Cation selective ion channels formed by macrodiolide antibiotic elaiophylin in lipid bilayer membranes

• Published in: Bioelectrochemistry (Amsterdam, Netherlands) Vol. 54; no. 1; pp. 11 - 15
• Main Authors: Grigoriev, P.A., Schlegel, R., Gräfe, U.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2001
• Subjects: Anti-Bacterial Agents - chemistry; Antibiotic elaiophylin; Bilayer lipid membrane; Cations; Ion Channel Gating; Ion channels; Ion Channels - chemistry; Ion selectivity; Lipid Bilayers; Macrolides; Membrane Potentials; Membranes, Artificial; Antibiotic elaiophylin; Bilayer lipid membrane; Ion channels; Ion selectivity
• ISSN: 1567-5394
• DOI: 10.1016/S0302-4598(01)00102-7

The macrodiolide antibiotic elaiophylin ( 1) forms stable, long-lasting cation selective ion channels in planar lipid bilayer membranes prepared from soybean phosphatidylcholine. Current of the single ion channel displayed two sublevels corresponding to the two substates of the channel conductance: a slow substate, with about 5 s of mean dwell time in the open state at 40% level of the total amplitude conductance, and a fast substate of higher conductance with dwell times in the open and closed state of about 0.1 s. Amplitude conductances of the single ion channels in 200 mM of LiCl, NaCl, KCl, RbCl and CsCl were 75, 140, 220, 240 and 226 pS, and the conductance was linear function of the electrolyte concentration. Ratios of cation to anion permeabilities of the channel for NaCl and KCl were 8±2 and >24, respectively. A molecular model of the channel structure is suggested.