Peptide Induced Lateral Segregation of Lipids in a Biomembrane

02/05/2019

Aurein induces significant lateral segregation

Aurein induces significant lateral segregation in an initially uniform lipid bilayer composed of zwitterionic lipid and anionic lipid. QENS showed lipid lateral motion in the fluid phase was reduced even at low aurein concentrations, providing a cause for the heterogeneity. [Reprinted with permission from V.K. Sharma and S. Qian. 2019. Copyright 2019 American Chemical Society.]

Scientific Achievement

Small-angle neutron scattering (SANS) with contrast matching showed that the short anti-microbial peptide (AMP), Aurein 1.2, induced lateral segregation of lipids in a biomembrane at concentrations that are toxic to bacteria.

Aurein induces significant lateral segregation in an initially uniform lipid bilayer composed of zwitterionic lipid and anionic lipid. QENS showed lipid lateral motion in the fluid phase was reducedeven at low aurein concentrations, providing a cause for the heterogeneity. Work was performed at the DOE BER-supported Bio-SANS instrument at HFIR and the BES-supported BASIS instrument at SNS.

Significance and Impact

This study shows, for the first time, that AMPs can disrupt membrane function by inducing lateral segregation of lipids in the bilayer. Previously, AMPs were generally thought to disrupt membranes by forming transmembrane pores. This study provides fundamental insights into AMP-membrane interactions and new mechanistic insights into their mode-of-action.

Research Details

  • SANS was used to identify lateral lipid domains in liposomes in the presence of Aurein 1.2, a short 13 amino acid peptide.
  • Quasi-elastic neutron scattering (QENS) showed a decrease in lipid lateral motions in the presence of Aurein.

References

Sharma V.K., and S. Qian. 2019. “Effect of an Antimicrobial Peptide on Lateral Segregation of Lipids, a Structure and Dynamics Study by Neutron Scattering,” Langmuir 35(11), 4152-4160. [https://doi.org/10.1021/acs.langmuir.8b04158]