Selection of ganglioside GM1-binding peptides by using a phage library

Ganglioside Gal beta 1 --> 3GalNAc beta 1 --> 4(NeuAc alpha 2 --> 3) Gal beta 1 --> 4Glc beta 1 --> 1'Cer (GM1)-binding peptides were obtained from a phage-displayed pentadecapeptide library by an affinity selection. The selection processes were in situ-monitored by a quartz-crystal microbalance method, on which a ganglioside GM1 monolayer was transferred. After five rounds of biopanning, the DNA sequencing of 18 selected phages showed that only three individual clones were selected, The peptide sequences of the random region were found to be DFRRLPGAFWQLRQP, GWWYKGRARPVSAVA and VWRLLAPPFSNRLLP. Binding constants of these phage clones to the GM1 monolayer were 10(10) M-1. Three synthetic pentadecapeptides inhibited the binding of cholera toxin B subunit to the GM1 monolayer with an IC50 of 24, 13 and 1.0 mu M, respectively. These peptides will be useful for searching functional roles of ganglioside GM1. (C) 1999 Federation of European Biochemical Societies.