Structural transitions in ion coordination driven by changes in competition for ligand binding.

ABSTRACT: Transferring Na(+) and K(+) ions from their preferred coordination states in water to states having different coordination numbers incurs a free energy cost. In several examples in nature, however, these ions readily partition from aqueous-phase coordination states into spatial regions having much higher coordination numbers. Here we utilize statistical theory of solutions, quantum chemical simulations, classical mechanics simulations, and structural informatics to understand this aspect of ion partitioning. Our studies lead to the identification of a specific role of the solvation environment in driving transitions in ion coordination structures. Although ion solvation in liquid media is an exergonic reaction overall, we find it is also associated with considerable free energy penalties f

SUBMITTER: Varma S 

PROVIDER: S-EPMC2735796 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature