Chemical Synthesis of L-Fucose Derivatives for Acceptor Specificity Characterisation of Plant Cell Wall Glycosyltransferases

摘要

abstract_textpSeven derivatives of L-fucose: methyl alpha-L-fucopyranoside, methyl 2-O-methyl-alpha-L-fucopyranoside, methyl 3-O-methyl-alpha-L-fucopyranoside, methyl 4-O-methyl-alpha-L-fucopyranoside, alpha-L-fucopyranosyl-(1 - 4)-alpha/beta-L- rhamnopyranose, methyl alpha-L-fucopyranosyl-(1 - 4)-alpha-L-rhamnopyranoside and methyl alpha-L-fucopyranosyl-(1 - 4)-beta-L-rhamnopyranoside, were chemically synthesized and characterized. The derivatives of L-fucose were designed to mimic the L-fucose moieties present in the A-chain of pectic rhamnogalacturonan-II and used to investigate the regiospecificity of three heterologously expressed xylosyltrans-ferases from Arabidopsis thaliana. The monosaccharide methyl alpha-L-fucopyranoside was the most efficient acceptor, 30 fold more effective than methyl 4-O-methyl-alpha-L-fucopyranoside. O-methylation in position 2 or 3 abolished acceptor function. The efficiencies of the disaccharides as acceptors were methyl alpha-L-fucopyranosyl-(1 - 4)-beta-L-rhamnopyranoside alpha-L-fucopyranosyl-(1 - 4)-alpha/beta-L-rhamnopyranose methyl alpha-L-fucopyranosyl(1 - 4)-alpha-L-rhamnopyranoside. These findings demonstrate the utility of acceptor derivatives as probes of glycosyltransferase regiospecificity./p/abstract_text