Macromolecule Content

• Total Structure Weight: 15.24 kDa 
• Atom Count: 1068 
• Modelled Residue Count: 139 
• Deposited Residue Count: 139 
• Unique protein chains: 1

2FWS

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

• DOI: 10.2210/pdb2FWS/pdb
• BMRB: 7009

• Classification: METAL TRANSPORT REGULATOR
• Organism(s): Canis lupus familiaris
• Expression System: Escherichia coli BL21
• Mutation(s): No 


• Deposited: 2006-02-03 Released: 2006-04-18 
• Deposition Author(s): Hilge, M., Aelen, J., Vuister, G.W.

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Experimental Data Snapshot

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

Literature

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

• PubMed: 16600866 
• DOI: 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.

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Organizational Affiliation: 

Department of Biophysical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands. [e-mail]

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Sodium/calcium exchanger 1	A	139	Canis lupus familiaris	Mutation(s): 0  Gene Names: NCX1, SLC8A1
UniProt
Find proteins for P23685 (Canis lupus familiaris) Explore P23685  Go to UniProtKB:  P23685

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	B [auth A], C [auth A]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 100 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 
• OLDERADO: 2FWS Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2006-02-03 
• Released Date: 2006-04-18 
Deposition Author(s): Hilge, M., Aelen, J., Vuister, G.W.

Revision History  

• 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