First-Principles Study of Hydrophobic Interaction

Hydrophobicity is the molecular driving force behind numerous important biological processes, including protein folding and the formation of biological membranes. A quantitative understanding of hydrophobic interactions is crucial for modeling protein structures and manipulation of hydrophobic nanoparticles/nanotubes in aqueous solutions.

As a model for hydrophobic association, we employed first-principles simulations to evaluate the force between two methanes dissolved in water. A constrained MD approach is developed to efficiently calculate the free energy during the association of the two methanes. One conclusion is that the strength and shape of the (hydrophobic) potential of mean force are in conflict with earlier classical-force-field simulations but agree well with solubility experiments. We also analyzed the dynamic behavior of water in the solvation shell and found well-structured solvation shells for particular methane-methane separations.

In view of deficiencies of the current classical water model, we will continue works on constructing new water potentials, aiming to better reproduce hydrophobic interactions in a molecular simulation. Hydrophobic and van der Waals interactions are the two molecular driving forces in almost all biological activities in a cell.