Hydrogen-Bond Kinetics in the Solvation Shell of a Polypeptide

Analysis of a series of molecular dynamics simulations reveals that the kinetics of breaking and forming water−water hydrogen bonds is slower in the first solvation shell of a 16-residue polypeptide than in bulk water. The correlation time of hydrogen bonds persists significantly longer near hydrophobic groups than in bulk water. Hydrogen bonds are found to be stronger in the solvation shell of nonpolar groups. We show that the difference in hydrogen-bond kinetics in the different environments can be understood in terms of the energetics and the concerted forming and breaking of hydrogen bonds.