Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 62: Charged Soft Matter, Polyelectrolytes and Ionic Liquids III
CPP 62.4: Vortrag
Donnerstag, 15. März 2018, 10:15–10:30, C 243
Force fields for monovalent and divalent metal cations in TIP3P water based on thermodynamic and kinetic properties — •Nadine Schwierz1 and Shavkat Mamatkulov2 — 1Max Planck Institut für Biophysik, Frankfurt, Germany — 2The Centre of Higher Technologies, Tashkent, Uzbekistan
Metal cations are essential in many vital processes. In order to capture the role of different cations in all-atom molecular dynamics simulations of biological processes, an accurate parametrization is crucial. Here, we develop force field parameters for the metal cations Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, and Ba2+ in combination with the TIP3P water model that is frequently used in biomolecular simulations. In progressing toward improved force fields, the approach presented here is an extension of previous efforts and allows us simultaneously reproduce thermodynamic and kinetic properties of aqueous solutions. We systematically derive the parameters of the 12-6 Lennard-Jones potential which accurately reproduce the experimental solvation free energy, the activity derivative, and the characteristics of water exchange from the first hydration shell of the metal cations. In order to reproduce all experimental properties, a modification of the Lorentz- Berthelot combination rule is required for Mg2+. Using a balanced set of solution properties, the optimized force field parameters aim to capture the fine differences between distinct metal cations including specific ion binding affinities and the kinetics of cation binding to biologically important anionic groups.