Ions are ubiquitous in nature and all charged biomolecules subsequently develop an ion atmosphere.
Unfortunately, our understanding of ion atmospheres at the atomic level is rather limited, and this severely
impacts our ability to determine and rationalize protein-protein and protein-DNA interactions, for example. Here,
we propose to use the Kirkwood-Buff theory of solutions, coupled with local electroneutrality constraints, to
generate an improved view of the ion atmosphere around a variety of biomolecules. The results generate exact
relationships between the distribution of anions and cations around charged biomolecules and provide a way to
separate the ion contributions to electroneutrality from those related to the preferential interaction of a salt for a
biomolecule. A series of theoretical and computer simulation studies are proposed to achieve the two major aims
of the project. Aim 1: To Develop an Improved Description of Ion Atmospheres in Biological Systems. Aim 2: To
Determine the Consequences of Local Electroneutrality Requirements. The results from these studies will
provide a new view of the structure and extent of ion atmospheres around any biomolecular ion and will improve
our interpretation of the results from several biophysical techniques, such as osmotic pressure and ion counting
studies. Subsequently, this will impact our understanding of a wide range of systems of importance for the study
of many health-related diseases.