αGal-conjugated anti-rhinovirus agents: chemo-enzymatic syntheses and testing of anti-Gal binding

Abstract

The syntheses of αGal-conjugated anti-rhinovirus agents 1, 2 and 3 and their abilities to inhibit αGal binding of human anti-Gal antibody are described. An efficient enzymatic glycosylation using a novel fusion protein serves to provide the key αGal intermediate 7, which is elaborated to αGal amines 9, 12 and 14 with various tethers. The conjugates are then formed by amide coupling of these amines to heterocyclic acid 18 in the presence of 1,1′-carbonyldiimidazole (CDI), followed by deprotection of the αGal part. Conjugate 3 having a triethylene glycol linker displays the highest binding affinity to human anti-Gal antibody as tested by ELISA.