earticle

영어

Surface plasmon resonance (SPR) can provide a kinetic information for an interaction and rapidly monitor any dynamic process, such as adsorption or degradation, without the need for any sample preparation. Herein, we used SPR system to analyze carbohydrate-protein interaction, especially, Vibriocholeratoxin-GM1pentasaccharide. The understanding of carbohydrate contribution in carbohydrate-protein interaction may provide meaningful information about carbohydrate-related biological system. Interaction between ctxA and ctxB is firstly investigated in this study since the binding is a prerequisite for virulence mechanism. Interaction kinetics between ctxB and GM1 pentasaccharide using the our proposed saccharide immobilization method were evaluated, and the results showed similar degree of kinetics to the previous reports, therefore our direct immobilization could make SPR analysis simply for carbohydrate-related researches. And the introduction of ctxA during the interaction showed higher affinity than that of ctxB-GM1 although KD constant was 10-times lower than ctxB-GM1 binding. Comparative analyses for GM1 analogues-ctxAB were conducted in order to evaluate kinetic values from structural differences. Although these results did not show significant difference, determination of the association constants for ctxAB revealed the following order: LST-b > GM3 > LST-a > asialo GM1 and dissociation constants for ctxAB showed following order: LST-b > asialo GM1 > LST-a > GM3. These results indicate that sialic acid thumb is sufficient for recognition, and the terminal glalactose and GalNAc finger are required to stabilize the ctxAB-ganglioside GM1 interaction. Collectively, direct immobilization of carbohydrate at SPR-based analytical system can evaluate structural contribution of carbohydrate moieties in carbohydrate-protein interaction as well as provide valuable information for understanding the interactions.