BER Structural Biology and Imaging Resources
Synchrotron, Neutron, and Cryo-EM
U.S. Department of Energy | Office of Science | Office of Biological and Environmental Research

Peptide Induced Lateral Segregation of Lipids in a Biomembrane

February 5, 2019

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. Reprinted with permission from 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. Copyright 2019 American Chemical Society. Work was performed at the DOE BER-supported Bio-SANS instrument at HFIR and the BES-supported BASIS instrument at the 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

Reference
Peptide Induced Lateral Segregation of Lipids in a Biomembrane
Sharma V.K., Qian S., Langmuir, 35, 11, 4152-4160 (2019). DOI: 10.1021/acs.langmuir.8b04158