Isolation and mechanism analysis of a catalytic efficiency improved L-aspartate β-decarboxylase toward 3-methylaspartic acid

L-Aspartate β-decarboxylase from Acinetobacter radioresistens (ArASD) has been modified to convert 3-methylaspartic acid into 2-aminobutyric acid, which activated a novel process for biosynthesis of acid. However, the is limited by low activity ArASD. Here, ArASD was significantly improved modification based on sequence alignment and structural analysis. The 38th residue speculated be key regulating conformation internal aldimine, site-directed mutagenesis R38 carried out. A variant, K18A/R38K/V287I, with 2.2 times higher specific isolated. Molecular dynamics simulation indicated that torsion angle imine bond variant decreased, beneficial protonation aldimine increase in initial energy enzyme. Therefore, barrier transition state reduced, resulting catalytic toward These results provide reference new point view enzyme increasing state.