Second Ca2+ binding domain of the Na,Ca-exchanger (NCX1)

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


Ca(2+) regulation in the na(+)/ca(2+) exchanger involves two markedly different ca(2+) sensors

Hilge, M.Aelen, J.Vuister, G.W.

(2006) Mol Cell 22: 15-25

  • DOI: https://doi.org/10.1016/j.molcel.2006.03.008
  • Primary Citation of Related Structures:  
    2FWS, 2FWU

  • PubMed Abstract: 

    The plasma membrane Na+/Ca2+ exchanger (NCX) is almost certainly the major Ca2+ extrusion mechanism in cardiac myocytes. Binding of Na+ and Ca2+ ions to its large cytosolic loop regulates ion transport of the exchanger. We determined the solution structures of two Ca2+ binding domains (CBD1 and CBD2) that, together with an alpha-catenin-like domain (CLD), form the regulatory exchanger loop. CBD1 and CBD2 are very similar in the Ca2+ bound state and describe the Calx-beta motif. Strikingly, in the absence of Ca2+, the upper half of CBD1 unfolds while CBD2 maintains its structural integrity. Together with a 7-fold higher affinity for Ca2+, this suggests that CBD1 is the primary Ca2+ sensor. Specific point mutations in either domain largely allow the interchange of their functionality and uncover the mechanism underlying Ca2+ sensing in NCX.

  • Organizational Affiliation

    Department of Biophysical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands. m.hilge@nki.nl

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Sodium/calcium exchanger 1157Canis lupus familiarisMutation(s): 0 
Gene Names: NCX1
Find proteins for P23685 (Canis lupus familiaris)
Explore P23685 
Go to UniProtKB:  P23685
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP23685
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CA

Download Ideal Coordinates CCD File 
B [auth A],
C [auth A]
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-04-18
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-03-09
    Changes: Database references, Derived calculations
  • Version 1.4: 2024-05-29
    Changes: Data collection