Members of this largely archaeal protein family are subunit B of the formylmethanofuran dehydrogenase. Nomenclature in some bacteria may reflect inclusion of the formyltransferase described by TIGR03119 as part of the complex, and therefore call this protein formyltransferase/hydrolase complex Fhc subunit C. Note that this model does not distinguish tungsten (FwdB) from molybdenum-containing (FmdB) forms of this enzyme.