Identification of alpha-galactosyl epitope mimetics through rapid generation and screening of C-linked glycopeptide library.
A general methodology has been established for rapid generation and screening of combinatorial glycopeptide library and subsequent mass spectrometric sequencing to identify the mimetics of Galalpha(1,3)Gal epitopes. Using this approach, several active glycopeptide sequences were recognized and found to inhibit the binding of human natural anti-Gal antibodies with comparable IC(50)s to synthetic Galalpha(1,3)Gal oligosaccharides. The most active glycopeptides detected from the library included Gal-Tyr-Trp-Arg-Tyr, Gal-Thr-Trp-Arg-Tyr, and Gal-Arg-Trp-Arg-Tyr. These glycopeptides showed higher affinities to anti-Gal antibodies than known Galalpha(1,3)Gal peptide mimetics, such as DAHWESWL and SSLRGF. Our results suggest that, by combining a peptide sequence (the "functional" mimic part) with a terminal alpha-linked galactose moiety (the "structural" mimic part), the resulting glycopeptide could be a very good Galalpha(1,3)Gal mimetic. Analysis of these active glycopeptides provided first-hand information regarding the binding site of anti-Gal antibodies to facilitate the structurally based design of more potent and stable inhibitors.
Xian
Ming
M
Department of Biochemistry and Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
Fatima
Zakia
Z
Zhang
Wei
W
Fang
Jianwen
J
Li
Hanfen
H
Pei
Dehua
D
Loo
Joseph
J
Stevenson
Tracy
T
Wang
Peng George
PG
D000818:Animals; D002240:Carbohydrate Sequence; D020650:Combinatorial Chemistry Techniques; D018360:Crystallography, X-Ray; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry*; D005690:Galactose / Q000737:chemistry*; D006020:Glycopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D007070:Immunoglobulin A / Q000737:chemistry; D007074:Immunoglobulin G / Q000737:chemistry; D007075:Immunoglobulin M / Q000737:chemistry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009844:Oligosaccharides / Q000737:chemistry; D019151:Peptide Library; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000939:Epitopes; D006020:Glycopeptides; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007202:Indicators and Reagents; D009844:Oligosaccharides; D019151:Peptide Library; D005690:Galactose