Cluster Organization of Ion Channels Formed by the Antibiotic Syringomycin E in Bilayer Lipid Membranes

Kaulin, Yuri A.; Schagina, Ludmila V.; Bezrukov, Sergey M.; Malev, V. V.; Feǐgin, A. M.; Takemoto, Jon Y.; Teeter, John H.; Brand, Joseph G.

doi:10.1016/s0006-3495(98)77999-8

Cited by 68 publications

(61 citation statements)

References 24 publications

(30 reference statements)

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“…The peaks with the amplitude different from the smallest absolute mean current by a factor of two (or multiplicity factor k = 2, see Section 2) can be interpreted as a random simultaneous opening of two small channels. Other current peaks on the histograms (k > 2) cannot be explained by stochastic coincidence of channel opening/closure [14] and, thus, they correspond to the activity of clusters, i.e., to the synchronous opening/closure of k small SRE channels.…”

Section: Resultsmentioning

confidence: 99%

“…The area under the peak-approximating curve used to calculate the probability of a certain level of current fluctuations. In order to distinguish between synchronous openings of several small channels in a cluster and random openings of several small channels we used the statistical approach described by Kaulin et al [14].…”

Section: Methodsmentioning

confidence: 99%

“…To address this question, we studied the cluster organization of the pore forming toxin syringomycin E (SRE) [12][13][14][15][16][17][18][19][20][21]. When incorporated into planar lipid bilayers, SRE forms two types of voltage-gated ion channels with small and large current amplitudes [15,22].…”

Section: Introductionmentioning

confidence: 99%

“…When incorporated into planar lipid bilayers, SRE forms two types of voltage-gated ion channels with small and large current amplitudes [15,22]. These two types of channels are identical by ion selectivity and polymer exclusion properties, i.e., have identical inner radii [14,15], which led us to conclude that the ''large'' channels are clusters of the ''small'' ones. At one-sided SRE addition the kinetics of channel opening (or closure) and the channel conductance are strongly voltage dependent and pronouncedly asymmetric [15,22].…”

Section: Introductionmentioning

confidence: 99%

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Voltage‐dependent synchronization of gating of syringomycin E ion channels

et al. 2005

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Antifungal lipodepsipeptide syringomycin E (SRE) forms two major conductive states in lipid bilayers: ''small'' and ''large''. Large SRE channels are cluster of several small ones, demonstrating synchronous opening and closure. To get insight into the mechanism of such synchronization we investigated how transmembrane potential, membrane surface charge, and ionic strength affect the number of small SRE channels synchronously functioning in the cluster. Here, we report that the large SRE channels can be presented as 3-8 simultaneously gating small channels. The increase in the absolute value of the transmembrane potential (from 50 to 200 mV) decreases the number of synchronously gated channels in the clusters. Voltage-dependence of channel synchronization was influenced by the ionic strength of the bathing solution, but not by membrane surface charge. We propose a mechanism for the voltage-dependent cluster behavior that involves a voltage-induced reorientation of lipid dipoles associated with the channel pores.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Voltage‐dependent synchronization of gating of syringomycin E ion channels

et al. 2005

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“…However, in this case the contribution to the overall lipid charge from PS was small, in view of its low mole fraction. It should be noted that the particular behavior of the SP25A channel at a DPTL/ DOPS tBLM in a solution of 0.1 M KCl, pH 6.8, parallels that of the syringomycin E channel, which is closed at positive transmembrane potentials at a DOPS [43] and a DOPS/DOPE BLM in 0.1 M NaCl, pH 6 [44], while it is open at a DOPS/DOPE BLM in 0.1 M NaCl, pH 2, and at a diphytanoylPC BLM in 0.1 M NaCl, pH 6 [44].…”

Section: Dptl/dops Tblm In a Buffer Solution Ph 68mentioning

confidence: 80%

Channel-forming activity of syringopeptin 25A in mercury-supported phospholipid monolayers and negatively charged bilayers

Becucci

Toppi

Fiore

et al. 2016

Bioelectrochemistry

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Interactions of the cationic lipodepsipeptide syringopeptin 25A (SP25A) with mercury-supported dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylserine (DOPS) and dioeleoylphosphatidic acid (DOPA) self-assembled monolayers (SAMs) were investigated by AC voltammetry in 0.1M KCl at pH3, 5.4 and 6.8. SP25A targets and penetrates the DOPS SAM much more effectively than the other SAMs not only at pH6.8, where the DOPS SAM is negatively charged, but also at pH3, where it is positively charged just as SP25A. Similar investigations at tethered bilayer lipid membranes (tBLMs) consisting of a thiolipid called DPTL anchored to mercury, with a DOPS, DOPA or DOPC distal monolayer on top of it, showed that, at physiological transmembrane potentials, SP25A forms ion channels spanning the tBLM only if DOPS is the distal monolayer. The distinguishing chemical feature of the DOPS SAM is the ionic interaction between the protonated amino group of a DOPS molecule and the carboxylate group of an adjacent phospholipid molecule. Under the reasonable assumption that SP25A preferentially interacts with this ion pair, the selective lipodepsipeptide antimicrobial activity against Gram-positive bacteria may be tentatively explained by its affinity for similar protonated amino-carboxylate pairs, which are expected to be present in the peptide moieties of peptidoglycan strands.

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Functional activity of peptide ion channels in tethered bilayer lipid membranes: Review

Guidelli

Becucci²

2021

Electrochemical Science Adv

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Ion transport across biomembranes plays a major role in living cells. This fundamental function is normally carried out by molecules with both a hydrophobic and a hydrophilic side (amphiphilic molecules), which aggregate within the membrane forming a hydrophilic pore (the ion channel) permitting the selective translocation of permeant ions. Countless papers report the conformation of these ion channels in lipid vesicles using several techniques, such as circular dichroism and solid‐state NMR spectroscopies. However, the functional activity of ion channels can only be investigated by varying the transmembrane potential. This is also the situation in which ion channels operate in commercialized drugs with intracellular targeting activities, of great interest in pharmaceutical research. A suitable biomimetic membrane must consist of a conducting or semiconducting support, whose “heart” is a lipid bilayer in contact with the aqueous solution of interest on one side. The other side must comprise a hydrophilic region thick enough to completely decouple the lipid bilayer from the support, giving rise to a “tethered bilayer lipid membrane” (tBLM). This review aims to describe the numerous efforts made over time to approach this goal, the most recent achievements, and the perspectives of future development. Special emphasis will be placed on the electrochemical aspects of tBLMs, and a qualitative overview of the main optical and scanning probe techniques employed will be provided.

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Cluster Organization of Ion Channels Formed by the Antibiotic Syringomycin E in Bilayer Lipid Membranes

Cited by 68 publications

References 24 publications

Voltage‐dependent synchronization of gating of syringomycin E ion channels

Voltage‐dependent synchronization of gating of syringomycin E ion channels

Channel-forming activity of syringopeptin 25A in mercury-supported phospholipid monolayers and negatively charged bilayers

Functional activity of peptide ion channels in tethered bilayer lipid membranes: Review

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