Channel Current Analysis for Pore-forming Properties of an Antimicrobial Peptide, Magainin 1, Using the Droplet Contact Method

Abstract

This study describes the pore-forming properties of magainin 1 in planar lipid bilayers. These bilayers were prepared by the droplet contact method, which was executed on a microfabricated device for a high-throughput study. We arrayed four droplet chambers parallelly in the single device, and the current measurements were carried out simultaneously. Using this system, we measured the channel current conductance of magainin 1. We determined the pore size and the number of assembling monomers in magainin pores in mammalian and bacterial model membranes. This system is a powerful tool for analyzing transmembrane peptides and their antimicrobial activities.

The Mechanisms of Action of Cationic Antimicrobial Peptides Refined by Novel Concepts from Biophysical Investigations

“…Notably, discrete single-channel openings/ events are rather difficult to observe for magainins and cecropins because most of the time, these peptides lyse the membranes. However, in some electrophysiological experiments, discrete multilevel conductivities have been recorded (Christensen et al 1988;Duclohier et al 1989;Cruciani et al 1991;Watanabe and Kawano 2016), which early on was taken as an indicator for transmembrane helical bundle formation (Tieleman et al 2002). However, unlike the welldefined ion channels formed by alamethicin, those recorded in the presence of cationic amphipathic peptides are erratic and characterized by large variations (Christensen et al 1988;Duclohier et al 1989;Cruciani et al 1991).…”

“…Transmembrane alignments have been found unstable, and little direct interactions between the peptides have been observed. Openings can form by stochastic rearrangements of peptides and lipids rather than through well-defined supramolecular assemblies, which could explain the early observations during electrophysiological recordings (Christensen et al 1988;Duclohier et al 1989;Cruciani et al 1991;Watanabe and Kawano 2016). In order to visualize local or global changes in the membrane macroscopic phase or membrane lysis, including the all-or-nothing release observed in dye release experiments (Gregory et al 2008;Tamba et al 2010), larger systems would need to be simulated over longer time scales.…”

Hairpin DNA Unzipping Analysis Using a Biological Nanopore Array

“…12 Furthermore, we constructed a droplet array for high-throughput measurements. 13 Using bilayer lipid membranes (BLMs), we measured various membrane proteins and biological nanopore, for example, single molecule detection using DNA aptamers, 14 high-throughput ion channel measurements at the single-protein level, 13,15,16 solutionexchange techniques via the microdroplet system, 17 and the development of portable nanopore sensors. 18 In this study, we Figure 1.…”

Synthetic Ion Channels and DNA Logic Gates as Components of Molecular Robots

“…In addition, physical dynamics such as membrane fusion and endo‐ or exocytosis, such as molecular uptake processes, are useful for the interface of the robots. We previously developed a high‐throughput planar BLM (pBLM) system that will be a powerful tool for the manufacturing of the lipid body of molecular robots . A pBLM is generally used as the ion current measurement of an ion channel or pore‐forming proteins.…”

“…We previously developed ah igh-throughput planar BLM (pBLM) system that will be ap owerful tool for the manufacturing of the lipid body of molecular robots. [10][11][12] Ap BLM is generally used as the ion current measurement of an ion channel or pore-forming proteins. Because the reproducibility and stability of pBLMs are conventionally insufficient, variousm ethods have been proposed to overcome this, primarily using microfluidic technology.…”