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Published on: July 10, 2016
Oligomerization of daptomycin on membranes.
Jawad K Muraih1, Andre Pearson, Jared Silverman
1Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada.
Biochimica Et Biophysica Acta
|January 13, 2011
Summary
Daptomycin antibiotic activity requires oligomerization. This study experimentally demonstrates daptomycin forming membrane-associated oligomers, essential for its antibacterial function against Gram-positive bacteria.
Area of Science:
- Microbiology
- Biochemistry
- Membrane Biophysics
Background:
- Daptomycin is a lipopeptide antibiotic effective against Gram-positive bacteria.
- Its mechanism involves membrane depolarization, but oligomerization has not been experimentally confirmed.
- Previous assumptions suggested oligomerization was key to daptomycin's function.
Purpose of the Study:
- To experimentally demonstrate the formation of membrane-associated oligomers of daptomycin.
- To investigate the conditions required for daptomycin oligomerization.
- To correlate daptomycin oligomerization with its known antibacterial activity.
Main Methods:
- Utilized Förster Resonance Energy Transfer (FRET) between native and NBD-labeled daptomycin.
- Examined oligomerization on membrane vesicles from Bacillus subtilis and model lipid membranes.
- Varied lipid composition (phosphatidylglycerol vs. phosphatidylcholine) and calcium ion presence.
Main Results:
- Daptomycin oligomerization was experimentally demonstrated using FRET.
- Oligomers formed in the presence of calcium ions on membranes containing phosphatidylglycerol.
- Oligomerization did not occur on phosphatidylcholine-only membranes or in solution.
Conclusions:
- Daptomycin forms membrane-associated oligomers, confirming previous hypotheses.
- Oligomerization is dependent on calcium ions and negatively charged phospholipids.
- These findings strongly suggest daptomycin oligomerization is a prerequisite for its antibacterial activity.
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