Liquid-vapor interfacial properties of aqueous solutions of guanidinium and methyl guanidinium chloride: influence of molecular orientation on interface fluctuations.

ABSTRACT: The guanidinium cation (C(NH2)3(+)) is a highly stable cation in aqueous solution due to its efficient solvation by water molecules and resonance stabilization of the charge. Its salts increase the solubility of nonpolar molecules ("salting-in") and decrease the ordering of water. It is one of the strongest denaturants used in biophysical studies of protein folding. We investigate the behavior of guanidinium and its derivative, methyl guanidinium (an amino acid analogue) at the air-water surface, using atomistic molecular dynamics (MD) simulations and calculation of potentials of mean force. Methyl guanidinium cation is less excluded from the air-water surface than guanidinium cation, but both cations show orientational dependence of surface affinity. Parallel orientations of the guanidini

SUBMITTER: Ou S 

PROVIDER: S-EPMC4216681 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature