Medicine and Health Sciences Commons^™

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, Gengxiang Zhao, Zhongmin Jin, Norma M. Allewell, Mendel Tuchman, Dashuang Shi

Pediatrics Faculty Publications

N-acetylglutamate synthase (NAGS) catalyzes the conversion of AcCoA and L-glutamate to CoA and N-acetyl-L-glutamate (NAG), an obligate cofactor for carbamyl phosphate synthetase I (CPSI) in the urea cycle. NAGS deficiency results in elevated levels of plasma ammonia which is neurotoxic. We report herein the first crystal structure of human NAGS, that of the catalyticN-acetyltransferase (hNAT) domain with N-acetyl-L-glutamate bound at 2.1 Å resolution. Functional studies indicate that the hNAT domain retains catalytic activity in the absence of the amino acid kinase (AAK) domain. Instead, the major functions of the AAK domain appear to be providing …