DIELECTRIC-RELAXATION, MOLECULAR-MOTION AND INTERPROTEIN INTERACTIONSIN MYOGLOBIN SOLUTION

The results of the investigation of protein molecule dynamic in soluti on by Time Domain Dielectric Spectroscopy are presented. The horse myo globin solutions in wide range of concentration from 0.6% to 54% at 20 degrees C have been investigated. The result of analysis produced in the term of dipole correlation function has shown that the obtained co rrelation function of macromolecule motion may be presented as sum of three components corresponding to three kinds of protein motions: anis otropic intramolecular motion, anisotropic Brownian tumbling and isotr opic slow motion. We suppose that the cause of protein tumbling anisot ropy and the possibility to keep slow motion is the interprotein elect rostatic interactions. The characteristic time of slow motion depends on the concentration of protein and perhaps is controlled by translati onal diffusion. The dipole moment of myoglobin calculated by the Onsag er-Oncley equation is 200D for solutions less than 10% protein concent ration. It is in a good agreement with the theoretical value.