Dielectric properties of proteins : microscopic and macroscopic theory

A microscopic description of protein dielectric properties [1,2] is directly compared to a simpler, standard, continuum model [4], using cytochrome c as a model system. Relaxation free energies in response to a perturbing point test charge are compared, as well as the reorganization free energy for electron transfer between two cytochromes. The models agree regarding the mean properties of the system, but the continuum model underestimates the spatial variations of the local susceptibility, and greatly overestimates the reorganization free energy for electron transfer