Spatial Dependence of Protein-Water Collective Hydrogen-Bond Dynamics

Using molecular dynamics simulations, we analyze collective vibrations in the hydration water of a small globular protein. We develop tools that allow spatial resolution of correlated protein and water motion, and use them to reveal correlated vibrations that extend up to 10 angstrom from the protein surface at far-infrared/THz frequencies that are sensitive to the chemical properties of the protein surface. Our results provide the first detailed description of long-range effects on protein hydration water dynamics and highlight the differences between single particle and collective dynamics, which are relevant in interpreting experimental observations.