Allows to use formate as major electron donor during aerobic respiration. The beta chain is an electron transfer unit containing 4 cysteine clusters involved in the formation of iron-sulfur centers. Electrons are transferred from the gamma chain to the molybdenum cofactor of the alpha subunit (By similarity). Binds 4 [4Fe-4S] clusters per subunit. Formate dehydrogenase is a membrane-bound complex, formed by subunits alpha, beta and gamma.