5ER7

Connexin-26 Bound to Calcium


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.286 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.279 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels.

Bennett, B.C.Purdy, M.D.Baker, K.A.Acharya, C.McIntire, W.E.Stevens, R.C.Zhang, Q.Harris, A.L.Abagyan, R.Yeager, M.

(2016) Nat Commun 7: 8770-8770

  • DOI: 10.1038/ncomms9770
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. To explore the mechanism by which Ca(2+) blocks intercellular communicatio ...

    Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). The two structures were nearly identical, ruling out both a large-scale structural change and a local steric constriction of the pore. Ca(2+) coordination sites reside at the interfaces between adjacent subunits, near the entrance to the extracellular gap, where local, side chain conformational rearrangements enable Ca(2+)chelation. Computational analysis revealed that Ca(2+)-binding generates a positive electrostatic barrier that substantially inhibits permeation of cations such as K(+) into the pore. Our results provide structural evidence for a unique mechanism of channel regulation: ionic conduction block via an electrostatic barrier rather than steric occlusion of the channel pore.


    Related Citations: 
    • Steroid-based facial amphiphiles for stabilization and crystallization of membrane proteins.
      Lee, S.C.,Bennett, B.C.,Hong, W.X.,Fu, Y.,Baker, K.A.,Marcoux, J.,Robinson, C.V.,Ward, A.B.,Halpert, J.R.,Stevens, R.C.,Stout, C.D.,Yeager, M.J.,Zhang, Q.
      (2013) Proc. Natl. Acad. Sci. U.S.A. 110: E1203


    Organizational Affiliation

    Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Gap junction beta-2 protein
B, A
226Homo sapiensMutation(s): 3 
Gene Names: GJB2
Find proteins for P29033 (Homo sapiens)
Go to Gene View: GJB2
Go to UniProtKB:  P29033
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.286 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.279 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 156.092α = 90.00
b = 156.092β = 90.00
c = 160.077γ = 120.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
PHENIXrefinement
HKL-2000data reduction
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health (NHLBI)United StatesRO1 HL048908

Revision History 

  • Version 1.0: 2016-01-27
    Type: Initial release