Directed evolution of the substrate specificity of dialkylglycine decarboxylase.

ABSTRACT: Dialkylglycine decarboxylase (DGD) is an unusual pyridoxal phosphate dependent enzyme that catalyzes decarboxylation in the first and transamination in the second half-reaction of its ping-pong catalytic cycle. Directed evolution was employed to alter the substrate specificity of DGD from 2-aminoisobutyrate (AIB) to 1-aminocyclohexane-1-carboxylate (AC6C). Four rounds of directed evolution led to the identification of several mutants, with clones in the final rounds containing five persistent mutations. The best clones show ~2.5-fold decrease in KM and ~2-fold increase in kcat, giving a modest ~5-fold increase in catalytic efficiency for AC6C. Additional rounds of directed evolution did not improve catalytic activity toward AC6C. Only one (S306F) of the five persistent mutations is close t

SUBMITTER: Taylor JL 

PROVIDER: S-EPMC4334570 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature