Selective bioorthogonal probe for N-glycan hybrid structures

Abstract Metabolic incorporation of chemically tagged monosaccharides is a facile means of labelling cellular glycoprotein and glycolipids. Yet, since the monosaccharide precursors are often shared by several pathways, selectivity has been difficult to attain. For example, N -linked glycosylation is a chemically complex, and ubiquitous post translational modification with three distinct classes of GlcNAc-containing N -glycan structures: oligomannose, hybrid, and complex. Here we describe synthesis of 1,3-Pr 2 -6-OTs GlcNAlk as a next generation metabolic chemical reporter (MCR) for the specific labeling of hybrid N -glycan structures. We first developed a general strategy for defining the selectivity of labelling with chemically tagged monosaccharides. We then applied this approach to establish that 1,3-Pr 2 -6-OTs GlcNAlk is specifically incorporated into hybrid N -glycans. Using this MCR as a detection tool, we carried out imaging experiments to define the intracellular localization and trafficking of target proteins bearing hybrid N -glycan structures.