Conformation and Dynamics of an Fab'-Bound Peptide by Isotope-Edited NMR Spectroscopy Article

Tsang, P, Ranee, M, Fieser, TM et al. (1992). Conformation and Dynamics of an Fab'-Bound Peptide by Isotope-Edited NMR Spectroscopy . BIOCHEMISTRY, 31(15), 3862-3871. 10.1021/bi00130a018

cited authors

  • Tsang, P; Ranee, M; Fieser, TM; Ostresh, JM; Houghten, RA; Lerner, RA; Wright, PE

authors

abstract

  • The dynamics and conformation of the peptide antigen MHKDFLEKIGGL bound to the F'ab fragment of the monoclonal antipeptide antibody B13A2, raised against a peptide from myohemerythrin, have been investigated by isotope-edited NMR techniques. The peptides were labeled with 15N (98%) or 13C (99%) at the backbone of individual amino acid residues. Well-resolved amide proton and nitrogen backbone resonances were obtained and assigned for eight of the 12 residues of this bound peptide. Significant resonance line width and chemical shift differences were observed. The 15N and 1H line width variations are attributed to differential backbone mobilities among the bound peptide residues which are consistent with the previously mapped epitope of this peptide antigen. Local structural information was obtained from isotope-directed NOE studies. The approximate distances associated with the experimental NOEs were estimated on the basis of a theoretical NOE analysis involving the relative integrated intensities of the NOE and source peaks. In this way, the sequential NH-NH NOEs obtained for seven of the F'ab-bound peptide residues were shown to correspond to interproton separations of ˜3 Á or less. Such short distances indicate that the backbone dihedral angles of these residues are in the a rather than the β region of Φ, Ψ conformational space; the peptide most likely adopts a helical conformation from F5 to G11 within the antibody combining site. The significance of these results with respect to the type and extent of conformational information obtainable from studies of high molecular weight systems is discussed. © 1992, American Chemical Society. All rights reserved.

publication date

  • April 1, 1992

published in

Digital Object Identifier (DOI)

start page

  • 3862

end page

  • 3871

volume

  • 31

issue

  • 15