Synthesis of 1-N-glycyl beta-oligosaccharide derivatives. Reactivity of Lens culinaris lectin with a fluorescent labeled streptavidin pseudoglycoprotein and immobilized neoglycolipid.

Abstract

The lectin from Lens culinaris (lentil) has a binding specificity for glycopeptides bearing 6-O-linked fucose on the reducing terminus on complex-type N-linked oligosaccharides. Lentil lectin therefore provides an excellent example of a carbohydrate binding protein in which high-affinity interactions are dependent on the integrity of the oligosaccharide core structure. We report here the synthesis of the 1-N-glycyl beta-derivative of Gal beta 4GlcNAc beta 2Man alpha 6(Gal beta 4GlcNAc beta 2Man alpha 3)Man beta 4GlcNAc beta 4(Fuc alpha 6)-GlcNAc (Gal-2F) and its subsequent biotinylation and palmitoylation. The biotin derivative when bound to a streptavidin-fluorescein isothiocyanate (FITC) conjugate was able to bind to both concanavalin A (ConA) and lentil lectin affinity columns. In contrast, synthesis of the biotin derivative of the glycamine derivative of Gal-2F and subsequent binding to streptavidin-FITC afforded reactivity to a ConA affinity column but not to a lentil lectin affinity column. Lentil lectin also bound to plastic microtiter plates containing the adsorbed palmitoyl-1-N-glycyl beta-derivative. No binding occurred when the homologous glycamine neoglycolipid was used. These results suggest the 1-N-glycyl beta-derivative of oligosaccharides may have general utility as an intermediate in the synthesis of novel glycoconjugate probes.