Determination of the interactions between lectins and glycoproteins by surface plasmon resonance

A simple and rapid analytical method for detecting interactions between oligosaccharides of glycoproteins and different lectins was studied by surface plasmon resonance using a biosensor (BIAcore). The interactions of three lectins, Sambucus sieboldiana agglutinin (SSA), Ricinus communis agglutinin I (RCA I) and Concanavalin A (Con A) for fetuin and digested fetuins with glycosidases, asialo-, agalacto-, and aglucosamino-fetuin, were investigated as a model system. These fetuins were immobilized to the matrix of of the sensor chip and the lectins were injected into the sensor chip cartridge. The association and dissociation reactions could be monitored as resonance signals in real time. The interactions with lectins significantly changed as the oligosaccharides of fetuin were trimmed. The interactions between fetuin and SSA, asialofetuin and RCA I, and aglucosaminofetuin and Con A show the highest affinity properties, respectively. The association constants of these lectins were estimated to be 1.4 x 10(7), 1.9 x 10(8) and 5.3 x 10(7) (M-1), respectively. These results suggested that the interactions between lectins and glycoproteins could be well defined in real time and kinetically, and that the partial structure of oligosaccharides of glycoproteins can be estimated by determination of the interactions with various lectins after glycosidase digestions using the biosensor.