@article { ISI:000238665500010, title = {Synthesis of a library of xylogluco-oligosaccharides for active-site mapping of xyloglucan endo-transglycosylase}, journal = {JOURNAL OF ORGANIC CHEMISTRY}, volume = {71}, number = {14}, year = {2006}, month = {JUL 7}, pages = {5151-5161}, type = {Article}, abstract = {{[}GRAPHICS] Complex oligosaccharides containing R-D-xylosyl-(1 -> 6)-beta-D-glucosyl residues and unsubstituted beta-(1 -> 4)-linked D-glucosyl units were readily synthesized using enzymatic coupling catalyzed by the Cel7B E197A glycosynthase from Humicola insolens. Constituting this library required four key steps: ( 1) preparing unprotected building blocks by chemical synthesis or enzymatic degradation of xyloglucan polymers; (2) generating the donor synthon in the enzymatic coupling by temporarily introducing a lactosyl motif on the 4-OH of the terminal glucosyl units of the xylogluco-oligosaccharides; ( 3) synthesizing the corresponding R-fluorides, followed by their de-O-acetylation and the glycosynthase-catalyzed condensation of these donors onto various acceptors; and (4) enzymatically releasing lactose or galactose from the reaction product, affording the target molecules in good overall yields. These complex oligosaccharides proved useful for mapping the active site of a key enzyme in plant cell wall biosynthesis and modification: the xyloglucan endo-transglycosylase (XET). We also report some preliminary enzymatic results regarding the efficiency of these compounds.}, issn = {0022-3263}, doi = {10.1021/jo0525682}, author = {Faure, Regis and Saura-Valls, Marc and Brumer, Harry and Planas, Antoni and Cottaz, Sylvain and Driguez, Hugues} }