InterPro domain: IPR024083

This entry represents an N-terminal structural domain which forms an alpha-helical orthogonal bundle found in fumarate lyase (fumarase) and related proteins, as well as in histidine ammonia-lyase (or histidase) [ 1 ].

One member of the fumarate lyase family is L-aspartate ammonia-lyase (aspartase), which catalyses the reversible deamination of the amino acid L-aspartic acid, using a carbanion mechanism to produce fumaric acid and ammonium ion. Aspartases from different organisms show high sequence homology, and this homology extends to functionally related enzymes such as the class II fumarases, the argininosuccinate and adenylosuccinate lyases. The high-resolution structure of aspartase reveals a monomer that is composed of three domains oriented in an elongated S-shape [ 2 ].

1. Crystal structure of histidine ammonia-lyase revealing a novel polypeptide modification as the catalytic electrophile. Biochemistry 38, 5355-61
2. The structure of L-aspartate ammonia-lyase from Escherichia coli. Biochemistry 36, 9136-44