Ca2+-bound MthK RCK domain at 1.9 Angstrom with single ligand

Experimental Data Snapshot

  • Resolution: 1.84 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 

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This is version 1.3 of the entry. See complete history


Structural basis of allosteric interactions among Ca(2+)-binding sites in a K(+) channel RCK domain.

Smith, F.J.Pau, V.P.Cingolani, G.Rothberg, B.S.

(2013) Nat Commun 4: 2621-2621

  • DOI: https://doi.org/10.1038/ncomms3621
  • Primary Citation of Related Structures:  
    4L73, 4L74, 4L75, 4L76

  • PubMed Abstract: 

    Ligand binding sites within proteins can interact by allosteric mechanisms to modulate binding affinities and control protein function. Here we present crystal structures of the regulator of K+ conductance (RCK) domain from a K+ channel, MthK, which reveal the structural basis of allosteric coupling between two Ca2+ regulatory sites within the domain. Comparison of RCK domain crystal structures in a range of conformations and with different numbers of regulatory Ca2+ ions bound, combined with complementary electrophysiological analysis of channel gating, suggests chemical interactions that are important for modulation of ligand binding and subsequent channel opening.

  • Organizational Affiliation

    Department of Biochemistry, Temple University School of Medicine, 3400 North Broad Street, Philadelphia, Pennsylvania 19140, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calcium-gated potassium channel MthK
A, B
242Methanothermobacter thermautotrophicus str. Delta HMutation(s): 0 
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: 1.84 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.233α = 90
b = 38.424β = 94.32
c = 96.821γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-10-23
    Type: Initial release
  • Version 1.1: 2013-11-13
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description
  • Version 1.3: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description