SECONDARY CHEMICAL-SHIFTS IN H-1-NMR SPECTRA OF NATIVE AND COMPACT DENATURED BINASE

X-Ray analysis was used to determine the secondary chemical shifts of 13 protons in the high-field region of the H-1 NMR spectra of native and compact denatured binase. Account was taken of the circular currents of the aromatic amino acids and, in some cases, electric fields and magnet anisotropy of the bonds. For native binase, the theoretical and experimental secondary chemical shifts were in agreement. To model the compact denatured state, the distances were isotropically increased, and the effect of the electric fields of the water molecules was allowed for. No secondary chemical shift was observed in the high-field region, presumably because water molecules enter the hydrophobic regions of the protein and interact with the aromatic rings.