Structure and function of oligosaccharide-binding peptides that selected from random libraries

The peptides that bind to oligosaccharide of glycolipid were identified and their function was assayed. The monolayers of ganglioside were employed for an affinity selection by phage-displayed random libraries, and the ganglioside-binding peptides were selected. A synthetic peptide p3 inhibited the cholera toxin binding to GM1 (Galβ1-3GalNAcβ1-4(Neu5Acα2-3) Galβ1-4Glcβ1-1′Cer) with IC₅₀ of 1 μM. A raft-like hybrid lipid bilayer was prepared and the binding of the peptide were visualized by atomic force microscopy, indicated that the peptide was specific to glycocluster in the lipid membrane. Furthermore, GM3 (Neu5Acα2- 3Galβ1-4Glcβ1-1′′Cer)-binding peptides bound to cells and the corresponding N-stearoyl derivatives inhibited the infection of Madin-Darby canine kidney cells by influenza virus, which recognizes α2,3- and α2,6-linked sialylgalactose structures.