A lipid vesicle system for probing voltage-dependent peptide–lipid interactions: Application to alamethicin channel formation
✍ Scribed by G. Andrew Woolley; Charles M. Deber
- Book ID
- 101719674
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1989
- Tongue
- English
- Weight
- 367 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Synopsis
A membrane potential is shown to be established in phosphatidylcholine/cholesterol unilamellar vesicles using valinomycin in conjunction with a potassium ion gradient; this potential is monitored using the externally added fluorescent dye Safranine 0. In the same system, transmembrane calcium fluxes are then detected using the (internally trapped) fluorescent dye Quin-2. The calcium-transport behavior of the channel-forming peptide alamethicin is shown to be potential dependent in this system, in contrast to calcium transport by the ionophore Br-A23187, which is unaffected by the potential. The observation of this potential-dependent behavior for alamethicin suggests that this vesicle system may be suitable for direct spectroscopic observation of the voltage-gating process.