Nonintercalating Nanosubstrates Create Asymmetry between Bilayer Leaflets
| Autor: | Michael Teng, H. Larry Scott, Sameer Varma |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Surface Properties
Chemistry Bilayer Lipid Bilayers Charge density Lipid bilayer fusion Surfaces and Interfaces Lipid bilayer mechanics Molecular Dynamics Simulation Model lipid bilayer Condensed Matter Physics Article Nanostructures Crystallography Membrane Chemical physics Phosphatidylcholines Electrochemistry lipids (amino acids peptides and proteins) General Materials Science Adsorption Lipid bilayer phase behavior Lipid bilayer Spectroscopy |
| Zdroj: | Langmuir. 28:2842-2848 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | The physical properties of lipid bilayers can be remodeled by a variety of environmental factors. Here we investigate using molecular dynamics simulations the specific effects of nanoscopic substrates or external contact points on lipid membranes. We expose palmitoyl-oleoyl phosphatidylcholine bilayers unilaterally and separately to various model nano-sized substrates differing in surface hydroxyl densities. We find that a surface hydroxyl density as low as 10% is sufficient to keep the bilayer juxtaposed to the substrate. The bilayer interacts with the substrate indirectly through multiple layers of water molecules, however, despite such buffered interaction, the bilayers exhibit certain properties different from unsupported bilayers. The substrates modify transverse lipid fluctuations, charge density profiles and lipid diffusion rates, although differently in the two leaflets, which creates an asymmetry between bilayer leaflets. Other properties that include lipid cross-sectional areas, component volumes and order parameters are minimally affected. The extent of asymmetry that we observe between bilayer leaflets is well beyond what has been reported for bilayers adsorbed on infinite solid supports. This is perhaps because the bilayers are much closer to our nano-sized finite supports than to infinite solid supports, resulting in a stronger support-bilayer electrostatic coupling. The exposure of membranes to nanoscopic contact points, therefore, cannot be considered as a simple linear interpolation between unsupported membranes and membranes supported on infinite supports. In the biological context, this suggests that the exposure of membranes to non-intercalating proteins, such as those belonging to the cytoskeleton, should not always be considered as passive non-consequential interactions. |
| Databáze: | OpenAIRE |
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