The electrostatics of solvent and membrane interfaces and the role of electronic polarizability
Year: 2010
Type: article
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.
Source: The Journal of Chemical Physics
DOI: 10.1063/1.3402125
Authors: Igor Vorobyov, Toby W. Allen
Institution: University of California, Davis
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W1995229360