InterPro domain: IPR001041

Ferredoxins are small, acidic, electron transfer proteins that are ubiquitousin biological redox systems. They have either 4Fe-4S, 3Fe-4S, or 2Fe-2Scluster. Among them, ferredoxin with one 2Fe-2S cluster per molecule arepresent in plants, animals, and bacteria, and form a distinct Ferredoxinfamily [ 1 ]. They are proteins of around one hundred amino acids with four conserved cysteine residues to which the 2Fe-2S cluster is ligated. This conserved region is also found as a domain in various metabolic enzymes.

Several structures of the 2Fe-2S ferredoxin-type domain have been determined [ 2 ]. The domain is classified as a beta-grasp, which is characterised as having a beta-sheet comprised of four beta-strands and one alpha-helix flanking the sheet. The two Fe atoms are coordinated tetrahedrally by the two inorganic S atoms and four cysteinyl S atoms.

1. Divergent evolution of chloroplast-type ferredoxins. FEBS Lett. 285, 85-8
2. Tertiary structure of [2Fe-2S] ferredoxin from Spirulina platensis refined at 2.5 A resolution: structural comparisons of plant-type ferredoxins and an electrostatic potential analysis. J. Biochem. 117, 1017-23