Does water drive protein folding?

We investigate the thermodynamic stability of a protein in water using an all-atom molecular model. The free energy change upon protein folding is calculated using an approach that combines molecular dynamics simulations and the integral-equation theory of molecular liquids. With this computational approach, we can analyze components of free energy such as protein intramolecular energy, hydration energy, and hydration entropy. Based upon its free energy change during protein folding, we argue that water can thermodynamically contribute to the structural stability of a protein.