title: Does a peptide bound to a monoclonal antibody always adopt a unique conformation?
abstract: The conformation of a synthetic undecapeptide derived from the Escherichia coli tryptophan synthase beta2 subunit was studied by NMR spectroscopy when bound to a monoclonal antibody (mAb 164-2) Fab' fragment directed against the native protein. The peptide 1(H-G-R-V-G-I-Y-F-G-M-K)11, peptide 11, was recognized by the antibody and its corresponding Fab' fragments with high affinity (K(D) = 1.1+/-0.2* 10(-8) M). Peptide 11 was labelled with 15N and its structure at the binding site of the Fab' 164-2 fragment was studied by isotope-editing techniques. 1H-15N heteronuclear spectra indicated the presence of two Fab'-peptide 11 complexes with two different conformations in slow chemical exchange on the chemical shift time scale.
authors.affiliation: Laboratoire de Résonance magnétique nucléaire, Institut Pasteur, Paris, France.
authors.forename: J I
authors.initials: JI
authors.lastname: Guijarro
authors.forename: L
authors.initials: L
authors.lastname: Djavadi-Ohaniance
authors.forename: F
authors.initials: F
authors.lastname: Baleux
authors.forename: M
authors.initials: M
authors.lastname: Delepierre
authors.forename: M E
authors.initials: ME
authors.lastname: Goldberg
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000936:Antigen-Antibody Complex; D004926:Escherichia coli / Q000737:chemistry; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000276:immunology; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D010455:Peptides / Q000276:immunology*; D011487:Protein Conformation; D014367:Tryptophan Synthase / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D007140:Immunoglobulin Fab Fragments; D010455:Peptides; D014367:Tryptophan Synthase