Hydrolytically Stable Bioactive Synthetic Glycopeptide Homo- and Copolymers by Combination of NCA Polymerization and Click Reaction

Abstract

The synthesis of poly(dl-propargylglycine) and poly(γ-benzyl-l-glutamate-co-dl-propargylglycine) was performed by NCA polymerization at 0 °C to yield well-defined polypeptides with polydispersity indices below 1.3. FTIR results confirm β-sheet and α-helical conformation of the homopolymer and copolymer, respectively. The subsequent glycosylation was achieved by Huisgen [3 + 2] cylcoaddition (“click” reaction) with azide-functional galactose. FTIR, NMR, SEC, and MALDI−ToF analyses verify the successful glycosylation and suggest a high efficiency of the click reaction. The homoglycopeptide was found to be water-soluble and to form aggregates in water above a critical concentration of 0.079 mg/mL. Selective lectin binding experiments confirmed that the glycopeptides can be used in biorecognotion applications. Moreover, the selective hydrolysis of the benzyl ester groups in the copolymer was achieved without loss of the galactose.