<p>The sequences in this group represent the beta subunit of the gamma-proteobacterial formate dehydrogenase. This subunit contains four 4Fe-4S clusters and is involved in transmitting electrons from the alpha subunit (<db_xref db="INTERPRO" dbkey="IPR006443"/>) at the periplasmic space to the gamma subunit which spans the cytoplasmic membrane [<cite idref="PUB00009871"/>]. In addition to the gamma proteobacteria, a sequence from Aquifex aolicus falls within this group. This appears to be the case for the alpha, gamma and epsilon (accessory protein <db_xref db="INTERPRO" dbkey="IPR006452"/>) chains as well. </p> Formate dehydrogenase, beta subunit