<p>This entry consists of ferredoxins which are encoded in the nitrogen fixation regions of many nitrogen-fixing bacteria. The charcterised protein from <taxon tax_id="1061">Rhodobacter capsulatus</taxon> (Rhodopseudomonas capsulata) is homodimeric and contains two [4Fe-4S] clusters bound per monomer. Although nif-specific, these prtoeins are not universal in nitrogen-fixers as other nitrogenase systems may substitute flavodoxins, or different types of ferredoxin.</p> Ferredoxin III 4[4Fe-4S], nif-specific