3TCU image
Deposition Date 2011-08-09
Release Date 2011-10-05
Last Version Date 2024-02-28
Entry Detail
PDB ID:
3TCU
Title:
Crystal Structure of NaK2K Channel D68E Mutant
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.75 Å
R-Value Free:
0.22
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
I 4
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Potassium channel protein
Gene (Uniprot):BC_0669
Mutations:D66Y, N68E
Chain IDs:A, B
Chain Length:97
Number of Molecules:2
Biological Source:Bacillus cereus
Primary Citation
Protein interactions central to stabilizing the K+ channel selectivity filter in a four-sited configuration for selective K+ permeation.
Proc.Natl.Acad.Sci.USA 108 16634 16639 (2011)
PMID: 21933962 DOI: 10.1073/pnas.1111688108

Abstact

The structural and functional conversion of the nonselective NaK channel to a K(+) selective channel (NaK2K) allows us to identify two key residues, Tyr and Asp in the filter sequence of TVGYGD, that participate in interactions central to stabilizing the K(+) channel selectivity filter. By using protein crystallography and channel electrophysiology, we demonstrate that the K(+) channel filter exists as an energetically strained structure and requires these key protein interactions working in concert to hold the filter in the precisely defined four-sited configuration that is essential for selective K(+) permeation. Disruption of either interaction, as tested on both the NaK2K and eukaryotic K(v)1.6 channels, can reduce or completely abolish K(+) selectivity and in some cases may also lead to channel inactivation due to conformational changes at the filter. Additionally, on the scaffold of NaK we recapitulate the protein interactions found in the filter of the Kir channel family, which uses a distinct interaction network to achieve similar stabilization of the filter.

Legend

Protein

Chemical

Disease

Primary Citation of related structures