4I9W

Human two pore domain K+ channel TRAAK (K2P4.1) - Fab complex structure


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.201 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Domain-swapped chain connectivity and gated membrane access in a Fab-mediated crystal of the human TRAAK K+ channel.

Brohawn, S.G.Campbell, E.B.Mackinnon, R.

(2013) Proc.Natl.Acad.Sci.USA 110: 2129-2134

  • DOI: 10.1073/pnas.1218950110

  • PubMed Abstract: 
  • TRAAK (TWIK-related arachidonic acid-stimulated K(+) channel, K2P4.1) K(+) ion channels are expressed predominantly in the nervous system to control cellular resting membrane potential and are regulated by mechanical and chemical properties of the li ...

    TRAAK (TWIK-related arachidonic acid-stimulated K(+) channel, K2P4.1) K(+) ion channels are expressed predominantly in the nervous system to control cellular resting membrane potential and are regulated by mechanical and chemical properties of the lipid membrane. TRAAK channels are twofold symmetric, which precludes a direct extension of gating mechanisms that close canonical fourfold symmetric K(+) channels. We present the crystal structure of human TRAAK in complex with antibody antigen-binding fragments (Fabs) at 2.75-Å resolution. In contrast to a previous structure, this structure reveals a domain-swapped chain connectivity enabled by the helical cap that exchanges two opposing outer helices 180° around the channel. An unrelated conformational change of an inner helix seals a side opening to the membrane bilayer and is associated with structural changes around the K(+)-selectivity filter that may have implications for mechanosensitivity and gating of TRAAK channels.


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Potassium channel subfamily K member 4
A, B
309Homo sapiensGene Names: KCNK4 (TRAAK)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Potassium, Sodium, & Proton Ion-Selective
Protein: 
Two-Pore Domain Potassium Channel K2P4.1 (TRAAK)
Find proteins for Q9NYG8 (Homo sapiens)
Go to Gene View: KCNK4
Go to UniProtKB:  Q9NYG8
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ANTIBODY FAB FRAGMENT LIGHT CHAIN
D, F
211N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
ANTIBODY FAB FRAGMENT HEAVY CHAIN
E, G
217N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
A, B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
A, G
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.75 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.201 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 80.887α = 90.00
b = 138.905β = 94.87
c = 97.461γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data collection
PHASERphasing
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-01-23
    Type: Initial release
  • Version 1.1: 2013-02-20
    Type: Database references