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Title: Communication: Modeling charge-sign asymmetric solvation free energies with nonlinear boundary conditions

Abstract

We show that charge-sign-dependent asymmetric hydration can be modeled accurately using linear Poisson theory after replacing the standard electric-displacement boundary condition with a simple nonlinear boundary condition. Using a single multiplicative scaling factor to determine atomic radii from molecular dynamics Lennard-Jones parameters, the new model accurately reproduces MD free-energy calculations of hydration asymmetries for: (i) monatomic ions, (ii) titratable amino acids in both their protonated and unprotonated states, and (iii) the Mobley “bracelet” and “rod” test problems [D. L. Mobley, A. E. Barber II, C. J. Fennell, and K. A. Dill, “Charge asymmetries in hydration of polar solutes,” J. Phys. Chem. B 112, 2405–2414 (2008)]. Remarkably, the model also justifies the use of linear response expressions for charging free energies. Our boundary-element method implementation demonstrates the ease with which other continuum-electrostatic solvers can be extended to include asymmetry.

Authors:
 [1];  [2]
  1. Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)
  2. Computation Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
Publication Date:
OSTI Identifier:
22436530
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMINO ACIDS; ATOMIC RADII; BOUNDARY CONDITIONS; BOUNDARY ELEMENT METHOD; FREE ENERGY; HYDRATION; MOLECULAR DYNAMICS METHOD; SIMULATION

Citation Formats

Bardhan, Jaydeep P., and Knepley, Matthew G.. Communication: Modeling charge-sign asymmetric solvation free energies with nonlinear boundary conditions. United States: N. p., 2014. Web. doi:10.1063/1.4897324.
Bardhan, Jaydeep P., & Knepley, Matthew G.. Communication: Modeling charge-sign asymmetric solvation free energies with nonlinear boundary conditions. United States. doi:10.1063/1.4897324.
Bardhan, Jaydeep P., and Knepley, Matthew G.. Tue . "Communication: Modeling charge-sign asymmetric solvation free energies with nonlinear boundary conditions". United States. doi:10.1063/1.4897324.
@article{osti_22436530,
title = {Communication: Modeling charge-sign asymmetric solvation free energies with nonlinear boundary conditions},
author = {Bardhan, Jaydeep P. and Knepley, Matthew G.},
abstractNote = {We show that charge-sign-dependent asymmetric hydration can be modeled accurately using linear Poisson theory after replacing the standard electric-displacement boundary condition with a simple nonlinear boundary condition. Using a single multiplicative scaling factor to determine atomic radii from molecular dynamics Lennard-Jones parameters, the new model accurately reproduces MD free-energy calculations of hydration asymmetries for: (i) monatomic ions, (ii) titratable amino acids in both their protonated and unprotonated states, and (iii) the Mobley “bracelet” and “rod” test problems [D. L. Mobley, A. E. Barber II, C. J. Fennell, and K. A. Dill, “Charge asymmetries in hydration of polar solutes,” J. Phys. Chem. B 112, 2405–2414 (2008)]. Remarkably, the model also justifies the use of linear response expressions for charging free energies. Our boundary-element method implementation demonstrates the ease with which other continuum-electrostatic solvers can be extended to include asymmetry.},
doi = {10.1063/1.4897324},
journal = {Journal of Chemical Physics},
number = 13,
volume = 141,
place = {United States},
year = {Tue Oct 07 00:00:00 EDT 2014},
month = {Tue Oct 07 00:00:00 EDT 2014}
}
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