Functional Analysis of Native and Recombinant Ion Channels Using a High-Capacity Nonradioactive Rubidium Efflux Assay

Ion channels have lately received much attention by geneticists and molecular biologists owing to the discovery of several inherited human "ion channels disorders". Important contributions to the understanding not only of pathogenesis, but also of the structure-function relationship of ion channels, have come from the functional analysis of these natually occurring mutant channels.

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High Capacity and Superior Rate Performances Coexisting in Carbon-Based Sodium-Ion Battery Anode

Research ◽

10.34133/2019/6930294 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9

Author(s):

Yuqian Li ◽

Liyuan Zhang ◽

Xiuli Wang ◽

Xinhui Xia ◽

Dong Xie ◽

...

Keyword(s):

Ion Channels ◽

High Performance ◽

Specific Capacity ◽

High Capacity ◽

Rate Capability ◽

Sodium Ion ◽

Transformation Rule ◽

High Specific Capacity ◽

Storage Behavior ◽

Fast Ion

Amorphous carbon is considered as a prospective and serviceable anode for the storage of sodium. In this contribution, we illuminate the transformation rule of defect/void ratio and the restrictive relation between specific capacity and rate capability. Inspired by this mechanism, ratio of plateau/slope capacity is regulated via temperature-control pyrolysis. Moreover, pore-forming reaction is induced to create defects, open up the isolated voids, and build fast ion channels to further enhance the capacity and rate ability. Numerous fast ion channels, high ion-electron conductivity, and abundant defects lead the designed porous hard carbon/Co3O4 anode to realize a high specific capacity, prolonged circulation ability, and enhanced capacity at high rates. This research deepens the comprehension of sodium storage behavior and proposes a fabrication approach to achieve high performance carbonaceous anodes for sodium-ion batteries.

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Mechanistic signs of double-barreled structure in a fluoride ion channel

eLife ◽

10.7554/elife.18767 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 13

Author(s):

Nicholas B Last ◽

Ludmila Kolmakova-Partensky ◽

Tania Shane ◽

Christopher Miller

Keyword(s):

Functional Analysis ◽

Ion Channels ◽

Ion Channel ◽

Binding Site ◽

Crystal Structures ◽

Binding Sites ◽

Fluoride Ion ◽

Ion Conduction ◽

Lower Eukaryotes ◽

Dual Pathway

The Fluc family of F− ion channels protects prokaryotes and lower eukaryotes from the toxicity of environmental F−. In bacteria, these channels are built as dual-topology dimers whereby the two subunits assemble in antiparallel transmembrane orientation. Recent crystal structures suggested that Fluc channels contain two separate ion-conduction pathways, each with two F− binding sites, but no functional correlates of this unusual architecture have been reported. Experiments here fill this gap by examining the consequences of mutating two conserved F−-coordinating phenylalanine residues. Substitution of each phenylalanine specifically extinguishes its associated F− binding site in crystal structures and concomitantly inhibits F− permeation. Functional analysis of concatemeric channels, which permit mutagenic manipulation of individual pores, show that each pore can be separately inactivated without blocking F− conduction through its symmetry-related twin. The results strongly support dual-pathway architecture of Fluc channels.

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