(55f) Thermodynamic Properties of Aqueous Amino Acid Mixtures Using Coarse-Grained Molecular Dynamics Simulations

When modeling large systems with biomolecules, a coarse-grained force field is required to allow exploration of longer length and time scales. However, despite their prevalence in use for these systems, there has been limited exploration of how accurate these coarse-grained models are in reproducing the thermodynamic (and especially, thermal and energetic) properties of aqueous biological solutions. In this study, the coarse-grained MARTINI force field was used to capture structural, volumetric, and enthalpic properties of amino acids in liquid water. Specifically, we will present results from hybrid all-atom molecular dynamics (AAMD)/coarse-grained molecular dynamics (CGMD) simulations for aqueous amino acid systems. Within these simulations, we include amino acid ionization to zwitterions and the presence of hydronium ions, the later model built from the all-atom SCP/E water force field. Reported simulation properties include structural, volumetric, and energetic properties (such as heat capacities and heats of mixing) of the aqueous solutions at different temperatures and amino acid concentrations and compared against both exclusive AAMD simulations and experimental data.