2OGU

Crystal structure of the isolated MthK RCK domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.23 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.235 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Literature

Dynamic oligomeric conversions of the cytoplasmic RCK domains mediate MthK potassium channel activity.

Kuo, M.M.Baker, K.A.Wong, L.Choe, S.

(2007) Proc Natl Acad Sci U S A 104: 2151-2156

  • DOI: https://doi.org/10.1073/pnas.0609085104
  • Primary Citation of Related Structures:  
    2OGU

  • PubMed Abstract: 

    The crystal structure of the RCK-containing MthK provides a molecular framework for understanding the ligand gating mechanisms of K+ channels. Here we examined the macroscopic currents of MthK in enlarged Escherichia coli membrane by patch clamp and rapid perfusion techniques and showed that the channel undergoes desensitization in seconds after activation by Ca2+ or Cd2+. Additionally, MthK is inactivated by slightly acidic pH only from the cytoplasmic side. Examinations of isolated RCK domain by size-exclusion chromatography, static light scattering, analytical sedimentation, and stopped-flow spectroscopy show that Ca2+ rapidly converts isolated RCK monomers to multimers at alkaline pH. In contrast, the RCK domain at acidic pH remains firmly dimeric regardless of Ca2+ but restores predominantly to multimer or monomer at basic pH with or without Ca2+, respectively. These functional and biochemical analyses correlate the four functional states of the MthK channel with distinct oligomeric states of its RCK domains and indicate that the RCK domains undergo oligomeric conversions in modulating MthK activities.


  • Organizational Affiliation

    Structural Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calcium-gated potassium channel mthK233Methanothermobacter thermautotrophicus str. Delta HMutation(s): 0 
Gene Names: mthK
UniProt
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
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.23 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.235 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 165.89α = 90
b = 165.89β = 90
c = 82.22γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
ADSCdata collection
HKL-2000data reduction
SCALEPACKdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-06
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Derived calculations, Source and taxonomy, Version format compliance
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Refinement description