Channel Formation and Membrane Deformation via Sterol-Aided Polymorphism of Amphidinol

Masayuki Iwamoto, Ayumi Sumino, Eri Shimada, Masanao Kinoshita, Nobuaki Matsumori, Shigetoshi Oiki

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Amphidinol 3 (AM3) is an anti-fungal polyene extracted from a marine dinoflagellate. Here, we examined the ion channel activity and membrane-embedded structure of AM3 using a lipid bilayer method and atomic force microscopy (AFM). AM3 exhibited large-conductance (∼1 nS) and non-selective single-channel activity only when sterols were present in the membrane leaflet of the AM3-added side. The variable conductance suggests the formation of a multimeric barrel-stave pore. At high AM3 concentrations, giant-conductance "jumbo" channels (∼40 nS) emerged. AFM revealed a thicker raft-like membrane phase with the appearance of a wrinkled surface, in which phase pores (diameter: ∼10 nm) were observed. The flip-flop of ergosterol occurred only after the appearance of the jumbo channel, indicating that the jumbo channel induced a continuity between the outer and inner leaflets of the membrane: a feature characteristic of toroidal-like pores. Thus, AM3 forms different types of sterol-aided polymorphic channels in a concentration dependent manner.

Original languageEnglish
Article number10782
JournalScientific reports
Volume7
Issue number1
DOIs
Publication statusPublished - Dec 1 2017

All Science Journal Classification (ASJC) codes

  • General

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