Citrobacter freundii Methionine γ-Lyase: The Role of Serine 339 in the Catalysis of γ- and β-Elimination Reactions.

ABSTRACT: Serine 339 of the active site of Citrobacter freundii methionine γ-lyase (MGL) is a conserved amino acid in most pyridoxal 5'-phosphate-dependent enzymes of the cystathionine β-lyase subclass, to which MGL belongs. The reaction mechanism of the MGL-catalyzed γ-elimination reaction is poorly explored. We replaced serine 339 with alanine using site-directed mutagenesis. The replacement of serine 339 with alanine led to a significant (by two orders of magnitude) decrease in efficiency in the catalysis of the γ- and β-elimination reactions by the mutant form of the enzyme. The exchange rates of the C-α- and C-β-protons in the amino acids in complexes consisting of the enzyme and competitive inhibitors decreased by one-two orders of magnitude. The spectral characteristics of the mutant f

SUBMITTER: Anufrieva NV 

PROVIDER: S-EPMC9307983 | biostudies-literature | 2022 Apr-Jun

REPOSITORIES: biostudies-literature