Crystal Structure of Cytoplasmic Domains of IRK1 (Kir2.1) channel

Experimental Data Snapshot

  • Resolution: 2.41 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.225 

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Cytoplasmic domain structures of Kir2.1 and Kir3.1 show sites for modulating gating and rectification

Pegan, S.Arrabit, C.Zhou, W.Kwiatkowski, W.Collins, A.Slesinger, P.A.Choe, S.

(2005) Nat Neurosci 8: 279-287

  • DOI: https://doi.org/10.1038/nn1411
  • Primary Citation of Related Structures:  
    1U4E, 1U4F

  • PubMed Abstract: 

    N- and C-terminal cytoplasmic domains of inwardly rectifying K (Kir) channels control the ion-permeation pathway through diverse interactions with small molecules and protein ligands in the cytoplasm. Two new crystal structures of the cytoplasmic domains of Kir2.1 (Kir2.1(L)) and the G protein-sensitive Kir3.1 (Kir3.1(S)) channels in the absence of PIP(2) show the cytoplasmic ion-permeation pathways occluded by four cytoplasmic loops that form a girdle around the central pore (G-loop). Significant flexibility of the pore-facing G-loop of Kir2.1(L) and Kir3.1(S) suggests a possible role as a diffusion barrier between cytoplasmic and transmembrane pores. Consistent with this, mutations of the G-loop disrupted gating or inward rectification. Structural comparison shows a di-aspartate cluster on the distal end of the cytoplasmic pore of Kir2.1(L) that is important for modulating inward rectification. Taken together, these results suggest the cytoplasmic domains of Kir channels undergo structural changes to modulate gating and inward rectification.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Inward rectifier potassium channel 2
A, B, C, D
270Mus musculusMutation(s): 0 
Gene Names: Kcnj2Irk1
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
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.41 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.225 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.461α = 90
b = 138.294β = 90
c = 138.745γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-03-08
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2013-03-06
    Changes: Other
  • Version 1.4: 2017-08-23
    Changes: Refinement description, Source and taxonomy
  • Version 1.5: 2023-08-23
    Changes: Data collection, Database references, Refinement description