Construction of N-Glycan Microarrays by Using Modular Synthesis and On-Chip Nanoscale Enzymatic Glycosylation

An effective chemoenzymatic strategy is reported that has allowed the construction, for the first time, of a focused microarray of synthetic N glycans Based on modular approaches, a variety of N-glycan core structures have been chemically synthesized and covalently immobilized on a glass sur face The printed structures were then enzymatically diversified by the action of three different glycosyltransferases in nanodroplets placed on top of individual spots of the microarray by a printing robot Conversion was followed by lectin binding specific for the terminal sugars This enzymatic extension of surface bound ligands in nano droplets reduces the amount of precious glycosyltransferases needed by seven orders of magnitude relative to reactions carried out in the solution phase Moreover, only those ligands that have been shown to be substrates to a specific glycosyltransferase can be individually chosen for elongation on the array The methodology described here combining focused modular synthesis and nanoscale on chip enzymatic elongation could open the way for the much needed rapid construction of large synthetic glvcan arrays