Channel-forming activity of syringopeptin 25A in mercury-supported lipid bilayers with a phosphatidylcholine distal leaflet

摘要: The channel-forming activity of the lipodepsipeptide syringopeptin 25A (SP25A) was investigated at a tethered bilayer lipid membrane (tBLM) with dioleoylphosphatidylcholine distal leaflet, anchored to mercury electrode through hydrophilic tetraethyleneoxy spacer. SP25A incorporated in tBLM from different aqueous solutions by recording series impedance spectra over potential range encompassing non-physiological transmembrane (Δϕ) values. Once incorporated, forms stable ion channels narrower physiological Δϕ Ion flow into and out spacer, moiety tBLM, monitored step chronocoulometry cyclic voltammetry pH3, 5.4 6.8. Potassium spacer along channels, during negative scan, proceeds two stages, except higher pH lower concentration adopted, where it single stage. In light behavior channel currents reported literature, first stage is ascribed large resulting aggregation small ones, while second more associated disaggregation ones.