2AHY

Na+ complex of the NaK Channel


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.236 
  • R-Value Observed: 0.236 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Atomic structure of a Na+- and K+-conducting channel.

Shi, N.Ye, S.Alam, A.Chen, L.Jiang, Y.

(2006) Nature 440: 570-574

  • DOI: https://doi.org/10.1038/nature04508
  • Primary Citation of Related Structures:  
    2AHY, 2AHZ

  • PubMed Abstract: 

    Ion selectivity is one of the basic properties that define an ion channel. Most tetrameric cation channels, which include the K+, Ca2+, Na+ and cyclic nucleotide-gated channels, probably share a similar overall architecture in their ion-conduction pore, but the structural details that determine ion selection are different. Although K+ channel selectivity has been well studied from a structural perspective, little is known about the structure of other cation channels. Here we present crystal structures of the NaK channel from Bacillus cereus, a non-selective tetrameric cation channel, in its Na+- and K+-bound states at 2.4 A and 2.8 A resolution, respectively. The NaK channel shares high sequence homology and a similar overall structure with the bacterial KcsA K+ channel, but its selectivity filter adopts a different architecture. Unlike a K+ channel selectivity filter, which contains four equivalent K+-binding sites, the selectivity filter of the NaK channel preserves the two cation-binding sites equivalent to sites 3 and 4 of a K+ channel, whereas the region corresponding to sites 1 and 2 of a K+ channel becomes a vestibule in which ions can diffuse but not bind specifically. Functional analysis using an 86Rb flux assay shows that the NaK channel can conduct both Na+ and K+ ions. We conclude that the sequence of the NaK selectivity filter resembles that of a cyclic nucleotide-gated channel and its structure may represent that of a cyclic nucleotide-gated channel pore.


  • Organizational Affiliation

    Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Potassium channel protein
A, B
110Bacillus cereusMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for Q81HW2 (Bacillus cereus (strain ATCC 14579 / DSM 31 / CCUG 7414 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NCTC 2599 / NRRL B-3711))
Explore Q81HW2 
Go to UniProtKB:  Q81HW2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ81HW2
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.236 
  • R-Value Observed: 0.236 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.528α = 90
b = 85.482β = 90
c = 129.572γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
MLPHAREphasing
CNSrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-02-07
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations