Structural-Dynamic Behavior of Histamine in Solution: the Role of Water Models

A highly dilute aqueous solution of histamine at T = 300 K was studied by molecular dynamics using the TIP3P and SPC/E water models. It was shown that the local structure of the solution around histamine is determined by local Coulomb interactions and hydrogen bonds and is practically independent of the choice of the water model. Dynamic analysis based on the mean square displacement functions revealed a significant dependence of the diffusion behavior of histamine on the water model. It was found that the TIP3P water model leads to overestimated values of the diffusion coefficients of water and histamine and a transition to diffusive motion. It was found that the SPC/E water model provides slower dynamics of the solution components, and the values of the diffusion coefficients are in better agreement with experimental data. It was shown that the dynamics of histamine is highly sensitive to the choice of the water model, and the SPC/E model is more suitable for the correct description of the dynamic properties of the "histamine-water" system under physiological conditions.