"Environmental dependence of the dynamics of protein hydration water"

J. Amer. Chem. Soc.,  October 1999, p. 9740-9741, Vol. 121, No. 41   (communication)
 
 

We report a molecular dynamics (MD) simulation study that addresses the question: does the picosecond dynamics of hydration water depend on the protein environment? We compare water mobility in a crystal, dry and hydrated powders, and a protein/water "cluster" model commonly employed in MD simulations. Our principal findings are: (1) the overall water mobility on the time scale of tens of picoseconds is essentially identical in the crystal and hydrated powders; (2) water mobility is significantly higher in a cluster compared to the crystal and powder at a given  hydration level. These results suggest that experiments performed on powder samples are appropriate for discussing water dynamics in native protein environments and that simulations of clusters do not give a quantitatively correct picture of water dynamics near protein surfaces.