Conformational changes induced by hapten in murine monoclonal antibodies to dinitrophenyl groups--the analysis by temperature-perturbation spectroscopy.

Two samples of murine monoclonal antibodies to dinitrophenyl groups were studied by difference thermal perturbation spectroscopy with particular attention to changes in the amount of perturbed chromophores induced in antibodies as a result of hapten binding (epsilon-2,4-dinitrophenyl-L-lysine). Despite the fact that both antibody samples belong to immunoglobulin G1 and have the same type of light chain, kappa, they were found to differ significantly in the number of the chromophores perturbed by temperature. The binding of hapten decreases the perturbation of chromophores only in the sample with the less rigid structure, as regards thermal perturbation. These data provide evidence that differences in the rigidity of the structure of variable domains affect the extent of conformational changes induced in the antibodies due to the interaction with an antigen.