Modulation of Voltage-Gating and Hysteresis of Lysenin Channels by Cu2+ Ions

Bogard, Andrew; Finn, Pangaea W.; Smith, Aviana R.; Flacau, Ilinca M.; Whiting, Rose; Fologea, Daniel

doi:10.3390/ijms241612996

Cited by 1 publication

(2 citation statements)

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“…While the effect has been demonstrated in the context of channel-facilitated transport, to the best of our knowledge, it has not previously been linked to changes in channel conformations [53][54][55]. Although it was previously observed that not only the bathing electrolyte composition [19,[56][57][58] but also the electrolyte concentration [19,59,60] can influence β-barrel channel gating, in the present study, we limited ourselves to 1 M salt solutions because our goal here was to demonstrate the existence of the Hofmeister effect in the voltage-induced OmpF closure.…”

Section: Resultsmentioning

confidence: 84%

“…conformations [53][54][55]. Although it was previously observed that not only the bathing electrolyte composition [19,[56][57][58] but also the electrolyte concentration [19,59,60] can influence β-barrel channel gating, in the present study, we limited ourselves to 1 M salt solutions because our goal here was to demonstrate the existence of the Hofmeister effect in the voltage-induced OmpF closure. It is well-known that the voltage-induced closing of β-barrel channels depends on the composition of lipid membranes [60][61][62][63][64][65][66][67][68].…”

Section: Resultsmentioning

confidence: 96%

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Beta-Barrel Channel Response to High Electric Fields: Functional Gating or Reversible Denaturation?

Nestorovich,

Bezrukov

2023

IJMS

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Ion channels exhibit gating behavior, fluctuating between open and closed states, with the transmembrane voltage serving as one of the essential regulators of this process. Voltage gating is a fundamental functional aspect underlying the regulation of ion-selective, mostly α-helical, channels primarily found in excitable cell membranes. In contrast, there exists another group of larger, and less selective, β-barrel channels of a different origin, which are not directly associated with cell excitability. Remarkably, these channels can also undergo closing, or “gating”, induced by sufficiently strong electric fields. Once the field is removed, the channels reopen, preserving a memory of the gating process. In this study, we explored the hypothesis that the voltage-induced closure of the β-barrel channels can be seen as a form of reversible protein denaturation by the high electric fields applied in model membranes experiments—typically exceeding twenty million volts per meter—rather than a manifestation of functional gating. Here, we focused on the bacterial outer membrane channel OmpF reconstituted into planar lipid bilayers and analyzed various characteristics of the closing-opening process that support this idea. Specifically, we considered the nearly symmetric response to voltages of both polarities, the presence of multiple closed states, the stabilization of the open conformation in channel clusters, the long-term gating memory, and the Hofmeister effects in closing kinetics. Furthermore, we contemplate the evolutionary aspect of the phenomenon, proposing that the field-induced denaturation of membrane proteins might have served as a starting point for their development into amazing molecular machines such as voltage-gated channels of nerve and muscle cells.

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