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Title: Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles

Abstract

We measured the effect of intrinsic lipid curvature, J 0, on structural properties of asymmetric vesicles made of palmitoyl-oleoyl-phosphatidylethanolamine (POPE; J 0 < 0) and palmitoyl-oleoyl-phosphatidylcholine (POPC; J 0 ~ 0). Electron microscopy and dynamic light scattering were used to determine vesicle size and morphology, and x-ray and neutron scattering, combined with calorimetric experiments and solution NMR, yielded insights into leaflet-specific lipid packing and melting processes. Below the lipid melting temperature we observed strong interleaflet coupling in asymmetric vesicles with POPE inner bilayer leaflets and outer leaflets enriched in POPC. This lipid arrangement manifested itself by lipids melting cooperatively in both leaflets, and a rearrangement of lipid packing in both monolayers. On the other hand, no coupling was observed in vesicles with POPC inner bilayer leaflets and outer leaflets enriched in POPE. In this case, the leaflets melted independently and did not affect each other’s acyl chain packing. Furthermore, we found no evidence for transbilayer structural coupling above the melting temperature of either sample preparation. Our results are consistent with the energetically preferred location of POPE residing in the inner leaflet, where it also resides in natural membranes, most likely causing the coupling of both leaflets. The loss of thismore » coupling in the fluid bilayers is most likely the result of entropic contributions.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [3];  [1]
  1. Univ. of Graz (Austria). Inst. of Molecular Biosciences. Biophysics Division; BioTechMed-Graz (Austria)
  2. Univ. of Windsor, ON (Canada). Dept. of Chemistry and Biochemistry
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Shull Wollan Center. Biology and Soft Matter Division; Univ. of Tennessee, Knoxville, TN (United States). The Bredesen Center for Interdisciplinary Research and Graduate Education
  4. Graz Univ. of Technology (Austria). Inst. for Electron Microscopy and Nanoanalysis. Center for Electron Microscopy
  5. Univ. of Graz (Austria). Inst. of Molecular Biosciences; BioTechMed-Graz (Austria). Omics Center Graz
  6. Forschungszentrum Julich (Germany). Julich Centre for Neutron Science (JCNS). Inst. of Solid State Research
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Graz (Austria); Forschungszentrum Juelich (Germany)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Austrian Science Fund (FWF); Julich Centre for Neutron Science (JCNS) (Germany); European Union (EU)
OSTI Identifier:
1427601
Grant/Contract Number:
AC05-00OR22725; P27083-B20; N 283570
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Biophysical Journal
Additional Journal Information:
Journal Volume: 114; Journal Issue: 1; Journal ID: ISSN 0006-3495
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Eicher, Barbara, Marquardt, Drew, Heberle, Frederick A., Letofsky-Papst, Ilse, Rechberger, Gerald N., Appavou, Marie-Sousai, Katsaras, John, and Pabst, Georg. Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles. United States: N. p., 2018. Web. doi:10.1016/j.bpj.2017.11.009.
Eicher, Barbara, Marquardt, Drew, Heberle, Frederick A., Letofsky-Papst, Ilse, Rechberger, Gerald N., Appavou, Marie-Sousai, Katsaras, John, & Pabst, Georg. Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles. United States. doi:10.1016/j.bpj.2017.11.009.
Eicher, Barbara, Marquardt, Drew, Heberle, Frederick A., Letofsky-Papst, Ilse, Rechberger, Gerald N., Appavou, Marie-Sousai, Katsaras, John, and Pabst, Georg. Tue . "Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles". United States. doi:10.1016/j.bpj.2017.11.009. https://www.osti.gov/servlets/purl/1427601.
@article{osti_1427601,
title = {Intrinsic Curvature-Mediated Transbilayer Coupling in Asymmetric Lipid Vesicles},
author = {Eicher, Barbara and Marquardt, Drew and Heberle, Frederick A. and Letofsky-Papst, Ilse and Rechberger, Gerald N. and Appavou, Marie-Sousai and Katsaras, John and Pabst, Georg},
abstractNote = {We measured the effect of intrinsic lipid curvature, J0, on structural properties of asymmetric vesicles made of palmitoyl-oleoyl-phosphatidylethanolamine (POPE; J0 < 0) and palmitoyl-oleoyl-phosphatidylcholine (POPC; J0 ~ 0). Electron microscopy and dynamic light scattering were used to determine vesicle size and morphology, and x-ray and neutron scattering, combined with calorimetric experiments and solution NMR, yielded insights into leaflet-specific lipid packing and melting processes. Below the lipid melting temperature we observed strong interleaflet coupling in asymmetric vesicles with POPE inner bilayer leaflets and outer leaflets enriched in POPC. This lipid arrangement manifested itself by lipids melting cooperatively in both leaflets, and a rearrangement of lipid packing in both monolayers. On the other hand, no coupling was observed in vesicles with POPC inner bilayer leaflets and outer leaflets enriched in POPE. In this case, the leaflets melted independently and did not affect each other’s acyl chain packing. Furthermore, we found no evidence for transbilayer structural coupling above the melting temperature of either sample preparation. Our results are consistent with the energetically preferred location of POPE residing in the inner leaflet, where it also resides in natural membranes, most likely causing the coupling of both leaflets. The loss of this coupling in the fluid bilayers is most likely the result of entropic contributions.},
doi = {10.1016/j.bpj.2017.11.009},
journal = {Biophysical Journal},
number = 1,
volume = 114,
place = {United States},
year = {Tue Jan 09 00:00:00 EST 2018},
month = {Tue Jan 09 00:00:00 EST 2018}
}

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