It has been shown that in implicit solvent simulations that use PB forces employing a dielectric constant of 1.0 (as used in many force fields) the resulting MD trajectories do not always preserve native structures (using different protocols and programs). To reduce solvation forces, a common technique is to raise the dielectric constant . The dielectric constant for a protein has traditionally been estimated below, or at around 4 , but can also be significantly larger, as large as 10, in sites of catalytic importance . The optimal value differs between systems and are for example set to 4 or even to 17 . For implicit solvent simulations the proper dielectric constant of the solute is a controversial issue in the literature (see, e.g., ).