2M5E

Structure of the C-domain of Calcium-saturated Calmodulin bound to the IQ motif of NaV1.2


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Calcium triggers reversal of calmodulin on nested anti-parallel sites in the IQ motif of the neuronal voltage-dependent sodium channel NaV1.2.

Hovey, L.Fowler, C.A.Mahling, R.Lin, Z.Miller, M.S.Marx, D.C.Yoder, J.B.Kim, E.H.Tefft, K.M.Waite, B.C.Feldkamp, M.D.Yu, L.Shea, M.A.

(2017) Biophys. Chem. 224: 1-19

  • DOI: 10.1016/j.bpc.2017.02.006

  • PubMed Abstract: 
  • Several members of the voltage-gated sodium channel family are regulated by calmodulin (CaM) and ionic calcium. The neuronal voltage-gated sodium channel NaV1.2 contains binding sites for both apo (calcium-depleted) and calcium-saturated CaM. We have ...

    Several members of the voltage-gated sodium channel family are regulated by calmodulin (CaM) and ionic calcium. The neuronal voltage-gated sodium channel NaV1.2 contains binding sites for both apo (calcium-depleted) and calcium-saturated CaM. We have determined equilibrium dissociation constants for rat NaV1.2 IQ motif [IQRAYRRYLLK] binding to apo CaM (~3nM) and (Ca2+)4-CaM (~85nM), showing that apo CaM binding is favored by 30-fold. For both apo and (Ca2+)4-CaM, NMR demonstrated that NaV1.2 IQ motif peptide (NaV1.2IQp) exclusively made contacts with C-domain residues of CaM (CaMC). To understand how calcium triggers conformational change at the CaM-IQ interface, we determined a solution structure (2M5E.pdb) of (Ca2+)2-CaMC bound to NaV1.2IQp. The polarity of (Ca2+)2-CaMC relative to the IQ motif was opposite to that seen in apo CaMC-Nav1.2IQp (2KXW), revealing that CaMC recognizes nested, anti-parallel sites in Nav1.2IQp. Reversal of CaM may require transient release from the IQ motif during calcium binding, and facilitate a re-orientation of CaMN allowing interactions with non-IQ NaV1.2 residues or auxiliary regulatory proteins interacting in the vicinity of the IQ motif.


    Related Citations: 
    • Structural and Energetic Determinants of Apo Calmodulin Binding to the IQ Motif of the NaV1.2 Voltage-Dependent Sodium Channel
      Feldkamp, M.D.,Yu, L.,Shea, M.A.
      (2011) Structure 19: 733


    Organizational Affiliation

    Department of Biochemistry, University of Iowa, 52242-1109 Iowa City, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calmodulin
A
73Paramecium tetraureliaGene Names: CAM
Find proteins for P07463 (Paramecium tetraurelia)
Go to UniProtKB:  P07463
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Sodium channel protein type 2 subunit alpha
B
27Rattus norvegicusGene Names: Scn2a (Scn2a1)
Find proteins for P04775 (Rattus norvegicus)
Go to UniProtKB:  P04775
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-07-23
    Type: Initial release
  • Version 1.1: 2017-04-19
    Type: Database references