2L53 | pdb_00002l53

Solution NMR Structure of apo-calmodulin in complex with the IQ motif of Human Cardiac Sodium Channel NaV1.5

• PDB DOI: https://doi.org/10.2210/pdb2L53/pdb
• BMRB: 17264

• Classification: CA-BINDING PROTEIN/PROTON TRANSPORT
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2010-10-24 Released: 2011-01-05 
• Deposition Author(s): Chagot, B., Chazin, W.J.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 200 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Literature

Solution NMR Structure of Apo-Calmodulin in Complex with the IQ Motif of Human Cardiac Sodium Channel NaV1.5.

Chagot, B., Chazin, W.J.

(2011) J Mol Biology 406: 106-119

• PubMed: 21167176 
• DOI: https://doi.org/10.1016/j.jmb.2010.11.046
• Primary Citation Related Structures: 
  2L53


• PubMed Abstract: 
  

  The function of the human voltage-gated sodium channel Na(V)1.5 is regulated in part by intracellular calcium signals. The ubiquitous calcium sensor protein calmodulin (CaM) is an important part of the complex calcium-sensing apparatus in Na(V)1.5. CaM interacts with an IQ (isoleucine-glutamine) motif in the large intracellular C-terminal domain of the channel. Using co-expression and co-purification, we have been able to isolate a CaM-IQ motif complex and to determine its high-resolution structure in absence of calcium using multi-dimensional solution NMR. Under these conditions, the Na(V)1.5 IQ motif interacts with the C-terminal domain (C-lobe) of CaM, with the N-terminal domain remaining free in solution. The structure reveals that the C-lobe adopts a semi-open conformation with the IQ motif bound in a narrow hydrophobic groove. Sequence similarities between voltage-gated sodium channels and voltage-gated calcium channels suggest that the structure of the CaM-Na(V)1.5 IQ motif complex can serve as a general model for the interaction between CaM and ion channel IQ motifs under low-calcium conditions. The structure also provides insight into the biochemical basis for disease-associated mutations that map to the IQ motif in Na(V)1.5.

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Organizational Affiliation: 
• Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 20.25 kDa 
• Atom Count: 1,414 
• Modeled Residue Count: 179 
• Deposited Residue Count: 179 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Calmodulin	A	148	Homo sapiens	Mutation(s): 0  Gene Names:  CALM1, CALM, CAM, CAM1, CALM2, CAM2, CAMB, CALM3, CALML2, CAM3, CAMC, CAMIII

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Voltage-gated sodium channel type V alpha isoform b variant	B	31	Homo sapiens	Mutation(s): 0
UniProt & NIH Common Fund Data Resources
Find proteins for Q14524 (Homo sapiens) Explore Q14524  Go to UniProtKB:  Q14524
PHAROS:  Q14524 GTEx:  ENSG00000183873

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 200 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Structure Validation

Entry History 

Deposition Data

• Released Date: 2011-01-05 
Deposition Author(s): Chagot, B., Chazin, W.J.

Revision History  

• Version 1.0: 2011-01-05
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2024-05-01
  Changes: Data collection, Database references