Mechanistic Characterization of Escherichia coli l-Aspartate Oxidase from Kinetic Isotope Effects.

ABSTRACT: l-Aspartate oxidase, encoded by the nadB gene, is the first enzyme in the de novo synthesis of NAD⁺ in bacteria. This FAD-dependent enzyme catalyzes the oxidation of l-aspartate to generate iminoaspartate and reduced flavin. Distinct from most amino acid oxidases, it can use either molecular oxygen or fumarate to reoxidize the reduced enzyme. Sequence alignments and the three-dimensional crystal structure have revealed that the overall fold and catalytic residues of NadB closely resemble those of the succinate dehydrogenase/fumarate reductase family rather than those of the prototypical d-amino acid oxidases. This suggests that the enzyme can catalyze amino acid oxidation via typical amino acid oxidase chemistry, involving the removal of protons from the α-amino group and the tr

SUBMITTER: Chow C 

PROVIDER: S-EPMC5839506 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature