title: Analysis of the binding site architecture of monoclonal antibodies to morphine by using competitive ligand binding and molecular modeling.
abstract: The structural features of mAb directed against the opiate morphine were analyzed by using competitive ligand analog-binding studies, examination of the V region amino acid sequence, and computer-aided molecular modeling of the fragment V region. The antibody response in BALB/c mice to morphine is relatively restricted, in that all of the mAb examined in this study contained the same lambda L chain and very similar H chain V regions. A three-dimensional model of the antimorphine-binding site was constructed by using computational and graphic display techniques. Each of the six complementary-determining regions was constructed by using fragment replacement methods employing canonical loop conformations of known "parent" structures. Experimental competitive ligand-binding data and theoretical modeling suggest that a charged glutamate residue at position H:50 and aromatic side chains of residues H:33W, H:47W, H:58F, H:95W, H:101iY, and L:91W are key features in ionic and hydrophobic interactions with the ligand. This study represents the first use of theoretical and experimental modeling techniques to describe the Ag-binding site of a mouse fragment V region containing a lambda L chain.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston 77030.
authors.forename: P H
authors.initials: PH
authors.lastname: Kussie
authors.forename: J M
authors.initials: JM
authors.lastname: Anchin
authors.forename: S
authors.initials: S
authors.lastname: Subramaniam
authors.forename: J A
authors.initials: JA
authors.lastname: Glasel
authors.forename: D S
authors.initials: DS
authors.lastname: Linthicum
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000235:genetics; D001483:Base Sequence; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D003201:Computers; D005260:Female; D007135:Immunoglobulin Variable Region / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009020:Morphine / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D007135:Immunoglobulin Variable Region; D009020:Morphine