Glycosyl fluorides can function as substrates for nucleotide phosphosugar-dependent glycosyltransferases.
alpha-Galactosyl fluoride is shown to function as a substrate, in place of uridine-5'-diphosphogalactose, for the alpha-galactosyltransferase from Neisseria meningitidis. The reaction only occurs in the presence of catalytic quantities of uridine 5'-diphosphate. In the presence of galactosyl acceptors, the expected oligosaccharide product is formed in essentially quantitative yields, reaction having been performed on multi-milligram scales. In the absence of a suitable acceptor, the enzyme synthesizes uridine-5'-diphosphogalactose, as demonstrated through a coupled assay in which uridine-5'-diphosphogalactose is converted to uridine-5'-diphosphoglucuronic acid with conversion of NAD to NADH. These glycosyl fluoride substrates therefore offer the potential of an inexpensive alternative donor substrate in the synthesis of oligosaccharides as well a means of generating steady state concentrations of nucleotide diphosphate sugars for in situ use by other enzymes. Further, they should prove valuable as mechanistic probes.
Lougheed
B
B
Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1.
Ly
H D
HD
Wakarchuk
W W
WW
Withers
S G
SG
D005459:Fluorides / Q000378:metabolism*; D016695:Glycosyltransferases / Q000378:metabolism*; D007700:Kinetics; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014531:Uridine Diphosphate Galactose / Q000378:metabolism*
D011994:Recombinant Proteins; D014531:Uridine Diphosphate Galactose; D016695:Glycosyltransferases; D005459:Fluorides