Flexibility vs rigidity of amphipathic peptide conjugates when interacting with lipid bilayers
Oleg Babii1, Sergii Afonin2, Tim Schober1
1Karlsruhe Institute of Technology, Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
Biochimica Et Biophysica Acta. Biomembranes
|September 30, 2017
Summary
Photoisomerization of diarylethene moiety (DAET) in peptide conjugates revealed how molecular flexibility impacts peptide structure and behavior in lipid membranes. Rigid and flexible forms showed distinct structures in gel-phase lipid bilayers.
Area of Science:
- Biophysical Chemistry
- Supramolecular Chemistry
- Membrane Biophysics
Background:
- Peptide conjugates are valuable tools for studying biomolecular interactions.
- Understanding how molecular rigidity affects peptide behavior in lipid membranes is crucial.
- Diarylethene moiety (DAET) photoisomerization offers a light-controlled method to alter molecular conformation.
Purpose of the Study:
- To investigate the impact of molecular rigidity/flexibility on peptide structure and behavior within lipid membranes.
- To utilize the photoisomerization of a diarylethene moiety (DAET) within peptide conjugates as a probe.
- To synthesize and study β-strand-DAET-α-helix and α-helix-DAET-α-helix models in phospholipid membranes.
Main Methods:
- Synthesis of peptide conjugates incorporating a diarylethene moiety (DAET).
- Light-induced photoisomerization of DAET to generate rigid and flexible forms.
- Structural, orientational, and conformational analysis using circular dichroism and solid-state 19F-NMR spectroscopy.
- Differential scanning calorimetry to assess effects on lipid thermotropic phase transitions.
Main Results:
- Photoisomerization of DAET generated distinct rigid and flexible states of the peptide conjugates.
- Structural differences between rigid and flexible forms were observed only in anisotropic lipid environments and gel phases.
- Both conjugate models destabilized the lamellar gel phases of the lipid membranes.
- Conformational mobility of the peptide junction varied between the rigid and flexible states.
Conclusions:
- Molecular rigidity/flexibility significantly influences peptide conjugate structure and behavior within specific lipid membrane environments (anisotropic, gel phase).
- DAET photoisomerization is an effective tool for modulating peptide conjugate conformation and probing membrane interactions.
- The studied peptide conjugates exhibit membrane-destabilizing effects on lamellar gel phases.
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