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

July 30, 2020

Title

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

Author

Kazunari Yoneda, Rina Nagano, Takuya Mikami, Haruhiko Sakuraba, Kenji Fukui, Tomohiro Araki, Toshihisa Ohshima

Year

2020

Journal

Enzyme and Microbial Technology

Abstract

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.

Instrument

J-820

Keywords

Circular dichroism, Secondary structure, Biochemistry