Coupling between Inclusions and Membranes at the Nanoscale
Florent Bories1, Doru Constantin2, Paolo Galatola1
1Laboratoire "Matière et Systèmes Complexes" (MSC), UMR 7057 CNRS, Université Paris 7 Diderot, 75205 Paris Cedex 13, France.
Physical Review Letters
|April 26, 2018
Summary
The slope of lipid bilayers at the boundary of membrane proteins like ion channels was measured for the first time. This surprising steepness impacts protein activity and was confirmed across different membrane systems.
Area of Science:
- Membrane biophysics
- Structural biology
- Biomolecular dynamics
Background:
- Cell membrane inclusions, such as ion channels, are functionally modulated by their host lipid bilayer.
- This interaction involves elastic coupling, including hydrophobic matching and the bilayer's slope at the inclusion boundary.
- The bilayer slope parameter has remained unquantified until now.
Purpose of the Study:
- To measure the elusive slope of the lipid bilayer at the boundary of a membrane protein.
- To investigate the influence of this slope on protein-membrane interactions.
- To validate findings across diverse membrane environments.
Main Methods:
- Combined small-angle X-ray scattering (SAXS) data with a comprehensive elastic model.
- Quantified the bilayer slope for the gramicidin channel.
- Utilized conductivity measurements and compared with simulation literature for validation.
Main Results:
- Successfully measured the bilayer slope at the gramicidin channel boundary.
- Observed a surprisingly steep slope in two distinct membrane systems.
- Demonstrated that the slope is a significant factor regardless of membrane elastic properties.
Conclusions:
- The lipid bilayer slope at membrane inclusion boundaries is a measurable and significant parameter.
- This steep slope influences the elastic coupling between proteins and membranes.
- Findings provide new insights into membrane protein function and interactions.
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