High resolution open MthK pore structure crystallized in 100 mM K+

Experimental Data Snapshot

  • Resolution: 1.45 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.188 

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This is version 1.3 of the entry. See complete history


Novel insights into K(+) selectivity from high-resolution structures of an open K(+) channel pore.

Ye, S.Li, Y.Jiang, Y.

(2010) Nat Struct Mol Biol 17: 1019-1023

  • DOI: https://doi.org/10.1038/nsmb.1865
  • Primary Citation of Related Structures:  
    3LDC, 3LDD, 3LDE

  • PubMed Abstract: 

    K+ channels are highly selective for K+ over Na+. Here we present several crystal structures of the MthK K+ channel pore at up to 1.45-A resolution. The MthK selectivity filter maintains a conductive conformation even in the absence of K+, allowing the channel to conduct Na+. The high-resolution structures, along with single-channel recordings, allow for an accurate analysis of how K+ competes with Na+ in a conductive selectivity filter. At high K+ concentrations, two K+ ions equivalently occupy the four sites in the selectivity filter, whereas at low K+/high Na+ concentrations, a single K+ ion remains bound in the selectivity filter, preferably at site 1 or site 3. This single K+ binding at low concentration effectively blocks the permeation of Na+, providing a structural basis for the anomalous mole-fraction effect, a key property of multi-ion pores.

  • Organizational Affiliation

    Life Sciences Institute, Zhejiang University, Zhejiang, China. sye@zju.edu.cn

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calcium-gated potassium channel mthK82Methanothermobacter thermautotrophicus str. Delta HMutation(s): 2 
Gene Names: mthKMTH_1520
Membrane Entity: Yes 
Find proteins for O27564 (Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H))
Explore O27564 
Go to UniProtKB:  O27564
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO27564
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.45 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.188 
  • Space Group: P 4 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.811α = 90
b = 63.811β = 90
c = 44.05γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

  • Released Date: 2010-08-11 
  • Deposition Author(s): Ye, S.

Revision History  (Full details and data files)

  • Version 1.0: 2010-08-11
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-13
    Changes: Database references, Derived calculations
  • Version 1.3: 2023-09-06
    Changes: Data collection, Refinement description