Electrostatic solvation free energy of amino acid side chain analogs: Implications for the validity of electrostatic linear response in water

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Abstract

Electrostatic free energies of solvation for 15 neutral amino acid side chain analogs are computed. We compare three methods of varying computational complexity and accuracy for three force fields: free energy simulations, Poisson-Boltzmann (PB), and linear response approximation (LRA) using AMBER, CHARMM, and OPLS-AA force fields. We find that deviations from simulation start at low charges for solutes. The approximate PB and LRA produce an overestimation of electrostatic solvation free energies for most of molecules studied here. These deviations are remarkably systematic. The variations among force fields are almost as large as the variations found among methods. Our study confirms that success of the approximate methods for electrostatic solvation free energies comes from their ability to evaluate free energy differences accurately.

Original languageEnglish (US)
Pages (from-to)878-885
Number of pages8
JournalJournal of Computational Chemistry
Volume32
Issue number5
DOIs
StatePublished - Apr 15 2011
Externally publishedYes

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Keywords

  • Gibbs free energy
  • hydration
  • reversible work

ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Mathematics

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