InterPro domain: IPR002813

ArgJ (also known as Ornithine acetyltransferase/OAT) is a bifunctional protein that catalyses the first 2.3.1.35 and fifth steps 2.3.1.1 in arginine biosynthesis [ 1 ], coupling acetylation of glutamate with deacetylation of N-acetylornithine, which allows recycling of the acetyl group in the arginine biosynthetic pathway. The structure has been determined for glutamate N-acetyltransferase 2 (ornithine acetyltransferase; 2.3.1.35 ), an ArgJ-like protein from Streptomyces clavuligerus [ 2 ].

Members of this family may experience feedback inhibition by L-arginine. The active enzyme is a heterotetramer of two alpha and two beta chains, where the alpha and beta chains are the result of autocatalytic cleavage. OATs found in the clavulanic acid biosynthesis gene cluster catalyze the fifth step only, and may utilize acetyl acceptors other than glutamate [ 3 , 4 , 4 , 5 , 5 , 6 ].

1. Primary structure, partial purification and regulation of key enzymes of the acetyl cycle of arginine biosynthesis in Bacillus stearothermophilus: dual function of ornithine acetyltransferase. J. Gen. Microbiol. 139, 393-402
2. X-ray crystal structure of ornithine acetyltransferase from the clavulanic acid biosynthesis gene cluster. Biochem. J. 385, 565-73
3. Two proteins with ornithine acetyltransferase activity show different functions in Streptomyces clavuligerus: Oat2 modulates clavulanic acid biosynthesis in response to arginine. J. Bacteriol. 186, 6501-7
4. N-acetylglutamate and its changing role through evolution. Biochem. J. 372, 279-90
5. Enzymes of arginine biosynthesis and their repressive control. Adv. Enzymol. Relat. Areas Mol. Biol. 40, 65-90
6. DOM-fold: a structure with crossing loops found in DmpA, ornithine acetyltransferase, and molybdenum cofactor-binding domain. Protein Sci. 14, 1902-10