Structural basis for ion selectivity in TMEM175 K+ channels

Structural basis of ion permeation gating in Slo2.1 K+ channels

The activation gate of ion channels controls the transmembrane flux of permeant ions. In voltage-gated K(+) channels, the aperture formed by the S6 bundle crossing can widen to open or narrow to close the ion permeation pathway, whereas the selectivity filter gates ion flux in cyclic-nucleotide gated (CNG) and Slo1 channels. Here we explore the structural basis of the activation gate for Slo2.1...

Ion conduction and selectivity in K(+) channels.

Potassium (K(+)) channels are tetrameric membrane-spanning proteins that provide a selective pore for the conductance of K(+) across the cell membranes. These channels are most remarkable in their ability to discriminate K(+) from Na(+) by more than a thousandfold and conduct at a throughput rate near diffusion limit. The recent progress in the structural characterization of K(+) channel provid...

Ion Conduction and Selectivity in K+ Channels

An Ingenious Filter: the Structural Basis for Ion Channel Selectivity

channel from Streptomyces lividans, was readily overex-pressed in bacteria (Schrempf et al., 1995). Its primary sequence is related to the class of ion-selective channels called inwardly rectifying channels, as evidenced by the presence of two putative transmembrane helices with the ion selectivity–determining P region residing Neurobiology has taken a giant step forward: we know, between them ...

Ion selectivity and current saturation in inward-rectifier K+ channels

We investigated the features of the inward-rectifier K channel Kir1.1 (ROMK) that underlie the saturation of currents through these channels as a function of permeant ion concentration. We compared values of maximal currents and apparent K(m) for three permeant ions: K(+), Rb(+), and NH(4)(+). Compared with K(+) (i(max) = 4.6 pA and K(m) = 10 mM at -100 mV), Rb(+) had a lower permeability, a lo...