Ion-Induced Transient Potential Fluctuations Facilitate Pore Formation and Cation Transport through Lipid Membranes

Unassisted ion transport through lipid membranes plays a crucial role in many cell functions without which life would not be possible, yet the precise mechanism behind the process remains unknown due to its molecular complexity. Here, we demonstrate a direct link between membrane potential fluctuati...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2022-12, Vol.144 (51), p.23352-23357
Main Authors: Roesel, David, Eremchev, Maksim, Poojari, Chetan S., Hub, Jochen S., Roke, Sylvie
Format: Article
Language:English
Subjects:
Cations
Ion Transport
Lipid Bilayers - metabolism
Membrane Potentials
Molecular Dynamics Simulation
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Summary:Unassisted ion transport through lipid membranes plays a crucial role in many cell functions without which life would not be possible, yet the precise mechanism behind the process remains unknown due to its molecular complexity. Here, we demonstrate a direct link between membrane potential fluctuations and divalent ion transport. High-throughput wide-field non-resonant second harmonic (SH) microscopy of membrane water shows that membrane potential fluctuations are universally found in lipid bilayer systems. Molecular dynamics simulations reveal that such variations in membrane potential reduce the free energy cost of transient pore formation and increase the ion flux across an open pore. These transient pores can act as conduits for ion transport, which we SH image for a series of divalent cations (Cu2+, Ca2+, Ba2+, Mg2+) passing through giant unilamellar vesicle (GUV) membranes. Combining the experimental and computational results, we show that permeation through pores formed via an ion-induced electrostatic field is a viable mechanism for unassisted ion transport.
ISSN:0002-7863
1520-5126
1520-5126
DOI:10.1021/jacs.2c08543