Ion Channels

Andersen, Olaf S.; Ingólfsson, Helgi I.; Lundbæk, Jens August

doi:10.1002/3527600434.eap673

Cited by 3 publications

(3 citation statements)

References 172 publications

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“…Adjustments of conductance in response to chemical stimuli are an essential biological function of canonical ion channels in living cells [18,21,22], and such features may be replicated in vitro for sensing purposes. However, ion channel reconstitution in artificial membrane systems is not always an easy task [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Lysenin Channels as Sensors for Ions and Molecules

Bogard

Abatchev

Hutchinson

et al. 2020

Sensors

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Lysenin is a pore-forming protein extracted from the earthworm Eisenia fetida, which inserts large conductance pores in artificial and natural lipid membranes containing sphingomyelin. Its cytolytic and hemolytic activity is rather indicative of a pore-forming toxin; however, lysenin channels present intricate regulatory features manifested as a reduction in conductance upon exposure to multivalent ions. Lysenin pores also present a large unobstructed channel, which enables the translocation of analytes, such as short DNA and peptide molecules, driven by electrochemical gradients. These important features of lysenin channels provide opportunities for using them as sensors for a large variety of applications. In this respect, this literature review is focused on investigations aimed at the potential use of lysenin channels as analytical tools. The described explorations include interactions with multivalent inorganic and organic cations, analyses on the reversibility of such interactions, insights into the regulation mechanisms of lysenin channels, interactions with purines, stochastic sensing of peptides and DNA molecules, and evidence of molecular translocation. Lysenin channels present themselves as versatile sensing platforms that exploit either intrinsic regulatory features or the changes in ionic currents elicited when molecules thread the conducting pathway, which may be further developed into analytical tools of high specificity and sensitivity or exploited for other scientific biotechnological applications.

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Section: Introductionmentioning

confidence: 99%

Lysenin Channels as Sensors for Ions and Molecules

Bogard

Abatchev

Hutchinson

et al. 2020

Sensors

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“…In fact, some natural systems have evolved in directing the Brownian motion by using ion/molecular channels. 9,10 Enzymes, however, often utilize aromatic groups in their backbone as gates for controlling the rate by which molecules access their active site and thereby the selectivity of chemical reactions occurring in their interior. 11 Notably, the function of ion/molecular channels as well as enzymes relies on molecular recognition allowing fine-tuning of the rate by which molecules travel and change their environment (Fig.…”

Section: Introductionmentioning

confidence: 99%

Controlling the dynamics of molecular encapsulation and gating

et al. 2011

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This critical review describes mechanisms by which guest molecules enter and depart molecular capsules. The discussion focuses on presenting gated molecular encapsulation, i.e., trapping and releasing of guest molecules at rates that are controlled by conformational changes in the host's structure. Developing quantitative rules that describe the gating are, at present, a matter of scientific curiosity but could play an important role in building more effective catalysts, drug-delivery devices or membranes (105 references).

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“…It has been suggested that lysenin channels alter their conformation by the movement of a gate coupled to a charged voltage domain sensor when under the influence of an external electric field [ 6 ], which is functionally similar to many voltage-gated ion channels [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Structural data reveals the presence of hinge-like, flexible structures essential for pore formation [ 19 , 20 , 21 ] which may allow the elusive voltage domain sensor to move.…”

Section: Introductionmentioning

confidence: 99%

Insights into the Voltage Regulation Mechanism of the Pore-Forming Toxin Lysenin

Bryant

Clark

Thomas

et al. 2018

Toxins

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Lysenin, a pore forming toxin (PFT) extracted from Eisenia fetida, inserts voltage-regulated channels into artificial lipid membranes containing sphingomyelin. The voltage-induced gating leads to a strong static hysteresis in conductance, which endows lysenin with molecular memory capabilities. To explain this history-dependent behavior, we hypothesized a gating mechanism that implies the movement of a voltage domain sensor from an aqueous environment into the hydrophobic core of the membrane under the influence of an external electric field. In this work, we employed electrophysiology approaches to investigate the effects of ionic screening elicited by metal cations on the voltage-induced gating and hysteresis in conductance of lysenin channels exposed to oscillatory voltage stimuli. Our experimental data show that screening of the voltage sensor domain strongly affects the voltage regulation only during inactivation (channel closing). In contrast, channel reactivation (reopening) presents a more stable, almost invariant voltage dependency. Additionally, in the presence of anionic Adenosine 5′-triphosphate (ATP), which binds at a different site in the channel’s structure and occludes the conducting pathway, both inactivation and reactivation pathways are significantly affected. Therefore, the movement of the voltage domain sensor into a physically different environment that precludes electrostatically bound ions may be an integral part of the gating mechanism.

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Ion Channels

Cited by 3 publications

References 172 publications

Lysenin Channels as Sensors for Ions and Molecules

Lysenin Channels as Sensors for Ions and Molecules

Controlling the dynamics of molecular encapsulation and gating

Insights into the Voltage Regulation Mechanism of the Pore-Forming Toxin Lysenin

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