Molecular modeling and NMR studies of benzyl substituted mannosyl trisaccharide binding to two mannose‐specific lectins: Allium sativam agglutinin I and Concanavalin A

Abstract

The interaction of trimannoside, α-benzyl 3, 6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside, 1 with ASAI (Allium sativam agglutinin I, garlic lectin) was studied to reveal the conformational preferences of this ligand in bound-state and detailed binding mode at atomic level. The binding phenomenon was then compared with another well-known mannose-binding lectin, ConA (Concanavalin A). Structural studies of the ligand in free state were done using NMR spectroscopy and Molecular Dynamics simulations. It is found that the substituted-trimannoside can undergo conformational transitions in solution, with one major and one minor conformation per glycosidic linkage (α 1→3 and α 1→6). On the other hand in the bound-state only one of the two major conformations was significantly populated. The role of phenyl ring in the binding process was explored. An extended binding site was observed for the trimannoside in ASAI utilizing the aromatic substituent, which is not seen in ConA. Binding data from difference absorption spectroscopy supported this fact that the binding of benzyl-substituted ligand is tighter with ASAI than ConA. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 952-967, 2010.

Characterization of antioxidant, anti-cancer, and immunomodulatory functions of partially purified garlic (Allium sativum L.) lectin

“…The garlic lectin exhibits leuco and hemagglutinating properties indicating its interaction with immune cells. Previous studies displays that the garlic lectin shows high affinity in binding to cells which contain oligomannosides and high mannose N-glycans on the cell surface (15). The garlic bulb in traditional medicine is connected to the health-promoting properties of this allium vegetable that may corresponds to some unique cellular modulation by the presence of garlic lectins.…”