Diphytanoyl lipids as model systems for studying membrane-active peptides
Sezgin Kara1, Sergii Afonin2, Oleg Babii3
1Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
Biochimica Et Biophysica Acta. Biomembranes
|June 8, 2017
Summary
Diphytanoyl lipids form stable bilayers only with choline headgroups (DPhPC), crucial for membrane studies. Branched lipids prevent peptide insertion, impacting electrophysiology and structural analysis.
Area of Science:
- Membrane biophysics
- Lipid-protein interactions
- Solid-state NMR
Background:
- Diphytanoyl lipids offer unique membrane properties like stability and low permeability.
- Synthetic diphytanoyl phospholipids serve as model membranes in electrophysiology.
- Suitability of these lipids for solid-state NMR requires investigation.
Purpose of the Study:
- To assess diphytanoyl lipids' suitability for solid-state NMR.
- To compare interactions of diphytanoyl lipids with a model peptide against straight-chain lipids.
- To investigate the structural behavior of the antimicrobial peptide PGLa in diphytanoyl lipid membranes.
Main Methods:
- 31P NMR to monitor lipid phase properties.
- 19F NMR and circular dichroism for peptide structural analysis.
- Experiments conducted on oriented membrane samples.
Main Results:
- Only diphytanoyl lipids with choline headgroups (DPhPC) formed stable bilayers; others formed non-lamellar structures.
- Temperature and hydration are critical for maintaining bilayer integrity.
- The peptide PGLa remained surface-bound to DPhPC bilayers, unlike in straight-chain membranes, due to lipid cohesivity and negative spontaneous curvature.
Conclusions:
- Diphytanoyl lipids, particularly DPhPC, can form stable bilayers suitable for certain biophysical studies.
- Careful control of experimental conditions (temperature, hydration) is essential.
- The unique properties of diphytanoyl lipids influence membrane-active peptide behavior, requiring consideration in electrophysiological and structural studies.
Keywords:
Antimicrobial peptide PGLaDiphytanoyl phospholipidsMembrane-active peptidesOriented circular dichroismPeptide-lipid interactionsSolid-state (31)P NMR and (19)F NMR spectroscopyMore Related Videos
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