Salt effect on stability and solvation structure of peptide: An integral equation study

Salt effects on the stability and on the solvation structure of a peptide in a variety of aqueous solutions of the alkalihalide ions are studied by means of the reference interaction site model (RISM) theory. The order of salt effect on the peptide stability is consistent with the experimental results; the order follows the Hofmeister series. The results are further analyzed in order to clarify the nature of the salt effect which determines the Hofmeister series and to find the reason why the Hofmeister series applies so generally to a variety of solutes in aqueous solutions, ii heuristic model for explaining salt effects on the solvation structure of the peptide is proposed based on changes in the peptide-water pair correlation functions due to the ion perturbation.