Author(s): Srivastava OP, Hindsgaul O, Shoreibah M, Pierce M
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Abstract Six analogs of the trisaccharide 8-methoxycarbonyloctyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D-mannopyrano syl] -beta-D-mannopyranoside (3), a previously reported acceptor for N-acetylglucosaminyltransferase-V (GnT-V) have been chemically synthesized and evaluated as GnT-V acceptors. Replacement of the beta-D-man rho-O(CH2)8COOMe "reducing end" of 3 by beta-D-Glc rho-O(CH2)7 CH3 gave octyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl]-alpha-D- mannopyranosyl)-beta-D-glucopyranoside (5) whose activity was indistinguishable from that of 3. Removal of the 4-OH group of the beta-D-Glc residue in 5 had little effect on the activity, while the corresponding 4-O-methyl derivative was twice as active. Replacement of the C-6 pro-R hydrogen of the same residue by a methyl group gave the L-glycero-D-gluco derivative 8, whereas replacement of the corresponding pro-S hydrogen gave the D-glycero-D-gluco compound 9. Trisaccharide 8, whose rotameric distribution about the C-5-C-6 bond is sterically biased towards the gg conformation was less than half as active as 5 as a GnT-V acceptor, whereas 9, which is biased towards the gt conformation, was more than twice as active. These results provide evidence for the conformational control of oligosaccharide biosynthesis.
This article was published in Carbohydr Res
and referenced in Journal of Glycomics & Lipidomics