3OXQ

Crystal Structure of Ca2+/CaM-CaV1.2 pre-IQ/IQ domain complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.241 
  • R-Value Observed: 0.243 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Multiple C-terminal tail Ca(2+)/CaMs regulate Ca(V)1.2 function but do not mediate channel dimerization.

Kim, E.Y.Rumpf, C.H.Van Petegem, F.Arant, R.J.Findeisen, F.Cooley, E.S.Isacoff, E.Y.Minor, D.L.

(2010) EMBO J 29: 3924-3938

  • DOI: https://doi.org/10.1038/emboj.2010.260
  • Primary Citation of Related Structures:  
    3OXQ

  • PubMed Abstract: 

    Interactions between voltage-gated calcium channels (Ca(V)s) and calmodulin (CaM) modulate Ca(V) function. In this study, we report the structure of a Ca(2+)/CaM Ca(V)1.2 C-terminal tail complex that contains two PreIQ helices bridged by two Ca(2+)/CaMs and two Ca(2+)/CaM-IQ domain complexes. Sedimentation equilibrium experiments establish that the complex has a 2:1 Ca(2+)/CaM:C-terminal tail stoichiometry and does not form higher order assemblies. Moreover, subunit-counting experiments demonstrate that in live cell membranes Ca(V)1.2s are monomers. Thus, contrary to previous proposals, the crystallographic dimer lacks physiological relevance. Isothermal titration calorimetry and biochemical experiments show that the two Ca(2+)/CaMs in the complex have different properties. Ca(2+)/CaM bound to the PreIQ C-region is labile, whereas Ca(2+)/CaM bound to the IQ domain is not. Furthermore, neither of lobes of apo-CaM interacts strongly with the PreIQ domain. Electrophysiological studies indicate that the PreIQ C-region has a role in calcium-dependent facilitation. Together, the data show that two Ca(2+)/CaMs can bind the Ca(V)1.2 tail simultaneously and indicate a functional role for Ca(2+)/CaM at the C-region site.


  • Organizational Affiliation

    Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2330, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calmodulin
A, B, C, D
149Homo sapiensMutation(s): 0 
Gene Names: 
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-1C
E, F
78Homo sapiensMutation(s): 0 
Gene Names: CACH2CACN2CACNA1CCACNL1A1calcium channel CaV1.2CCHL1A1
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
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
G [auth A]
H [auth A]
I [auth A]
J [auth A]
K [auth B]
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth B],
L [auth B],
M [auth B],
N [auth C],
O [auth C],
P [auth C],
Q [auth C],
R [auth D],
S [auth D],
T [auth D]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.241 
  • R-Value Observed: 0.243 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.716α = 90
b = 132.05β = 90
c = 158.222γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-11-03
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description