ANALYSIS OF THE LINE SHOPE IN H-1-NMR SPECTRUM OF CARBOANHYDRASE-B IN THE MOLTEN GLOBULE STATE .2. LINE-SHAPES COMPUTED AS SUPERPOSITION OF MULTIPLE SIGNALS

The nuclear Overhauser effects have been measured for protons of carboanhydrase B in the state of molten globule in the case of saturated line of the main methyl proton pool. The result for alpha-CH protons of residues involved in beta-sheets in the native protein is presented here. The experimental line shapes (the broad line of alpha-CH protons and the expanded high field wing of the methyl protons line) are described by the equation obtained for a line produced by superposition of many signals of the Lorenzian shapes, distributed continuously in a wide range of frequencies with amplitudes proportional to the resonance frequencies. The obtained broad distributions of secondary chemical shifts are considered to the result of existence of the same set of microstructures both in the native state and in the melted state of the protein. Only populations of structures arizing due to the high amplitude internal motion increase significantly in the molten globule.