The crystal structure of the adenylation enzyme VinN reveals a unique ?-amino acid recognition mechanism.

ABSTRACT: Adenylation enzymes play important roles in the biosynthesis and degradation of primary and secondary metabolites. Mechanistic insights into the recognition of ?-amino acid substrates have been obtained for ?-amino acid adenylation enzymes. The Asp residue is invariant and is essential for the stabilization of the ?-amino group of the substrate. In contrast, the ?-amino acid recognition mechanism of adenylation enzymes is still unclear despite the importance of ?-amino acid activation for the biosynthesis of various natural products. Herein, we report the crystal structure of the stand-alone adenylation enzyme VinN, which specifically activates (2S,3S)-3-methylaspartate (3-MeAsp) in vicenistatin biosynthesis. VinN has an overall structure similar to that of other adenylation enzymes. The structure of the complex with 3-MeAsp revealed that a conserved Asp(230) residue is used in the recognition of the ?-amino group of 3-MeAsp similar to ?-amino acid adenylation enzymes. A mutational analysis and structural comparison with ?-amino acid adenylation enzymes showed that the substrate-binding pocket of VinN has a unique architecture to accommodate 3-MeAsp as a ?-amino acid substrate. Thus, the VinN structure allows the first visualization of the interaction of an adenylation enzyme with a ?-amino acid and provides new mechanistic insights into the selective recognition of ?-amino acids in this family of enzymes.

SUBMITTER: Miyanaga A 

PROVIDER: S-EPMC4223343 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature