Specific binding of GM1-binding peptides to high-density GM1 in lipid membranes.
The ganglioside Galbeta1-3GalNAcbeta1-4(Neu5Acalpha2-3)Galbeta1-4Glcbeta1-1'Cer (GM1) is an important receptor. We have previously identified GM1-binding peptides based on affinity selection from a random peptide library. In the present study, we determined the amino acids essential for binding GM1 and investigated the specific interaction with GM1 in the lipid membrane. Arginines and aromatic amino acids in the consensus sequence (W/F)RxL(xP/Px)xFxx(Rx/xR)xP contributed to the ability of the peptides to bind GM1. The peptide p3, VWRLLAPPFSNRLLP, having the consensus sequence, showed high affinity for GM1 with a dissociation constant of 1.2 microM. Furthermore, the density-dependent binding of p3 was investigated using mixed monolayers of GM1 and Glcbeta1-1'Cer (GlcCer). p3 binds preferentially to high-density GM1, and its interaction with GM1 was found to be cooperative based on a Hill plot. These results indicated that a lateral assembly of GM1 molecules was required for the recognition of carbohydrates by p3. The GM1-binding peptide played a role as a unique anti-GM1 probe differing from the cholera toxin B subunit or antibodies.
Matsubara
Teruhiko
T
Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan.
Iijima
Kazutoshi
K
Nakamura
Miwa
M
Taki
Takao
T
Okahata
Yoshio
Y
Sato
Toshinori
T
D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D001667:Binding, Competitive; D002772:Cholera Toxin / Q000737:chemistry; D005677:G(M1) Ganglioside / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011791:Quartz
D008051:Lipid Bilayers; D008055:Lipids; D010455:Peptides; D011791:Quartz; D005677:G(M1) Ganglioside; D002772:Cholera Toxin; D001120:Arginine