7SQW image
Entry Detail
PDB ID:
7SQW
Title:
Structure of the KcsA-W67F mutant with the activation gate in the closed conformation
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-11-07
Release Date:
2022-10-12
Method Details:
Experimental Method:
Resolution:
3.21 Å
R-Value Free:
0.27
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
I 4
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Antibody Fragment
Chain IDs:A
Chain Length:219
Number of Molecules:1
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:Antibody Fragment
Chain IDs:B
Chain Length:212
Number of Molecules:1
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:KcsA potassium channel
Mutations:W67F
Chain IDs:C
Chain Length:103
Number of Molecules:1
Biological Source:Streptomyces
Primary Citation
The nonconducting W434F mutant adopts upon membrane depolarization an inactivated-like state that differs from wild-type Shaker-IR potassium channels.
Sci Adv 8 eabn1731 eabn1731 (2022)
PMID: 36112676 DOI: 10.1126/sciadv.abn1731

Abstact

Voltage-gated K+ (Kv) channels mediate the flow of K+ across the cell membrane by regulating the conductive state of their activation gate (AG). Several Kv channels display slow C-type inactivation, a process whereby their selectivity filter (SF) becomes less or nonconductive. It has been proposed that, in the fast inactivation-removed Shaker-IR channel, the W434F mutation epitomizes the C-type inactivated state because it functionally accelerates this process. By introducing another pore mutation that prevents AG closure, P475D, we found a way to record ionic currents of the Shaker-IR-W434F-P475D mutant at hyperpolarized membrane potentials as the W434F-mutant SF recovers from its inactivated state. This W434F conductive state lost its high K+ over Na+ selectivity, and even NMDG+ can permeate, features not observed in a wild-type SF. This indicates that, at least during recovery from inactivation, the W434F-mutant SF transitions to a widened and noncationic specific conformation.

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