Abstract
The mechanism of membrane permeabilization by the antifungal heptaene macrolide amphotericin B (AmB) was investigated by using two different mercury-supported biomimetic membranes, namely a lipid self-assembled monolayer and a lipid bilayer tethered to the mercury surface through a hydrophilic spacer (tethered bilayer lipid membrane: tBLM). The disruptive permeabilization of a sterol-free mercury-supported lipid monolayer by low AmB concentrations, after a sufficiently long exposure to the macrolide, suggests a similar effect on the distal lipid monolayer of vesicular or bilayer lipid membranes. The notable permeabilization of a tBLM to Cd(II), with amalgam formation, by 0.6μM AmB complexed with sterols in a 1:3 molar ratio, as compared with the absence of any effect in the absence of sterols, suggests a direct participation of sterols in ion channel formation. The fact that the tBLM permeabilization requires the presence in solution of a freshly added AmB–sterol mixture and of Cd(II) or Ca2+ ions points out the notable role played by these divalent inorganic ions in the formation of AmB ion channels. Ion channels formed in a tBLM by AmB–ergosterol complexes are stable at physiological transmembrane potentials, whereas those formed by AmB–cholesterol complexes require application of non-physiological transmembrane potentials for their stability.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
