Département de chimie moléculaire

Carbohydrate-protein interactions play key roles in a wide variety of biol. processes. These interactions are usually weak, with dissocn. consts. in the low millimolar to high micromolar range. Nature uses multivalency to reach high avidities via the glycoside cluster effect. Capitalizing on this effect, numerous synthetic multivalent glycoconjugates have been described and used as ligands for carbohydrate-binding proteins. However, valency is only one of several parameters governing the binding mechanisms which are different for every biol. receptor, making it almost impossible to predict. In this context, ligand optimization requires the screening of a large no. of structures with different valency, rigidity/flexibility, architecture. The authors describe a screening platform based on a glycodendrimer array and its use to det. the key parameters for high affinity ligands of lectin. Several glycoclusters and glycodendrimers displaying varying nos. of $\alpha$-N-acetylgalactosamine residues were covalently attached on glass slides and their binding was studied with the fluorophore-functionalized Helix pomatia agglutinin (HPA) used as a lectin model. This technique requires minimal quantities of glycoconjugate compared to other techniques and affords useful information on the binding strength. Building of the glycodendrimer array and quantification of the interactions with HPA are described. [on SciFinder(R)]