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 i n a variety of aqueous solutions of the alkalihalide ions are studied by me ans of the reference interaction site model (RISM) theory. The order of sal t effect on the peptide stability is consistent with the experimental resul ts; the order follows the Hofmeister series. The results are further analyz ed in order to clarify the nature of the salt effect which determines the H ofmeister series and to find the reason why the Hofmeister series applies s o generally to a variety of solutes in aqueous solutions, ii heuristic mode l for explaining salt effects on the solvation structure of the peptide is proposed based on changes in the peptide-water pair correlation functions d ue to the ion perturbation.