Proteins
fold and function in water, and protein–water interactions
play important roles in protein structure and function. In computational
studies on protein structure and interaction, the effect of water
is considered either implicitly or explicitly. Implicit water models
are frequently used in protein structure prediction and docking because
they are computationally much more efficient than explicit water models,
which are often employed in molecular dynamics (MD) simulations. However,
implicit water models that treat water as a continuous solvent medium
cannot account for specific atomistic protein–water interactions
that are critical for structure formation and interactions with other
molecules. Various methods for predicting water molecules that form
specific atomistic interactions with proteins have been developed.
Methods involving MD simulations or the integral equation theory tend
to produce more accurate results at a higher computational cost than
simple geometry- or energy-based methods. Here, we present a novel
method for predicting water positions on a protein surface called
GalaxyWater-wKGB, which is based on a statistical potential, a water
knowledge-based potential based on the generalized Born model (wKGB).
This method is accurate and rapid because it does not require conformational
sampling or iterative computation owing to the effective statistical
treatment employed to derive the potential. The statistical potential
describes specific protein atom–water interactions more accurately
than conventional potentials by considering the dependence on the
degree of solvent accessibility of protein atoms as well as on protein
atom–water distances and orientations. The introduction of
solvent accessibility allows effective consideration of competing
nonspecific protein–water and intraprotein interactions. When
tested on high-resolution protein crystal structures, this method
could recover similar or larger fractions of crystallographic water
180 times faster than the sophisticated integral equation theory,
3D-RISM. A web service of this water prediction method is freely available
at .