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Gramicidin A in Asymmetric Lipid Membranes

Oleg V Kondrashov1, Sergey A Akimov1

  • 1Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia.

Biomolecules
|January 8, 2025
PubMed

Insights

Gramicidin A channel formation is significantly influenced by lipid membrane asymmetry. This asymmetry increases the gramicidin A channel

Area of Science:

  • Biophysics
  • Membrane Biology
  • Computational Biology

Background:

  • Gramicidin A is a natural antimicrobial peptide forming cation-selective ion channels.
  • Channel function is defined by conducting state lifetime and monomer-dimer equilibrium.
  • Dimerization induces membrane deformations.

Purpose of the Study:

  • To investigate the impact of lipid membrane asymmetry on gramicidin A channel formation.
  • To quantify how spontaneous curvature and lateral tension asymmetry affect channel properties.

Main Methods:

  • Theoretical modeling of gramicidin A channel formation in asymmetric lipid monolayers.
  • Calculation of channel lifetime and dimerization/dissociation equilibrium constants under asymmetric conditions.

Main Results:

  • Lipid monolayer asymmetry, particularly spontaneous curvature and lateral tension, influences gramicidin A channel lifetime.
  • Asymmetry is predicted to significantly increase the average lifetime and equilibrium constant of gramicidin A dimerization.
  • These effects are relevant to plasma membranes of mammalian cells exposed to gramicidin A.

Conclusions:

  • Membrane asymmetry plays a crucial role in modulating gramicidin A ion channel function.
  • The findings provide insights into gramicidin A's behavior in complex biological membranes.
  • The study highlights the importance of considering membrane properties in peptide channel research.

Keywords:
asymmetric lipid membranechannel lifetimeequilibrium constantgramicidin Aintrinsic curvaturelateral tensionlipid–protein interactionmembrane biophysicstheory of elasticity

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