Iron-sulfur cluster assembly: characterization of IscA and evidence for a specific and functional complex with ferredoxin

J Biol Chem. 2001 Jun 22;276(25):22604-7. doi: 10.1074/jbc.M102902200. Epub 2001 Apr 23.


The synthesis of iron-sulfur clusters in Escherichia coli is believed to require a complex protein machinery encoded by the isc (iron-sulfur cluster) operon. The product of one member of this operon, IscA, has been overexpressed, purified, and characterized. It can assemble an air-sensitive [2Fe-2S] cluster as shown by UV-visible and resonance Raman spectroscopy. The metal form but not the apoform of IscA binds ferredoxin, another member of the isc operon, selectively, allowing transfer of iron and sulfide from IscA to ferredoxin and formation of the [2Fe-2S] holoferredoxin. These results thus suggest that IscA is involved in ferredoxin cluster assembly and activation. This is an important function because a functional ferredoxin is required for maturation of other cellular Fe-S proteins.

MeSH terms

  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • DNA Primers
  • Electrophoresis, Polyacrylamide Gel
  • Ferredoxins / metabolism*
  • Iron-Sulfur Proteins / metabolism*
  • Operon
  • Protein Binding
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism


  • Bacterial Proteins
  • DNA Primers
  • Ferredoxins
  • Iron-Sulfur Proteins
  • Recombinant Proteins