Abstract 1911 Role of Arg108 in the binding of NADH by 6-hydroxynicotinate 3-monooxygenase (NicC)

Nicotinic acid (NA), a carboxylic derivative of pyridine, represents a model substrate in microbial degradation pathways of N-heterocyclic aromatic compounds, environmental pollutants with carcinogenic and toxic properties. 6-Hydroxynicotinate 3-monooxygenase (NicC) catalyzes the conversion of 6-hydroxynicotinate (6-HNA) to 2,5-dihydroxypyridine (2,5-DHP), a pivotal step in NA degradation requiring NADH-mediated reduction of NicC's FAD coenzyme. Despite the critical role of NADH in NicC's enzymatic mechanism, the amino acid determinants of its binding remain uncharacterized.