Use of a biosensor based on surface plasmon resonance and biotinyl glycans for analysis of sugar binding specificities of lectins.

We have developed a new method for analysis of the interaction between lectins and biotin-derivatized oligosaccharides involving a biosensor based on surface plasmon resonance. Complex type asialo-bi-, tri-, and tetra-antennary oligosaccharides were quantitatively converted into their biotin derivatives by incubating them with 6-(D-biotinyl)-aminohexanoyl hydrazide. This method was also applicable to sialyl sugar chains without any removal of sialic acid residues. The reaction mixture could be directly injected onto the streptavidin pre-immobilized surface of a sensor chip without any purification because of its fairly low reagent/carbohydrate molar ratio. The amounts of sugar chains required for interaction analysis by this method were as low as 1 pmol. The binding specificities of Sambucus sieboldiana lectin, Maackia amurensis lectin, Ricinus communis agglutinin-120 (RCA120), and concanavalin A could be rapidly determined qualitatively by this method. Furthermore, kinetic analysis of the interaction between RCA120, and complex type asialo-bi-, tri-, and tetra-antennary oligosaccharides revealed that both the association rate constant and the dissociation rate constant (kdiss) decreased with increasing numbers of terminal galactosyl residues. Because the tendency observed for kdiss paralleled the elution order of these oligosaccharides on RCA120 immobilized affinity chromatography, kiss might hold the key to determination of the elution order on affinity chromatography.