Distances of tyrosine residues from a spin-label hapten in the combining site of a specific monoclonal antibody

Publisher Website
Google Scholar
Abstract
The NMR spectra of an Fab fragment of a monoclonal antibody specifically directed against a nitroxide spin-label hapten were recorded at different concentrations of the hapten. The hybridoma producing this antibody was grown on deuterated phenylalanine, tryptophan and 3,5-dideuteriotyrosine or 2,6-dideuteriotyrosine. Difference spectra, without hapten minus with hapten, were calculated for each concentration of hapten. The difference spectra reveal 5 well-resolved singlet proton resonance signals from tyrosine deuterated in the 3,5-positions (H 2,6 Tyr) and 9 from tyrosine deuterated in the 2,6-positions (H 3,5 Tyr). The measured intensities of these signals as a function of combining site occupation were interpreted in terms of a theory involving intrinsic line widths (T2), the hapten off-rate (k) and distances to the paramagnetic center. Good agreement with theory is found for all of the isolated proton signals. The best estimate of k is 350 s-1; distances in the range 132 to < 9 .ANG. are calculated. Extension of this analysis to other amino acids is discussed.

This publication has 0 references indexed in Scilit: