Crystal structure of the human two pore domain K+ ion channel TRAAK (K2P4.1)

Experimental Data Snapshot

  • Resolution: 3.31 Å
  • R-Value Free: 0.323 
  • R-Value Work: 0.317 
  • R-Value Observed: 0.317 

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Crystal structure of the human K2P TRAAK, a lipid- and mechano-sensitive K+ ion channel.

Brohawn, S.G.del Marmol, J.MacKinnon, R.

(2012) Science 335: 436-441

  • DOI: https://doi.org/10.1126/science.1213808
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    TRAAK channels, members of the two-pore domain K(+) (potassium ion) channel family K2P, are expressed almost exclusively in the nervous system and control the resting membrane potential. Their gating is sensitive to polyunsaturated fatty acids, mechanical deformation of the membrane, and temperature changes. Physiologically, these channels appear to control the noxious input threshold for temperature and pressure sensitivity in dorsal root ganglia neurons. We present the crystal structure of human TRAAK at a resolution of 3.8 angstroms. The channel comprises two protomers, each containing two distinct pore domains, which create a two-fold symmetric K(+) channel. The extracellular surface features a helical cap, 35 angstroms tall, that creates a bifurcated pore entryway and accounts for the insensitivity of two-pore domain K(+) channels to inhibitory toxins. Two diagonally opposed gate-forming inner helices form membrane-interacting structures that may underlie this channel's sensitivity to chemical and mechanical properties of the cell membrane.

  • Organizational Affiliation

    Laboratory of Molecular Neurobiology and Biophysics and Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Potassium channel subfamily K member 4
A, B
309Homo sapiensMutation(s): 2 
Gene Names: KCNK4TRAAK
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for Q9NYG8 (Homo sapiens)
Explore Q9NYG8 
Go to UniProtKB:  Q9NYG8
GTEx:  ENSG00000182450 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9NYG8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.31 Å
  • R-Value Free: 0.323 
  • R-Value Work: 0.317 
  • R-Value Observed: 0.317 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 87.938α = 90
b = 130.852β = 90
c = 132.779γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-02-08
    Type: Initial release