Gramicidin as an Example of a Single‐filing Ionic Channel*

Eisenman, George; Enos, B.; Hägglund, Jarl V.; Sandblom, John

doi:10.1111/j.1749-6632.1980.tb15964.x

Cited by 49 publications

(91 citation statements)

References 19 publications

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“…However, between pH 1 and pH 0, the H' conductance continues to increase in direct proportion with [H']. The data assembled by Eisenman et al 35 are plotted with a different symbol ( 0) to emphasize the inflection between pH 1 and pH 2. This inflection was noted by the authors and was ascribed to multiple occupancy of the gramicidin channel by H' .…”

Section: ( I ) Saturation At Low P Hmentioning

confidence: 98%

An Electrophysiological Comparison of Voltage‐Gated Proton Channels, Other Ion Channels, and Other Proton Channels

DeCoursey

Cherny

1999

Israel Journal of Chemistry

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Abstract. Voltage-gated proton selective channels occupy an ill-defined region between "normal" ion channels and a variety of proton-conducting pathways inside proteins, including, but not limited to, membrane-bound proteins. Voltage-gated H+ channels closely resemble other voltage-gated ion channels in their voltage-and time-dependent gating, but differ in their extreme selectivity, their miniscule singlechannel conductance, and the high activation enthalpy for conduction. Furthermore, in contrast with the "multiple occupancy" hypothesized to account for aspects of permeation through other ion channels, it seems unlikely that H' channels can be occupied by more than one proton at a time. Voltage-gated H+ channels functionally resemble other proton-conducting pathways in proteins, but until their structure has been determined, this similarity will remain speculative. The present restriction to functional measurements is less of a handicap than might be expected-the history of ion channel research shows that deductions based on electrophysiological measurements often closely predict the eventually determined structure. Existing evidence supports the idea that protons permeate the membrane through voltage-gated H+ channels by hopping across a hydrogen-bonded chain that consists of at least some amino acid side groups in addition to water molecules.

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Section: ( I ) Saturation At Low P Hmentioning

confidence: 98%

An Electrophysiological Comparison of Voltage‐Gated Proton Channels, Other Ion Channels, and Other Proton Channels

DeCoursey

Cherny

1999

Israel Journal of Chemistry

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show abstract

“…extracellular) side of the membrane. In symmetrical systems (e.g., symmetrical bilayers with gramicidin channels or artificial carriers) an hyperbolic (i.e., supralinear) I-V shape implies that a barrier deep within the membrane is rate determining, whereas a saturating (i.e., sublinear) I-V shape signifies that the barriers at the surface are more important (cf [29,79,81,123]). …”

Section: How the Energy Profile Is Characterizedmentioning

confidence: 99%

Ionic selectivity revisited: The role of kinetic and equilibrium processes in ion permeation through channels

Eisenman¹,

Horn²

1983

J. Membrain Biol.

528

396

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“…For instance, the 'selectivity' of the gramicidin channel for Tl+ over Na+ (see Neher, 1975;Urban, Hladky & Haydon, 1978;Eisenmann, Enos, Hagglund & Sandblom, 1980) has previously been treated with theories similar to the one used here, and may be viewed as being due to a higher affinity for Tl+. Also, K+ channels have long been recognized to be single-file pores Ca2+ AND Ca2+ CHANNEL SELECTIVITY (for review see Hille & Schwarz, 1978) and it is conceivable that their remarkable selectivity for K+ owes much to selective binding of K+ to sites in the channel.…”

Section: A Model For Ion Permeation Through Caa2+ Channelsmentioning

confidence: 99%

Non‐selective conductance in calcium channels of frog muscle: calcium selectivity in a single‐file pore.

Almers¹,

McCleskey²

1984

The Journal of Physiology

609

495

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Gramicidin as an Example of a Single‐filing Ionic Channel*

Cited by 49 publications

References 19 publications

An Electrophysiological Comparison of Voltage‐Gated Proton Channels, Other Ion Channels, and Other Proton Channels

An Electrophysiological Comparison of Voltage‐Gated Proton Channels, Other Ion Channels, and Other Proton Channels

Ionic selectivity revisited: The role of kinetic and equilibrium processes in ion permeation through channels

Non‐selective conductance in calcium channels of frog muscle: calcium selectivity in a single‐file pore.

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