Structural Basis for the Catalytic Mechanism of ATP-Dependent Diazotase CmaA6.

ABSTRACT: Although several diazotases have been recently reported, the details of the reaction mechanism are not yet understood. In this study, we investigated the mechanism of CmaA6, an ATP-dependent diazotase, which catalyzes the diazotization of 3-aminocoumaric acid using nitrous acid. X-ray crystallography and cryogenic electron microscopy-single particle analysis revealed CmaA6 structures in the substrate-free and AMP-binding states. Kinetic analysis suggested that CmaA6 catalyzes diazotization via a sequential reaction mechanism in which three substrates (nitrous acid, ATP, and 3-aminocoumaric acid) are simultaneously bound in the reaction pocket. The nitrous acid and 3-aminocoumaric acid binding sites were predicted based on the AMP-binding state and confirmed by site-directed mutagenesis. In

SUBMITTER: Kawai S 

PROVIDER: S-EPMC12207350 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature