Water molecules and the hydrogen-bond network are essential structural components of many biological macromolecular systems, such as nucleic acids, as well as fibrillar and globular proteins. The water density in the protein hydration shell is known to differ from that of bulk water. In this paper, spatial density as function of the distance from the protein surface is discussed. The electric potential function is considered in the same way. The resulting profiles of the bound water density are characterized by the presence of several distinct maxima due to the existence of the regular structure of bound water at distances over 7 Å. The minor discrepancies that are observed in both radial functions for different proteins are explained by topological variations that were revealed earlier by studying the valence and dihedral angle-distribution functions for water bound to the same proteins.
$^1$Department of Physics, Moscow State University, Moscow, 119991 Russia
$^2$Specialized Educational Scientific Center, Moscow State University, Moscow, 121357 Russia