2GIX

Cytoplasmic Domain Structure of Kir2.1 containing Andersen's Mutation R218Q and Rescue Mutation T309K


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.191 

wwPDB Validation   3D Report Full Report


This is version 1.6 of the entry. See complete history


Literature

Andersen's Syndrome Mutation Effects on the Structure and Assembly of the Cytoplasmic Domains of Kir2.1.

Pegan, S.Arrabit, C.Slesinger, P.A.Choe, S.

(2006) Biochemistry 45: 8599-8606

  • DOI: https://doi.org/10.1021/bi060653d
  • Primary Citation of Related Structures:  
    2GIX

  • PubMed Abstract: 

    Kir2.1 channels play a key role in maintaining the correct resting potential in eukaryotic cells. Recently, specific amino acid mutations in the Kir2.1 inwardly rectifying potassium channel have been found to cause Andersen's Syndrome in humans. Here, we have characterized individual Andersen's Syndrome mutants R218Q, G300V, E303K, and delta314-315 and have found multiple effects on the ability of the cytoplasmic domains in Kir2.1 channels to form proper tetrameric assemblies. For the R218Q mutation, we identified a second site mutation (T309K) that restored tetrameric assembly but not function. We successfully crystallized and solved the structure (at 2.0 A) of the N- and C-terminal cytoplasmic domains of Kir2.1-R218Q/T309K(S). This new structure revealed multiple conformations of the G-loop and CD loop, providing an explanation for channels that assemble but do not conduct ions. Interestingly, Glu303 forms both intra- and intersubunit salt bridges, depending on the conformation of the G-loop, suggesting that the E303K mutant stabilizes both closed and open G-loop conformations. In the Kir2.1-R218Q/T309K(S) structure, we discovered that the DE loop forms a hydrophobic pocket that binds 2-methyl-2,4-pentanediol, which is located near the putative G(betagamma)-activation site of Kir3 channels. Finally, we observed a potassium ion bound to the cytoplasmic domain for this class of K+ channels.


  • Organizational Affiliation

    Structural Biology Laboratory, The Salk Institute, La Jolla, California 92037, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Inward rectifier potassium channel 2
A, B, C, D
208Mus musculusMutation(s): 2 
Gene Names: Kcnj2Irk1
UniProt
Find proteins for P35561 (Mus musculus)
Explore P35561 
Go to UniProtKB:  P35561
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP35561
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.191 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 140.674α = 90
b = 98.876β = 130.68
c = 98.094γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
REFMACrefinement
PDB_EXTRACTdata extraction
Blu-Icedata collection

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-07-25
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-08-16
    Changes: Refinement description, Source and taxonomy
  • Version 1.4: 2017-10-18
    Changes: Refinement description
  • Version 1.5: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.6: 2024-02-14
    Changes: Data collection