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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Structure and phase behavior of archaeal lipid monolayers
Christoph Jeworrek1, Florian Evers, Mirko Erlkamp
1Physical Chemistry I, Faculty of Chemistry, TU Dortmund University, Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 14, 2011
Summary
Archaeal lipid monolayers form a U-shaped structure at interfaces. Their thickness and crystallinity depend on temperature and pressure, with gramicidin causing local disorder.
Area of Science:
- Biophysics
- Materials Science
- Archaeal Biology
Background:
- Archaeal lipids, like bipolar tetraethers, form unique membrane structures.
- Understanding lipid monolayer properties is crucial for biomimetic studies.
- Sulfolobus acidocaldarius lipids offer insights into extremophile adaptation.
Purpose of the Study:
- Investigate the structural and packing properties of archaeal lipid monolayers.
- Examine the influence of growth temperature, film pressure, and pH on monolayer organization.
- Determine the interaction of archaeal lipid monolayers with gramicidin.
Main Methods:
- X-ray reflectivity (XRR) and grazing incidence X-ray diffraction (GIXD) were employed.
- Langmuir films of polar lipid fraction E (PLFE) from Sulfolobus acidocaldarius were analyzed.
- Experiments were conducted across various temperatures, pH values, and surface pressures.
Main Results:
- A consistent monolayer thickness of ~30 Å suggests a U-shaped molecular conformation.
- Monolayer thickness increased with film pressure and decreased with temperature.
- Crystallinity was observed at lower temperatures (10-20 °C) but diminished at higher temperatures.
- Lipids from higher growth temperatures exhibited more rigid dibiphytanyl chains.
- Gramicidin induced disorder in the monolayer, primarily residing in disordered regions.
Conclusions:
- Archaeal bipolar tetraether lipids form stable monolayers with temperature- and pressure-dependent structures.
- Molecular conformation and domain crystallinity are sensitive to environmental conditions.
- Gramicidin perturbs the lipid monolayer locally, indicating specific interactions within disordered membrane areas.
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