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 

wwPDB Validation 3D Report Full Report


This is version 1.1 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: 10.1038/emboj.2010.260

  • 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+)/C ...

    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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calmodulin
A, B, C, D
149Homo sapiensMutation(s): 0 
Gene Names: CALM1 (CALM, CAM, CAM1)
Find proteins for P0DP23 (Homo sapiens)
Go to Gene View: CALM1
Go to UniProtKB:  P0DP23
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Voltage-dependent L-type calcium channel subunit alpha-1C
E, F
78Homo sapiensMutation(s): 0 
Gene Names: CACNA1C (CACH2, CACN2, CACNL1A1, CCHL1A1)
Find proteins for Q13936 (Homo sapiens)
Go to Gene View: CACNA1C
Go to UniProtKB:  Q13936
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.241 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 39.716α = 90.00
b = 132.050β = 90.00
c = 158.222γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
HKL-2000data reduction
HKL-2000data collection
SCALEPACKdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-11-03
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance