Dielectric dispersion of G-actin

Abstract

The dielectric dispersion of G-actin has been measured and the value of its dipole moment at neutral pH in a salt-free solution was estimated to be about 660 Debye. The dependence of the dielectric properties on protein concentration, pH and solvent viscosity, and the effect of urea denaturation were examined.

The results suggest that the main mechanism of dielectric relaxation is the orientation of the permanent dipole, while the proton fluctuation makes a considerable contribution to the dielectric increment.