CALCULATION OF LOW-FIELD CHEMICAL-SHIFTS FOR ALPHA-CH PROTONS IN NATIVE AND COMPACT DENATURED BINASE

Crystallographic data on binase and models of internal electric and ma gnetic fields were used to calculate the chemical shift dispersion (CS D) for alpha-CH protons of residues in beta-regions. Fitting parameter s were found describing the internal fields of peptide groups and perm itting conciliation of the theoretical and experimental CSD for native protein. The same models were used to assess the behavior of proton C SD upon binase transition to a compact denatured state. it was shown t hat disappearance of low-field H-1 NMR lines of alpha-CH protons does not indicate disruption of-secondary-structure elements, but can be ex plained by fluctuations in the H-bond network caused by pronounced int ramolecular dynamics.