An extended dynamical hydration shell around proteins

The focus in protein folding has been very much on the protein backbone and sidechains. However, hydration waters make comparable contributions to the structure and energy of proteins. The coupling between fast hydration dynamics and protein dynamics is considered to play an important role in protein folding. Fundamental questions of protein hydration include, how far out into the solvent does the influence of the biomolecule reach, how is the water affected, and how are the properties of the hydration water influenced by the separation between protein molecules in solution? We show here that Terahertz spectroscopy directly probes such solvation dynamics around proteins, and determines the width of the…