Voltage-dependent conductance induced by alamethicin-phospholipid conjugates in lipid bilayers.
Alamethicin, a linear 20-amino acid antibiotic, forms voltage-dependent channels in lipid bilayer membranes. We show here that alamethicin-phospholipid conjugates can be prepared by photolysis of unilamellar vesicles containing alamethicin and a phosphatidylcholine analogue with a carbene precursor at the end of the C-2 fatty acyl chain. This result indicates that at least a portion of the alamethicin molecule is in contact with the hydrocarbon moiety of the membrane in the absence of an applied voltage. Furthermore, the alamethicin-phospholipid photoproduct is able to induce a voltage-gated conductance similar to that of natural alamethicin. The importance of these results in terms of mechanisms for channel gating is discussed.
D000408:Alamethicin; D000900:Anti-Bacterial Agents; D004553:Electric Conductivity; D004563:Electrochemistry; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010743:Phospholipids; D010777:Photochemistry
D000900:Anti-Bacterial Agents; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010743:Phospholipids; D000408:Alamethicin