Use of two-dimensional ¹H nuclear magnetic resonance to study high-affinity antibody-peptide interactions

In general, we can conclude that, while in some cases changes in the coupling constants within a given residue may contribute to the observed changes in the intensities of the COSY cross-peaks in the bound peptide spectrum, for many their absence from the spectrum will also reflect an increase in the linewidth of the corresponding resonances from which the peak derives. Moreover, since many peptides undergo rapid conformational averaging in solution,^53,54 changes in the J values are likely to correspond to the localization of the amino acid side chains in specific antibody: peptide interactions. From the analysis of the COSY spectrum of the bound peptide, as described above, we can therefore extract information pertaining both to the dynamic behavior of residues in the peptide when bound within the antibody combining site, and to the degree of interaction of individual residues in the peptide with those of the antibody in the bound complex.