InterPro domain: IPR009288

This entry represents a domain found in a group of gamma-glutamyl cyclotransferases (GGCTs), including AIG2 from Arabidopsis. GGCT is a ubiquitous enzyme found in bacteria, plants, and metazoans from Dictyostelium through to humans. It converts gamma-glutamylamines to free amines and 5-oxoproline [ 1 , 2 , 3 ].

AIG2 is an Arabidopsis protein that exhibit RPS2- and avrRpt2-dependent induction early after infection with Pseudomonas syringae pv maculicola strain ES4326 carrying avrRpt2 [ 4 ]. Its structure consists of a five-stranded beta-barrel surrounded by two alpha-helices and a small beta-sheet. A long flexible alpha-helix protrudes from the structure at the C-terminal end. Conserved residues in a hydrophilic cavity, which are able to bind small ligands, may act as an active site in AIG2-like proteins [ 5 ].

1. Identification and characterization of gamma-glutamylamine cyclotransferase, an enzyme responsible for gamma-glutamyl-epsilon-lysine catabolism. J. Biol. Chem. 285, 9642-8
2. Structural and biochemical studies elucidate the mechanism of rhamnogalacturonan lyase from Aspergillus aculeatus. J. Mol. Biol. 404, 100-11
3. Biosynthesis of butirosin: transfer and deprotection of the unique amino acid side chain. Chem. Biol. 14, 379-86
4. Isolation of Arabidopsis genes that differentiate between resistance responses mediated by the RPS2 and RPM1 disease resistance genes. Plant Cell 8, 241-9
5. Solution structure of Arabidopsis thaliana protein At5g39720.1, a member of the AIG2-like protein family. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 62, 490-3