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Binding of pediocin PA-1 with anionic lipid induces model membrane destabilization
Hélène Gaussier1, Thierry Lefèvre, Muriel Subirade
1Centre de recherche en Sciences et Technologie du Lait (STELA), and Institut sur les nutraceutiques et aliments fonctionnels (INAF), Département des sciences des aliments et de nutrition, Université Laval, Pavillon Paul-Comtois, Sainte-Foy, Québec, Canada.
Abstract:
To obtain molecular insights into the action mode of antimicrobial activity of pediocin PA-1, the interactions between this bacteriocin and dimyristoylphosphatidylcholine (DMPC) or dimyristoylphosphatidylglycerol (DMPG) model membranes have been investigated in D(2)O at pD 6 by Fourier transform infrared spectroscopy. The interactions were monitored with respect to alteration of the secondary structure of pediocin, as registered by the amide I' band, and phospholipid conformation, as revealed by the methylene nu(s)(CH(2)) and carbonyl nu(C;O) stretching vibrations. The results show that no interaction between pediocin and DMPC occurs. By contrast, pediocin undergoes a structural reorganization in the presence of DMPG. Upon heating, pediocin self-aggregates, which is not observed for this pD in aqueous solution. The gel-to-crystalline phase transition of DMPG shifts to higher temperatures with a concomitant dehydration of the interfacial region. Our results indicate that pediocin is an extrinsic peptide and that its action mechanism may lie in a destabilization of the cell membrane.
Insights
Pediocin PA-1 interacts with dimyristoylphosphatidylglycerol (DMPG) membranes, causing structural changes and membrane destabilization. No interaction was observed with dimyristoylphosphatidylcholine (DMPC) membranes, suggesting a specific mechanism for antimicrobial activity.
Area of Science:
- Biochemistry
- Microbiology
- Membrane Biophysics
Background:
- Pediocin PA-1 is a bacteriocin with antimicrobial properties.
- Understanding its interaction with cell membranes is crucial for elucidating its mechanism of action.
Purpose of the Study:
- To investigate the molecular interactions between pediocin PA-1 and model membranes (DMPC and DMPG).
- To determine the effect of these interactions on the secondary structure of pediocin and the conformation of the phospholipids.
Main Methods:
- Fourier transform infrared spectroscopy was employed to study interactions in D2O at pD 6.
- Alterations in pediocin's secondary structure (amide I' band) and phospholipid conformation (methylene and carbonyl stretching vibrations) were monitored.
Main Results:
- Pediocin PA-1 showed no interaction with dimyristoylphosphatidylcholine (DMPC) membranes.
- Pediocin PA-1 underwent structural reorganization upon interaction with dimyristoylphosphatidylglycerol (DMPG) membranes.
- DMPG exhibited a shift in its gel-to-crystalline phase transition to higher temperatures and dehydration.
Conclusions:
- Pediocin PA-1 acts as an extrinsic peptide.
- The antimicrobial action of pediocin PA-1 may involve the destabilization of target cell membranes, particularly those rich in anionic lipids like DMPG.