Synthesis of modified Trichinella spiralis disaccharide epitopes and a comparison of their recognition by chemical mapping and saturation transfer difference NMR.
A rat monoclonal antibody 9D4 raised against the cell surface N-glycan of the parasite Trichinella spirallis protects rats against further infection. The terminal disaccharide β-d-Tyvp(1→3)β-d-GalNAcp (2) represents the immunodominant portion of the antigenic determinant. Chemical mapping of the antibody binding site by functional group modification employing monodeoxy and mono-O-methyl congeners identified key polar contacts and topography of the bound disaccharide. We report here a comparison of the chemical mapping studies with the antigen topography inferred from saturation transfer difference (STD) NMR experiments. During chemical mapping several congeners of compound 2 showed substantially enhanced binding. Pairing of these functional group modifications to create derivatives 6 and 7 did not show additive free energy gains and STD NMR data point to small variations in mode of binding as a probable cause. Improved syntheses of disaccharides 2-7 are reported.
Department of Radiology, Molecular Imaging Program at Stanford and Bio-X Program, School of Medicine, Stanford University, CA 94305, United States. Electronic address: linacui@stanford.edu.
Lina
L
Cui
Department of Chemistry, Alberta Glycomics Centre, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
Chang-Chun
CC
Ling
Department of Chemistry, Gunning-Lemieux Chemistry Centre, Alberta Glycomics Centre, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
Joanna
J
Sadowska
Department of Chemistry, Gunning-Lemieux Chemistry Centre, Alberta Glycomics Centre, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
David R
DR
Bundle
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001666:Binding Sites, Antibody; D004187:Disaccharides / Q000737:chemistry / Q000276:immunology*; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D013499:Surface Properties; D017160:Trichinella spiralis / Q000737:chemistry / Q000276:immunology*
D000911:Antibodies, Monoclonal; D004187:Disaccharides; D000939:Epitopes
1,2-cis-β Glycosidic linkages; Protein carbohydrate interaction; Saturation transfer difference (STD) NMR; Synthesis of cell surface N-glycan; Trichinella spirallis; Tyvelose