This is the C-terminal NAT or N-acetyltransferase domain of bifunctional N-acetylglutamate synthase/kinases. It catalyzes the first two steps in arginine biosynthesis. This domain contains the putative NAGS - N-acetylglutamate synthase - active site. It is found at the C-terminus of Neurospora crassa acetylglutamate synthase - amino-acid acetyltransferase, EC: 2.3.1.1. It is also found C-terminal to the amino acid kinase region (Pfam:PF00696) in some fungal acetylglutamate kinase enzymes [1]. it stabilises the yeast NAGK, N-acetyl-L-glutamate kinase, slows catalysis and modulates feed-back inhibition by arginine [2]. This domain is found to be the N-acetyltransferase (NAT) domain, and it has a typical GCN5-related NAT fold and a site that catalyzes NAG synthesis which is located >25 Angstrom away from the L-arginine binding site in the N-temrinal domain Pfam:PF00696 [3].

1: A novel N-acetylglutamate synthase architecture revealed by the crystal structure of the bifunctional enzyme from Maricaulis maris. Shi D, Li Y, Cabrera-Luque J, Jin Z, Yu X, Zhao G, Haskins N, Allewell NM, Tuchman M; PLoS One. 2011;6:e28825. PMID:22174908

2: Insight on an arginine synthesis metabolon from the tetrameric structure of yeast acetylglutamate kinase. de Cima S, Gil-Ortiz F, Crabeel M, Fita I, Rubio V; PLoS One. 2012;7:e34734. PMID:22529931

3: Crystal structure of the N-acetyltransferase domain of human N-acetyl-L-glutamate synthase in complex with N-acetyl-L-glutamate provides insights into its catalytic and regulatory mechanisms. Zhao G, Jin Z, Allewell NM, Tuchman M, Shi D; PLoS One. 2013;8:e70369. PMID:23894642