2LQC

NMR solution structure of a Ca2+-Calmodulin with a binding motif (NSCaTE) peptide from the N-terminal cytoplasmic domain of the L-type Voltage-Cated Calcium Channel alpha1C subunit


Experimental Data Snapshot

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

wwPDB Validation   3D Report Full Report


This is version 1.0 of the entry. See complete history


Literature

Structural basis for the regulation of L-type voltage-gated calcium channels: interactions between the N-terminal cytoplasmic domain and Ca(2+)-calmodulin.

Liu, Z.Vogel, H.J.

(2012) Front Mol Neurosci 5: 38-38

  • DOI: https://doi.org/10.3389/fnmol.2012.00038
  • Primary Citation of Related Structures:  
    2LQC, 2LQP

  • PubMed Abstract: 

    It is well-known that the opening of L-type voltage-gated calcium channels can be regulated by calmodulin (CaM). One of the main regulatory mechanisms is calcium-dependent inactivation (CDI), where binding of apo-CaM to the cytoplasmic C-terminal domain of the channel can effectively sense an increase in the local calcium ion concentration. Calcium-bound CaM can bind to the IQ-motif region of the C-terminal region and block the calcium channel, thereby providing a negative feedback mechanism that prevents the rise of cellular calcium concentrations over physiological limits. Recently, an additional Ca(2+)/CaM-binding motif (NSCaTE, N-terminal spatial Ca(2+) transforming element) was identified in the amino terminal cytoplasmic region of Ca(v)1.2 and Ca(v)1.3. This motif exists only in Ca(v)1.2 and Ca(v)1.3 channels, and a pronounced N-lobe (Ca(2+)/CaM) CDI effect was found for Ca(v)1.3. To understand the molecular basis of this interaction, the complexes of Ca(2+)/CaM with the biosynthetically produced N-terminal region (residues 1-68) and NSCaTE peptide (residues 48-68) were investigated. We discovered that the NSCaTE motif in the N-terminal cytoplasmic region adopts an α-helical conformation, most likely due to its high alanine content. Additionally, the complex exhibits an unusual 1:2 protein:peptide stoichiometry when bound to Ca(2+)-CaM, and the N-lobe of CaM has a much stronger affinity for the peptide than the C-lobe. The complex structures of the isolated N- and C-lobe of Ca(2+)/CaM and the NSCaTE peptide were determined by nuclear magnetic resonance spectroscopy and data-driven protein-docking methods. Moreover, we also demonstrated that calcium binding protein 1, which competes with CaM for binding to the C-terminal cytoplasmic domain, binds only weakly to the NSCaTE region. The structures provide insights into the possible roles of this motif in the calcium regulatory network. Our study provides structural evidence for the CaM-bridge model proposed in previous studies.


  • Organizational Affiliation

    Department of Biological Sciences, University of Calgary, Calgary AB, Canada.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calmodulin77Homo sapiensMutation(s): 0 
Gene Names: 
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3...
CALM1CALMCAMCAM1CALM2CAM2CAMBCALM3CALML2CAM3CAMCCAMIII

UniProt & NIH Common Fund Data Resources
Find proteins for P0DP23 (Homo sapiens)
Explore P0DP23 
Go to UniProtKB:  P0DP23
PHAROS:  P0DP23
GTEx:  ENSG00000198668 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DP23
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Voltage-dependent L-type calcium channel subunit alpha-1C24Homo sapiensMutation(s): 0 
Gene Names: CACNA1CCACH2CACN2CACNL1A1CCHL1A1
UniProt & NIH Common Fund Data Resources
Find proteins for Q13936 (Homo sapiens)
Explore Q13936 
Go to UniProtKB:  Q13936
PHAROS:  Q13936
GTEx:  ENSG00000151067 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ13936
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

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

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Released Date: 2012-06-06 
  • Deposition Author(s): Liu, Z.

Revision History  (Full details and data files)

  • Version 1.0: 2012-06-06
    Type: Initial release