolism of iron-sulfur ([Fe-S]) clusters requires a complex set of machinery that is still being defined. Mutants of Salmonella enterica lacking apbC have nutritional and biochemical properties indicative of defects in [Fe-S] cluster metabolism. ApbC is a 40.8 kDa homodimeric ATPase and as purified contains little iron and no acid-labile sulfide. An [Fe-S] cluster was reconstituted on ApbC, generating a protein that bound 2 mol of Fe and 2 mol of S (2-) per ApbC monomer and had a UV-visible absorption spectrum similar to known [4Fe-4S] cluster proteins. Holo-ApbC could rapidly and effectively activate Saccharomyces cerevisiae apo-isopropylmalate isolomerase (Leu1) in vitro, a process known to require the transfer of a [4Fe-4S] cluster. Maximum activation was achieved with 2 mol of ApbC per 1 mol of apo-Leu1. This article describes the first biochemical activity of ApbC in the context of [Fe-S] cluster metabolism. The data herein support a model in which ApbC coordinates an [4Fe-4S] cluster across its dimer interface and can transfer this cluster to an apoprotein acting as an [Fe-S] cluster scaffold protein, a function recently deduced for its eukaryotic homologues.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • GTP-Binding Proteins / chemistry
  • GTP-Binding Proteins / metabolism
  • Iron / chemistry
  • Iron / metabolism*
  • Isomerases / metabolism
  • Models, Biological
  • Molecular Sequence Data
  • Mutation
  • Protein Binding
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Sulfur / chemistry
  • Sulfur / metabolism*


  • ApbC protein, Salmonella typhimurium
  • Bacterial Proteins
  • Cfd1 protein, S cerevisiae
  • NBP35 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Sulfur
  • Iron
  • Adenosine Triphosphatases
  • GTP-Binding Proteins
  • isopropylmalate isomerase
  • Isomerases