4QE9

Open MthK pore structure soaked in 10 mM Ba2+/100 mM K+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Ionic interactions of Ba2+ blockades in the MthK K+ channel

Guo, R.Zeng, W.Cui, H.Chen, L.Ye, S.

(2014) J.Gen.Physiol. 144: 193-200

  • DOI: 10.1085/jgp.201411192
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The movement and interaction of multiple ions passing through in single file underlie various fundamental K(+) channel properties, from the effective conduction of K(+) ions to channel blockade by Ba(2+) ions. In this study, we used single-channel el ...

    The movement and interaction of multiple ions passing through in single file underlie various fundamental K(+) channel properties, from the effective conduction of K(+) ions to channel blockade by Ba(2+) ions. In this study, we used single-channel electrophysiology and x-ray crystallography to probe the interactions of Ba(2+) with permeant ions within the ion conduction pathway of the MthK K(+) channel. We found that, as typical of K(+) channels, the MthK channel was blocked by Ba(2+) at the internal side, and the Ba(2+)-blocking effect was enhanced by external K(+). We also obtained crystal structures of the MthK K(+) channel pore in both Ba(2+)-Na(+) and Ba(2+)-K(+) environments. In the Ba(2+)-Na(+) environment, we found that a single Ba(2+) ion remained bound in the selectivity filter, preferably at site 2, whereas in the Ba(2+)-K(+) environment, Ba(2+) ions were predominantly distributed between sites 3 and 4. These ionic configurations are remarkably consistent with the functional studies and identify a molecular basis for Ba(2+) blockade of K(+) channels.


    Organizational Affiliation

    Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou 310058, China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calcium-gated potassium channel MthK
A
83Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H)Mutation(s): 2 
Gene Names: mthK
Find proteins for O27564 (Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H))
Go to UniProtKB:  O27564
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
A
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.198 
  • Space Group: P 4 21 2
Unit Cell:
Length (Å)Angle (°)
a = 61.005α = 90.00
b = 61.005β = 90.00
c = 44.950γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PHASESphasing
HKL-2000data scaling
HKL-2000data reduction
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-07-09
    Type: Initial release
  • Version 1.1: 2014-12-10
    Type: Database references