This domain family is found in bacteria, and is approximately 40 amino acids in length. The family is found in association with Pfam:PF00676. There are two conserved sequence motifs: VPEP and RPG. This family is the alpha subunit of the E1 component of 2-oxoisovalerate dehydrogenase. This is the enzyme complex responsible for metabolism of pyruvate, 2-oxoglutarate, branched chain 2-oxo acids and acetoin. The E1 component is a heterotetramer of alpha2beta2. The homodimerised beta subunits are flanked by two alpha subunits in a 'vise' structure.

1: Crystal structure of 2-oxoisovalerate and dehydrogenase and the architecture of 2-oxo acid dehydrogenase multienzyme complexes. Aevarsson A, Seger K, Turley S, Sokatch JR, Hol WG; Nat Struct Biol. 1999;6:785-792. PMID:10426958