Divergent Enzymatic Synthesis of a Comprehensive Type-1 Glycan Determinant Library

Type-1 glycan unit, Galβ1-3GlcNAc, is one of the two major backbones from which the large glycan determinant repertoire is derived. Numerous type-1 glycan determinants, including Lewis-series antigens, have been identified, often featuring fucosylation and sialylation. In this study, we achieved efficient synthesis of 30 type-1 determinants using a divergent enzymatic strategy. The synthetic efficiency of eight fucosyltransferases (FucTs) was evaluated for the installation of fucose at every step of the type-1 determinant synthesis. Using selected FucTs and a few additional robust glycosyltransferases, 22 basic type-1 determinants were constructed at preparative scales in no more than three steps, starting from the type-1 unit. Additionally, 8 extended type-1 Lewis antigens were successfully synthesized in no more than five steps. Subsequent glycan microarray assays of these glycan determinants revealed intriguing recognitions by glycan-binding proteins and anti-type-1 Lewis antigen monoclonal antibodies.