Thermodynamics of lectin-sugar interaction: Binding of sugars to winged bean (Psophocarpus

Abstract Combining site of WBAI is extended and encompasses all the residues of blood group A-reactive trisaccharide [GalNAccrl3GalfMGlc]. Though both of the fucose residues of A-pentasaccharide [GalNAcol(Fucd2)3Gale(FucoL3)4Glc] do not directly interact with the combining site they thermodynamically favour the interaction of GalNAca3Galp4Glc part of the molecule by imposing a sterically favourable orientation of the binding epitope & GalNAcd3Galb4Glc of the saccharide. Binding of sugars is driven by enthalpy and is devoid of heat capacity changes. This together with enthalpy-entropy compensation observed for these processes underscore the importance of water reorganization as being one of the principal determinant of protein-sugar interactions. Recognition is a key event in many biological phenomena. It is also an initiation step in numerous processes, based on cell-cell interactions, such as fertilization, embryogenesis, organ formation