Figure 6.

Hydration sites identified in the active site of HIV protease (left) and pcDHFR (right). Hydration sites that contribute both entropically and enthalpically when replaced by ligands are shown in blue. The hydration sites whose entropic gain surpasses the enthalpic loss when replaced by ligands are shown in purple. The hydration sites whose enthalpic loss is larger than the entropic gain when replaced by ligands are shown in orange. Some of the interactions between specific hydration sites and protein residues that are discussed in the text are shown as red dashed lines.