Connexin-26 Bound to Calcium

Experimental Data Snapshot

  • Resolution: 3.29 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.279 
  • R-Value Observed: 0.281 

wwPDB Validation   3D Report Full Report

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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: https://doi.org/10.1038/ncomms9770
  • Primary Citation of Related Structures:  
    5ER7, 5ERA

  • 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 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.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Gap junction beta-2 proteinA [auth B],
B [auth A]
226Homo sapiensMutation(s): 3 
Gene Names: GJB2
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for P29033 (Homo sapiens)
Explore P29033 
Go to UniProtKB:  P29033
PHAROS:  P29033
GTEx:  ENSG00000165474 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29033
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.29 Å
  • R-Value Free: 0.318 
  • R-Value Work: 0.279 
  • R-Value Observed: 0.281 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 156.092α = 90
b = 156.092β = 90
c = 160.077γ = 120
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)United StatesRO1 HL048908

Revision History  (Full details and data files)

  • Version 1.0: 2016-01-27
    Type: Initial release
  • Version 1.1: 2019-12-04
    Changes: Author supporting evidence, Derived calculations