<p>These sequences represent the gamma chain of the gamma proteobacteria (and <taxon tax_id="63363">Aquifex aeolicus</taxon>) formate dehydrogenase. This subunit is integral to the cytoplasmic membrane, consisting of 4 transmembrane helices, and receives electrons from the beta subunit. The entire <taxon tax_id="562">Escherichia coli</taxon> formate dehydrogenase N (nitrate-inducible form) has been crystallized and its structure determined [<cite idref="PUB00009871"/>]. The gamma subunit contains two cytochromes, haem b(P) and haem b(C) near the periplasmic and cytoplasmic sides of the membrane respectively. The electron acceptor quinone binds at the cytoplasmic haem histidine ligand. NiFe-hydrogenase and thiosulphate reductase contain homologous gamma subunits, and these are found in this group.</p> Formate dehydrogenase, gamma subunit