10.1021/jo0525682.s001 Régis Fauré Régis Fauré Marc Saura-Valls Marc Saura-Valls Harry Brumer Harry Brumer Antoni Planas Antoni Planas Sylvain Cottaz Sylvain Cottaz Hugues Driguez Hugues Driguez Synthesis of a Library of Xylogluco-Oligosaccharides for Active-Site Mapping of Xyloglucan <i>endo</i>-Transglycosylase American Chemical Society 2006 chemical synthesis enzyme Synthesi oligosaccharide degradation compound OH yield unsubstituted terminal glucosyl units fluoride reaction product Humicola insolens donor synthon enzymatically residue XET plant cell wall biosynthesis lactosyl motif efficiency acceptor galactose building blocks synthesizing Cel 7B E 197A glycosynthase xyloglucan polymers Constituting site target molecules Mapping modification mapping condensation lactose Xyloglucan 2006-07-07 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Synthesis_of_a_Library_of_Xylogluco_Oligosaccharides_for_Active_Site_Mapping_of_Xyloglucan_i_endo_i_Transglycosylase/3071878 Complex oligosaccharides containing α-d-xylosyl-(1→6)-β-d-glucosyl residues and unsubstituted β-(1→4)-linked d-glucosyl units were readily synthesized using enzymatic coupling catalyzed by the Cel7B E197A glycosynthase from <i>Humicola insolens</i>. 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 α-fluorides, followed by their de-<i>O</i>-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 <i>endo</i>-transglycosylase (XET). We also report some preliminary enzymatic results regarding the efficiency of these compounds.