Molecular dynamics calculations of partial molar volumes of amino acids in aqueous solutions

Partial molar volumes of amino acids in their zwitterionic and molecular forms were calculated using molecular dynamics simulations of these systems in aqueous solutions. Calculations performed with the TIP4P, SPC (rigid and flexible), SPC/E, and polarizable water models showed that the choice of water model can have a significant impact on the calculated volumes. The effect of treatment of long-range electrostatic interactions on the calculated results was also investigated. The volumes obtained in simulations with a properly chosen water model fit well the experimental data for both molecular and zwitterionic forms of amino acids.