Stability of Positively Charged Solutes in Water: A Transition from Hydrophobic to Hydrophilic.
To improve the description of solvation thermodynamics of biomolecules, we report here the dependence of solvation on the curvature and surface charge of positively charged solutes in water based on extensive molecular dynamics simulations analyzed using the two-phase thermodynamic method. At a surface charge of +0.4e, the compensating forces of favorable electrostatic stabilization and entropic destabilization cancel almost exactly, representing a molecular crossover point from hydrophobic to hydrophilic behavior, independent of curvature. These results suggest that one should include charge-dependent entropic corrections to continuum models aimed at predicting the solvation free energies of large biomolecules.
†Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology, Daejeon, Korea.|‡Materials and Simulation Process Center, California Institute of Technology, Pasadena, California 91125, United States.
Tod A
TA
Pascal
§Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
Shiang-Tai
ST
Lin
†Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology, Daejeon, Korea.|‡Materials and Simulation Process Center, California Institute of Technology, Pasadena, California 91125, United States.
William
W
Goddard
†Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology, Daejeon, Korea.
Yousung
Y
Jung
electrostatics; free-energy simulations; interfacial effects; molecular dynamics; surface tension