Small molecules containing hetero-bicyclic ring systems compete with UDP-Glc for binding to WaaG glycosyltransferase.
The α-1,3-glucosyltransferase WaaG is involved in the synthesis of the core region of lipopolysaccharides in E. coli. A fragment-based screening for inhibitors of the WaaG glycosyltrasferase donor site has been performed using NMR spectroscopy. Docking simulations were performed for three of the compounds of the fragment library that had shown binding activity towards WaaG and yielded 3D models for the respective complexes. The three ligands share a hetero-bicyclic ring system as a common structural motif and they compete with UDP-Glc for binding. Interestingly, one of the compounds promoted binding of uridine to WaaG, as seen from STD NMR titrations, suggesting a different binding mode for this ligand. We propose these compounds as scaffolds for the design of selective high-affinity inhibitors of WaaG. Binding of natural substrates, enzymatic activity and donor substrate selectivity were also investigated by NMR spectroscopy. Molecular dynamics simulations of WaaG were carried out with and without bound UDP and revealed structural changes compared to the crystal structure and also variations in flexibility for some amino acid residues between the two WaaG systems studied.
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden.
Jens
J
Landström
Karina
K
Persson
Christoph
C
Rademacher
Magnus
M
Lundborg
Warren
W
Wakarchuk
Thomas
T
Peters
Göran
G
Widmalm
D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D006017:Glycolipids / Q000096:biosynthesis; D008024:Ligands; D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D014539:Uridine Diphosphate Sugars / Q000737:chemistry* / Q000378:metabolism
D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D006017:Glycolipids; D008024:Ligands; D014539:Uridine Diphosphate Sugars; D005964:Glucosyltransferases; C098465:WaaG protein, E coli