Solvent effects and hydration of a tripeptide in sodium halide aqueous solutions: an in silico study

In this work we are trying to gain insight into the mechanisms of ion-protein interactions in aqueous media at the molecular scale through fully atomistic molecular dynamics simulations. We present a systematic molecular simulation study of interactions of sodium and halide ions with a trialanine peptide in aqueous sodium halide solutions with different salts concentrations ( 0.20, 0.50, 1.0 and 2.0 M). Each simulation covers more than fifty nanoseconds to ensure the convergence of the results and to enable a proper determination of the tripeptide-ion interactions through the potentials of mean force. Changes in ion densities in the vicinity of different peptide groups are analysed and implications for the tripeptide conformations are discussed.