pH-Responsive Bioactive Glycopolypeptides with Enhanced Helicity and Solubility in Aqueous Solution

Copolypeptides of l-glutamate and glucosylated l-/dl-allyl- or dl-propargylglycine were synthesized by ring-opening polymerization and thiol–ene/yne photochemistry in aqueous solution, allowing the mild introduction of sugar units (here, glucose) in the final step. The glucosylated and non-glucosylated samples adopt a random-coil conformation in neutral and basic media and an α-helical conformation in acidic media, the helical content depending on the number and configuration of allyl-/propargylglycine units. The glucocopolypeptides unveil enhanced helical stability and solubility down to pH 3.5. Turbidity assays proved the selective binding of the polymers to the plant lectin concanavalin A.