DIFFERENTIAL SCANNING CALORIMETRIC STUDIES OF THE GLYCOPROTEIN, WINGED BEAN ACIDIC LECTIN, ISOLATED FROM THE SEEDS OF PSOPHOCARPUS-TETROGONOLOBUS

Differential scanning calorimetry of solutions of WBAII and in presenc e of sugar ligands shows that WBAII dimer dissociates to its constitue nt monomeric subunits at the denaturation temperature, The thermal den aturation of WB;UI consists of the unfolding of two independent domain s of WBAII similar to that of basic winged bean lectin and ECorL and i n contrast to concanavalin A (conA), pea and lentil lectin, which unfo ld as single entities. Apparently, the glycosylation reduces the struc tural integrity of WBAII as compared to conA, pea and lentil Lectin, T he increase in the denaturation temperature of the sugar-lectin comple xes yields binding constants close to the binding constants extrapolat ed from the ITC results and confirms the mechanism proposed for its th ermal unfolding. (C) 1998 Federation of European Biochemical Societies .