Synthesis of a Fluorescent Ganglioside GM1 Derivative and Screening of a Synthetic Peptide Library for GM1 Binding Sequence Motifs

Abstract

A ganglioside GM1 probe bearing a dark-red fluorescent dye at the sphingosine moiety of the molecule was prepared by a convenient one-pot synthesis. The labeled GM1 permitted the detection of the natural ganglioside GM1 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 GM1 affinity could be identified. We consider the labeled glycolipid described herein a versatile tool for manifold biochemical investigations.