Binding of modified fragments of the Shigella dysenteriae type 1 O-specific polysaccharide to monoclonal IgM 3707 E9 and docking of the immunodeterminant to its modeled Fv.
The O-specific polysaccharide (O-SP) of Shigella dysenteriae type 1 has been shown by others to have the structure-->3)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->2)-alp ha-D- Galp-(1-->3)-alpha-D-GlcpNAc-(1-->. We have shown in the past that IgM 3707 E9, an anti S. dysenteriae type 1 O-SP monoclonal antibody, binds specifically to the -alpha-L-Rhap-(1-->2)-alpha-D-Galp-determinant of the polysaccharide. In this report we show that determinant to have hydrogen bonds, necessary for binding to the antibody, involving positions 3, 4 and 6 of the galactopyranosyl residue. The hydroxyl groups of the rhamnopyranosyl moiety of the immunodeterminant appear not to partake in hydrogen-bond interactions with the antibody. A model is presented of the Fv of IgM 3707 E9 based on our previously established cDNA-sequence and two known, highly homologous immunoglobulin crystal structures. The methyl glycoside of the immunodeterminant alpha-L-rhamnopyranosyl-(1-->2)-alpha-D-galactopyranose is docked to the combining area of the Fv.
Miller
C E
CE
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Mulard
L A
LA
Padlan
E A
EA
Glaudemans
C P
CP
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D002240:Carbohydrate Sequence; D016056:Immunodominant Epitopes / Q000276:immunology*; D007128:Immunoglobulin Fragments / Q000378:metabolism*; D007075:Immunoglobulin M / Q000276:immunology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009010:Monte Carlo Method; D019081:O Antigens / Q000276:immunology*; D011485:Protein Binding; D012762:Shigella dysenteriae / Q000276:immunology*
D000911:Antibodies, Monoclonal; D016056:Immunodominant Epitopes; D007128:Immunoglobulin Fragments; D007075:Immunoglobulin M; D019081:O Antigens