  We propose a dissipative electro-elastic network model (DENM) to describe the
dynamics and statistics of electrostatic fluctuations at active sites of
proteins. The model combines the harmonic network of residue beads with
overdamped dynamics of the normal modes of the network characterized by two
friction coefficients. The electrostatic component is introduced to the model
through atomic charges of the protein force field. The overall effect of the
electrostatic fluctuations of the network is recorded through the
frequency-dependent response functions of the electrostatic potential and
electric field at the active site. We also consider the dynamics of
displacements of individual residues in the network and the dynamics of
distances between pairs of residues. The model is tested against loss spectra
of residue displacements and the electrostatic potential and electric field at
the heme's iron from all-atom molecular dynamics simulations of three hydrated
globular proteins.
