Systematic Functional Analysis of Active-Site Residues in l-Threonine Dehydrogenase from Thermoplasma volcanium.

ABSTRACT: Enzymes have been through millions of years of evolution during which their active-site microenvironments are fine-tuned. Active-site residues are commonly conserved within protein families, indicating their importance for substrate recognition and catalysis. In this work, we systematically mutated active-site residues of l-threonine dehydrogenase from Thermoplasma volcanium and characterized the mutants against a panel of substrate analogs. Our results demonstrate that only a subset of these residues plays an essential role in substrate recognition and catalysis and that the native enzyme activity can be further enhanced roughly 4.6-fold by a single point mutation. Kinetic characterization of mutants on substrate analogs shows that l-threonine dehydrogenase possesses promiscuous ac

SUBMITTER: Desjardins M 

PROVIDER: S-EPMC6641618 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature