Interactions of aromatic mannosyl disulfide derivatives with Concanavalin A: synthesis, thermodynamic and NMR spectroscopy studies

alpha-D-Mannopyranosyl units were attached to an aromatic scaffold through disulfide linkages to obtain mono- to trivalent glycosylated ligands for lectin binding studies. Isothermal titration calorimetric (ITC) measurements indicated that binding affinities of these derivatives to Concanavalin A (Con A) were comparable to or slightly higher than that of methyl alpha-D-mannopyranoside (K-a values in the range of 10(4) M-1). The stoichiometries of the lectin-ligand complexes were in agreement with the formal valencies (1-3) of the respective ligands indicating cross-linking in interactions with the di- and trivalent derivatives. Multivalency effects could not, however, be observed with the latter. These ligands were shown to bind to the carbohydrate binding site of Con A using saturation transfer difference (STD) NMR competition experiments. (C) 2009 Elsevier Ltd. All rights reserved.