Densities of the Standard Amino Acids in Aqueous Solutions via Molecular Dynamics Simulations

Abstract

The properties of amino acid aqueous solutions are crucial to the description of biological systems. Nevertheless, data on amino acid properties in the open literature are scattered and incomplete. Here, Molecular Dynamics simulations were applied to calculate the solution density of the standard amino acids over a range of compositions. Simulations were performed at constant room conditions (25 °C and 1 bar) using OPLS-AA/L, GROMOS 54A7, and CHARMM27 force fields to describe the amino acids. All force fields provided good agreement with the experimental data that were available in the literature. In addition, correlations between solution density and amino acid molality and concentration were presented. Further comparison between the force fields in terms of density increments has shown that GROMOS 54A7 provided a better representation of amino acids interactions and more accurate results.