<p>Proteins containing this domain form structural complexes with other known families, such as <db_xref db="INTERPRO" dbkey="IPR008274"/> and <db_xref db="INTERPRO" dbkey="IPR001041"/>]. The carbon monoxide (CO) dehydrogenase of <taxon tax_id="40137">Oligotropha carboxidovorans</taxon> is a heterotrimeric complex composed of a apoflavoprotein, a molybdoprotein, and an iron-sulphur protein. It can be dissociated with sodium dodecylsulphate [<cite idref="PUB00043387"/>]. CO dehydrogenase catalyzes the oxidation of CO according to the following equation [<cite idref="PUB00015703"/>]: <reaction> CO + H2O = CO2 + 2e + 2H+ </reaction> </p> <p>Subunit S represents the iron-sulphur protein of CO dehydrogenase and is clearly divided into a C- and an N-terminal domain, each binding a [2Fe-2S] cluster [<cite idref="PUB00019122"/>].</p>