Superfamily includes proteins containing domains which bind to iron-sulfur clusters. Members include bacterial ferredoxins, various dehydrogenases, and various reductases. Structure of the domain is an alpha-antiparallel beta sandwich.
This family represents the small subunit of the Fe-only hydrogenases EC:1.18.99.1. The subunit is comprised of alternating random coil and alpha helical structures that encompasses the large subunit in a novel protein fold [1].