Département de chimie moléculaire

Protein (lectin/toxin)-glycan interaction can be clin. harmful so that the design of inhibitors has become an aim. Cyclic decapeptides are suited as rigid carriers for carbohydrate derivs. We herein document the bioactivity of sugar headgroups covalently attached to this carrier for the cases of five proteins, i.e. a potent biohazardous plant agglutinin, a leguminous model lectin and three adhesion/growth-regulatory human lectins. They represent the different types of topol. organization within the galectin family. The relative inhibitory activities of glycoclusters with the three ligands (galactose, lactose and the disaccharide of the Thomsen-Friedenreich antigen) reflected the affinity of free carbohydrates, hereby excluding an impairment of binding activity by chem. derivatization and conjugation. Headgroup tailoring is thus one route to optimize activity and selectivity of cyclopeptide-based glycoclusters. The increase of ligand d. from tetra- to hexadecavalency added a second route. The plant toxin and tandem-repeat-type galectin-4 were esp. sensitive to this parameter change. Strategically combining solid-phase assays for screening with anal. of lectin binding to cells in different systems revealed efficient inhibition by distinct glycoclusters, thereby protecting cells from lectin assocn. Cyclic neoglycodecapeptides thus warrant further study as lectin-directed pharmaceuticals. Copyright © 2011 European Peptide Society and John Wiley {&} Sons, Ltd. [on SciFinder(R)]