Con A lectin binding by synthetic bivalent arabinomannan tri- and pentasaccharides reveals connectivity-dependent functional valencies.

Lectin Con A, with specificity to interact with α-d-mannopyranoside, achieves tight binding affinity with the aid of optimal multivalent ligand valencies, distances and orientations between the ligands. A series of synthetic arabinomannans, possessing arabinan core and mannan at the non-reducing ends, is studied to assess the above constraints involved with lectin binding in this report. Trisaccharides, with (1 → 2)(1 → 3), (1 → 2)(1 → 5) and (1 → 3)(1 → 5) glycosidic bond connectivities, and a pentasaccharide with mannopyranosides at the non-reducing ends are synthesized.

Surface Density of Ligands Controls In-Plane and Aggregative Modes of Multivalent Glycovesicle-Lectin Recognitions.

Glycovesicles are ideal tools to delineate finer mechanisms of the interactions at the biological cell membranes. Multivalency forms the basis which, in turn, should surpass more than one mechanism in order to maintain multiple roles that the ligand-lectin interactions encounter. Ligand densities hold a prime control to attenuate the interactions.

Surface Ligand Density Switches Glycovesicles between Monomeric and Multimeric Lectin Recognition.

Carbohydrate-protein interactions define a multitude of cellular recognition events. We present herein synthetic glycovesicles as cell-surface mimics in order to switch the nature of lectin recognition. The covalent glycovesicles, constituted with diacetylene monomers of various ligand densities at their surfaces, are prepared through photo-polymerization.

The barley lectin, horcolin, binds high-mannose glycans in a multivalent fashion, enabling high-affinity, specific inhibition of cellular HIV infection.

-Linked glycans are critical to the infection cycle of HIV, and most neutralizing antibodies target the high-mannose glycans found on the surface envelope glycoprotein-120 (gp120). Carbohydrate-binding proteins, particularly mannose-binding lectins, have also been shown to bind these glycans. Despite their therapeutic potency, their ability to cause lymphocyte proliferation limits their application.