InterPro domain: IPR011053

The single hybrid motif has a beta-barrel sandwich hybrid fold, consisting of a sandwich of half-barrel shaped beta-sheets. This motif is found in biotinyl/lipoyl-carrier proteins and domains, where the biotin and lipoic acid moieties act as covalently attached coenzyme cofactors in enzymes that catalyse metabolic reactions. For example, this motif can be found in the biotinyl domain of Escherichia coli acetyl-CoA carboxylase [ 1 ], protein H of the glycine cleavage system in Pisum sativum (Garden pea) [ 2 ], the ipoyl domain of dihydrolipoamide acetyltransferase, which is a component of the pyruvate dehydrogenase complex [ 3 ], the lipoyl domain of the 2-oxoglutarate dehydrogenase complex [ 4 ], and the lipoyl domain f the mitochondrial branched-chain alpha-ketoacid dehydrogenase.

1. Structure of the biotinyl domain of acetyl-coenzyme A carboxylase determined by MAD phasing. Structure 3, 1407-19
2. Interaction between the lipoamide-containing H-protein and the lipoamide dehydrogenase (L-protein) of the glycine decarboxylase multienzyme system 2. Crystal structures of H- and L-proteins. Eur. J. Biochem. 267, 2890-8
3. Restricted motion of the lipoyl-lysine swinging arm in the pyruvate dehydrogenase complex of Escherichia coli. Biochemistry 39, 8448-59
4. Three-dimensional structure of the lipoyl domain from the dihydrolipoyl succinyltransferase component of the 2-oxoglutarate dehydrogenase multienzyme complex of Escherichia coli. J. Mol. Biol. 264, 179-90