(76c) Hydrophobic and hydrophilic hydration and interactions relevant to biological systems

Water plays a critical role in mediating many complex self-assembly phenomena in aqueous solutions, including protein folding, micelle and membrane formation, and molecular recognition. Specifically through its structuring around various solution species, water can induce attractive or repulsive interactions between them, depending on their chemistry (hydrophobic vs hydrophilic), shape, and size. Molecular-level understanding of such solvation phenomena requires approaches that treat water explicitly and not simply as a dielectric continuum. I will present theoretical and simulation results on the lengthscale dependence of hydrophobic interactions, and highlight their relevance to condensed matter physics and to biological self-assembly. Knowledge of water-mediated interactions obtained over a broad thermodynamic space of temperature, pressure, and additive concentration can be integrated to understand a variety of biophysical phenomena. I will illustrate this point using an application to pressure denaturation of proteins.