The electrostatics of solvent and membrane interfaces and the role of electronic polarizability

Igor Vorobyov, Toby W. Allen

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

The electrostatics of solvent and lipid bilayer interfaces are investigated with the aim of understanding the interaction of ions and charged peptides with biological membranes. We overcome the lacking dielectric response of hydrocarbon by carrying out atomistic molecular dynamics simulations using a polarizable model. For air-solvent or solvent-solvent interfaces, the effect of polarizability itself is small, yet changes in the fixed atomic charge distribution are responsible for substantial changes in the potential. However, when electrostatics is probed by finite solutes, a cancellation of dominant quadrupolar terms from the macroscopic and microscopic (solute-solvent) interfaces eliminates this dependence and leads to small net contributions to partitioning thermodynamics. In contrast, the membrane dipole potential exhibits considerable dependence on lipid electronic polarizability, due to its dominant dipolar contribution. We report the dipole potential for a polarizable lipid hydrocarbon membrane model of 480-610 mV, in better accord with experimental measurements.

Original languageEnglish (US)
Article number185101
JournalJournal of Chemical Physics
Volume132
Issue number18
DOIs
StatePublished - May 31 2010

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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