Catalytic properties and crystal structure of UDP-galactose 4-epimerase-like l-threonine 3-dehydrogenase from Phytophthora infestans

Enzyme Microb Technol. 2020 Oct:140:109627. doi: 10.1016/j.enzmictec.2020.109627. Epub 2020 Jun 24.


We report, for the first time, the three-dimensional structure and biochemical properties of a UDP-galactose 4-epimerase-like l-threonine 3-dehydrogenase (GalE-like L-ThrDH) from Phytophthora infestans, a plant disease-causing fungus. We identified GalE-like L-ThrDH using Kyoto Encyclopedia of Genes and Genomes (KEGG) database as a candidate target for the development of a new fungicide. The GalE-like L-ThrDH gene was expressed in Escherichia coli, and its product was purified and characterized. N-Acetylglycine was found to act as a competitive inhibitor of the enzyme (Ki =0.18 mM). The crystal structure of the unique hexameric GalE-like L-ThrDH was determined using the molecular replacement method at a resolution of 2.3 Å, in the presence of NAD+ and citrate, an analogue of the substrate. Based on the molecular docking simulation, N-acetylglycine molecule was modeled into the active site and the binding mode and inhibition mechanism of N-acetylglycine were elucidated.

Keywords: 3-dehydrogenase; Crystal structure; Enzymological characterization; Phytophthora infestans; UDP-galactose 4-epimerase-like l-threonine.

MeSH terms

  • Alcohol Oxidoreductases / antagonists & inhibitors
  • Alcohol Oxidoreductases / chemistry*
  • Alcohol Oxidoreductases / genetics
  • Alcohol Oxidoreductases / metabolism*
  • Binding Sites
  • Catalysis
  • Catalytic Domain
  • Crystallography, X-Ray
  • Enzyme Inhibitors / metabolism
  • Glycine / analogs & derivatives
  • Glycine / metabolism
  • Hydrogen-Ion Concentration
  • Models, Molecular
  • Molecular Docking Simulation
  • Phytophthora infestans / enzymology*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Temperature
  • Threonine / metabolism
  • UDPglucose 4-Epimerase / antagonists & inhibitors
  • UDPglucose 4-Epimerase / chemistry*
  • UDPglucose 4-Epimerase / genetics
  • UDPglucose 4-Epimerase / metabolism*


  • Enzyme Inhibitors
  • Recombinant Proteins
  • Threonine
  • Alcohol Oxidoreductases
  • L-threonine 3-dehydrogenase
  • UDPglucose 4-Epimerase
  • Glycine
  • aceturic acid