Phase Separation in Atomistic Simulations of Model Membranes
Ruo-Xu Gu1, Svetlana Baoukina1, D Peter Tieleman1
1Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive, N.W. , Calgary , Alberta T2N 1N4 , Canada.
Journal of the American Chemical Society
|January 23, 2020
Summary
Atomistic simulations reveal how cholesterol influences lipid bilayer organization, leading to distinct liquid ordered and liquid disordered phases. This enhances understanding of complex plasma membrane lateral organization.
Area of Science:
- Biophysics
- Computational Biology
- Materials Science
Background:
- Plasma membrane lateral organization is crucial but not fully understood.
- Model lipid bilayers are used to study membrane domains.
- Atomistic simulations offer detailed insights but are computationally intensive.
Purpose of the Study:
- Investigate phase transitions and domain coexistence in binary (DPPC:DOPC) and ternary (DPPC:DOPC:cholesterol) lipid bilayers.
- Characterize the role of cholesterol in modulating membrane properties.
- Compare simulation results with experimental findings.
Main Methods:
- Atomistic molecular dynamics simulations.
- Simulations conducted at temperatures ranging from 310 K to 270 K.
- Analysis of lipid-lipid interactions and domain properties.
Main Results:
- Binary mixtures exhibit liquid-disordered (Ld) and coexistence of Ld with gel or ripple phases.
- Ternary mixtures show Ld and coexistence of liquid-ordered (Lo) with Ld or gel phases.
- Cholesterol incorporation leads to increased partitioning, smoothed phase transitions, and specific interaction geometries.
Conclusions:
- Domain coexistence significantly impacts bilayer properties.
- Cholesterol's interactions are key to its effect on phase behavior.
- Simulations provide valuable insights into lipid-lipid interactions and plasma membrane lateral organization.
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