Carbohydrate recognition by pentadecapeptide ligands for a series of sialylated oligosaccharides

Sialyloligosaccharides of glycoproteins and glycosphingolipids play important roles in biological events on cell membranes. GT1b is a ganglioside having a trisialyloligosaccharide and is a receptor for tetanus toxin. In the present study, pentadecapeptide ligands for GT1b were obtained by phage display selection from a random peptide library with the use of a GT1b monolayer. The artificial pentadecapeptides had high affinity for GT1b which tended to increase depending on the number of sialic acids in sialyloligosaccharides. Arg, Ser, and hydrophobic amino acids were found in a consensus motif and may contribute to carbohydrate recognition. The consensus motif of the GT1b-binding peptides was different from that of GM1-, GM2-, GM3-, or GD1a-binding peptides. Peptide ligands for GT1b should be investigated for trisialyloligosaccharide functions and the development of therapeutic agents against trisialyloligosaccharide-related diseases.