Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.



Saddle-curvature instability of lipid bilayer induced by amphipathic peptides: a molecular model

Author affiliations

Abstract

Amphipathic peptides that partition into lipid bilayers affect the curvature elastic properties of their host. Some of these peptides are able to shift the Gaussian modulus to positive values, thus triggering an instability with respect to the formation of saddle curvatures. To characterize the generic aspects of the underlying mechanism, we employ a molecular lipid model that accounts for the interfacial tension between the polar and apolar regions of the membrane, for interactions between the lipid headgroups, and for the energy to stretch or compress the hydrocarbon chains. Peptides are modeled as cylinders that partition into the host membrane in a parallel orientation where they diminish the space available to the lipid headgroups and chains. The penetration depth into the membrane is determined by the angular size of the peptide's hydrophilic region. We demonstrate that only peptides with a small angular size of their hydrophilic region have an intrinsic tendency to render the Gaussian modulus more positive, and we identify conditions at which the Gaussian modulus adopts a positive sign upon increasing the peptide concentration. Our model allows us to also incorporate electrostatic interactions between cationic peptides and anionic lipids on the level of the linear Debye–Hückel model. We show that electrostatic interactions tend to shift the Gaussian modulus toward more positive values. Steric and electrostatic lipid–peptide interactions jointly decrease the effective interaction strength in the headgroup region of the host membrane thus suggesting a generic mechanisms of how certain amphipathic peptides are able to induce the formation of saddle curvatures.

Graphical abstract: Saddle-curvature instability of lipid bilayer induced by amphipathic peptides: a molecular model

Back to tab navigation

Article information


Submitted
21 Mar 2020
Accepted
06 May 2020
First published
06 May 2020

Soft Matter, 2020, Advance Article
Article type
Paper

Saddle-curvature instability of lipid bilayer induced by amphipathic peptides: a molecular model

R. Downing, G. Volpe Bossa and S. May, Soft Matter, 2020, Advance Article , DOI: 10.1039/D0SM00499E

Social activity

Search articles by author

Spotlight

Advertisements