Synthesis of a fluorescent ganglioside GM1 derivative and screening of a synthetic peptide library for GM1 binding sequence motifs

A ganglioside G(M1) probe bearing a dark-red fluorescent dye at the sphingosine moiety of the molecule was prepared by a convenient one-pot synthesis. The labeled G(M1) permitted the detection of the natural ganglioside G(M1) ligand Escherichia coli heat-labile enterotoxin subunit B (EtxB) in picomole quantities on a solid support. When an epitope mapping of several ganglioside binding proteins and protein fragments was performed by screening a cellulose membrane-bound synthetic library of 64 16mer peptides with the new probe, several peptides displaying ganglioside G(M1) affinity could be identified. We consider the labeled glycolipid described herein a versatile tool for manifold biochemical investigations.