Application of a Multivalent Glycoprobe: Characterization of Sugar-Binding Specificity of Siglec Family Proteins

This chapter describes how the glycoprobe was prepared and then applied to the characterization of the binding specificity of sialic acid-binding Ig-like lectins (Siglecs). Siglecs () are a family of lectins expressed mainly on hematopoietic cells. The binding of Siglecs to specific sialoglycoconjugates is associated with their specific functions, for example, cellular attachment or recognition. The interaction of Siglecs with sialoglycoconjugates on the cell surface may comprise an initial step in the process of cellular attachment or recognition. The interaction is believed to occur in a multivalent manner that is, an array of Siglecs on the cell surface binds multiple sialoglycoconjugates on the recognized cells. To characterize the multivalent interaction of Siglecs, a polyvalent “glycoprobe” that carries more than 100 oligosaccharides was developed. Glycochain structures of gangliosides and oligosaccharides and their recognition by Siglecs are tabulated. The chapter discusses the preparation and polymerization of oligosaccharyl streptavidin, the assay for adherent cells, and suspension assay of Siglecs.