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Realistic Membrane Modeling Using Complex Lipid Mixtures in Simulation Studies
Published on: September 1, 2023
CHARMM-GUI Membrane Builder for mixed bilayers and its application to yeast membranes
Sunhwan Jo1, Joseph B Lim, Jeffery B Klauda
1Department of Molecular Biosciences and Center for Bioinformatics, University of Kansas, Lawrence, Kansas 66047, USA.
Biophysical Journal
|July 8, 2009
Summary
CHARMM-GUI Membrane Builder now creates complex lipid bilayers. Unsaturated lipids significantly impact membrane properties like surface area and cholesterol orientation.
Area of Science:
- Biophysics
- Computational Chemistry
- Materials Science
Background:
- Accurate modeling of biological membranes is crucial for understanding cellular processes.
- Heterogeneous lipid bilayers with proteins present significant computational challenges.
Purpose of the Study:
- To enhance the CHARMM-GUI Membrane Builder for automated construction of complex lipid bilayers.
- To investigate the influence of lipid composition, particularly unsaturated chains, on membrane properties.
Main Methods:
- Utilized the expanded CHARMM-GUI Membrane Builder to create yeast-like lipid bilayers.
- Simulated four distinct membranes with varying cholesterol and phospholipid concentrations at 303.15 K for 170 ns.
- Analyzed membrane properties including lipid surface area, density profiles, deuterium order parameters, and cholesterol tilt angle.
Main Results:
- Unsaturated phospholipid chain concentration was the primary determinant of membrane properties.
- High unsaturated chain concentration (73%) led to increased lipid surface area and decreased deuterium order parameters.
- Cholesterol tilt angle and orientation distributions were significantly affected by lipid saturation levels, with unique parallel orientations observed in unsaturated membranes.
Conclusions:
- The enhanced CHARMM-GUI Membrane Builder effectively models complex heterogeneous lipid bilayers.
- Membrane properties are highly sensitive to the degree of lipid chain saturation.
- Simulations suggest that membranes with high saturated lipid content adopt a liquid-ordered state, consistent with experimental observations.
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