The structural basis of substrate promiscuity in UDP-hexose 4-epimerase from the hyperthermophilic Eubacterium Thermotoga maritima

Archives of Biochemistry and Biophysics
Sun-Mi ShinDong-Woo Lee

Abstract

UDP-galactose 4-epimerase (GalE) catalyzes the interconversion of UDP-glucose (UDP-Glc) and UDP-galactose (UDP-Gal), which is a pivotal step in the Leloir pathway for d-galactose metabolism. Although GalE is widely distributed in prokaryotes and eukaryotes, little information is available regarding hyperthermophilic GalE. We overexpressed the TM0509 gene, encoding a putative GalE from Thermotoga maritima (TMGalE), in Escherichia coli and characterized the encoded protein. To further investigate the molecular basis of this enzyme's catalytic function, we determined the crystal structures of TMGalE and TMGalE bound to UDP-Glc at resolutions of 1.9 Å and 2.0 Å, respectively. The enzyme was determined to be a homodimer with a molecular mass of 70 kDa. The enzyme could reversibly catalyze the epimerization of UDP-GalNAc/UDP-GlcNAc as well as UDP-Gal/UDP-Glc at elevated temperatures, with an apparent optimal temperature and pH of 80 °C and 7.0, respectively. Our data showed that TM0509 is a UDP-galactosugar 4-epimerase involved in d-galactose metabolism; consequently, this study provides the first detailed characterization of a hyperthermophilic GalE. Moreover, the promiscuous substrate specificity of TMGalE, which is more similar to...Continue Reading

References

Nov 15, 2001·Cellular and Molecular Life Sciences : CMLS·S T AllardJ H Naismith
Dec 2, 2004·Acta Crystallographica. Section D, Biological Crystallography·Paul Emsley, Kevin Cowtan
Oct 11, 2005·Nucleic Acids Research·Ross OverbeekVeronika Vonstein
Aug 8, 2007·Journal of Molecular Biology·Evgeny Krissinel, Kim Henrick
Jan 9, 2010·Acta Crystallographica. Section D, Biological Crystallography·Alexei Vagin, Alexei Teplyakov
Apr 5, 2011·Acta Crystallographica. Section D, Biological Crystallography·Garib N MurshudovAlexei A Vagin

❮ Previous
Next ❯

Related Concepts

Related Feeds

African Trypanosomiasis

African trypanosomiasis, also known as sleeping sickness, is an insect-borne parasitic disease of humans and other animals. It is caused by protozoa of the species Trypanosoma brucei and almost invariably progresses to death unless treated. Discover the latest research on African trypanosomiasis here.

Archaeogenetics

Recent advances in genomic sequencing has led to the discovery of new strains of Archaea and shed light on their evolutionary history. Discover the latest research on Archaeogenetics here.

Bacterial Protein Structures

Bacterial protein structures can expedite the development of novel antibiotics. Here is the latest research on bacterial proteins and the resolution of their structures.

Bacterial Protein Structures (ASM)

Bacterial protein structures can expedite the development of novel antibiotics. Here is the latest research on bacterial proteins and the resolution of their structures.