Electrostatics of deformable lipid membranes

Igor Vorobyov, Borislava Bekker, Toby W. Allen

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

It was recently demonstrated that significant local deformations of biological membranes take place due to the fields of charged peptides and ions, challenging the standard model of membrane electrostatics. The ability of ions to retain their immediate hydration environment, combined with the lack of sensitivity of permeability to ion type or even ion pairs, led us to question the extent to which hydration energetics and electrostatics control membrane ion permeation. Using the arginine analog methyl-guanidinium as a test case, we find that although hydrocarbon electronic polarizability causes dramatic changes in ion solvation free energy, as well as a significant change (∼0.4 V) in the membrane dipole potential, little change in membrane permeation energetics occurs. We attribute this to compensation of solvation terms from polar and polarizable nonpolar components within the membrane, and explain why the dipole potential is not fully sensed in terms of the locally deformed bilayer interface. Our descriptions provide a deeper understanding of the translocation process and allow predictions for poly-ions, ion pairs, charged lipids, and lipid flip-flop. We also report simulations of large hydrophobic-ion-like membrane defects and the ionophore valinomycin, which exhibit little membrane deformation, as well as hydrophilic defects and the ion channel gramicidin A, to provide parallels to membranes deformed by unassisted ion permeation.

Original languageEnglish (US)
Pages (from-to)2904-2913
Number of pages10
JournalBiophysical Journal
Volume98
Issue number12
DOIs
StatePublished - Jun 16 2010

ASJC Scopus subject areas

  • Biophysics

Fingerprint Dive into the research topics of 'Electrostatics of deformable lipid membranes'. Together they form a unique fingerprint.

  • Cite this