Amphipathic antimicrobial piscidin in magnetically aligned lipid bilayers
Anna A De Angelis1, Christopher V Grant, Matthew K Baxter
1Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California, USA.
Biophysical Journal
|September 6, 2011
Summary
Piscidin 1, an antimicrobial peptide, stabilizes anionic lipid bilayers, altering their structure and phase behavior. This study shows magnetically aligned bilayers are effective for studying such peptides.
Area of Science:
- Biophysics
- Structural Biology
- Biochemistry
Background:
- Antimicrobial peptides (AMPs) are crucial for innate immunity.
- Piscidin 1 is an amphipathic AMP with known membrane-disrupting activity.
- Understanding peptide-lipid interactions is key to antimicrobial drug development.
Purpose of the Study:
- To investigate the structural effects of piscidin 1 on phospholipid bilayers.
- To explore the utility of magnetically aligned bilayers for studying amphipathic peptides.
- To determine the orientation and dynamics of piscidin 1 within lipid bilayers.
Main Methods:
- Oriented-sample solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Utilized (31)P NMR and 2D separated-local-field experiments.
- Performed experiments across a temperature range (25 °C to 61 °C).
Main Results:
- Piscidin 1 significantly impacts anionic bilayers' phase behavior and structure, but not zwitterionic ones.
- The peptide stabilizes anionic bilayers, maintaining alignment at elevated temperatures.
- Determined piscidin 1's tilt angle to be 80 ± 5° and observed fast rotational diffusion.
Conclusions:
- Magnetically aligned phospholipid bilayers are suitable for structural studies of amphipathic peptides.
- Piscidin 1's interaction with anionic bilayers is specific and stabilizing.
- Solid-state NMR provides detailed structural insights into peptide-membrane interactions.
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