4QNH

Calcium-calmodulin (T79D) complexed with the calmodulin binding domain from a small conductance potassium channel SK2-a


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.184 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Selective phosphorylation modulates the PIP2 sensitivity of the CaM-SK channel complex.

Zhang, M.Meng, X.Y.Cui, M.Pascal, J.M.Logothetis, D.E.Zhang, J.F.

(2014) Nat Chem Biol 10: 753-759

  • DOI: 10.1038/nchembio.1592
  • Primary Citation of Related Structures:  
    4QNH

  • PubMed Abstract: 
  • Phosphatidylinositol bisphosphate (PIP2) regulates the activities of many membrane proteins, including ion channels, through direct interactions. However, the affinity of PIP2 is so high for some channel proteins that its physiological role as a modulato ...

    Phosphatidylinositol bisphosphate (PIP2) regulates the activities of many membrane proteins, including ion channels, through direct interactions. However, the affinity of PIP2 is so high for some channel proteins that its physiological role as a modulator has been questioned. Here we show that PIP2 is a key cofactor for activation of small conductance Ca2+-activated potassium channels (SKs) by Ca(2+)-bound calmodulin (CaM). Removal of the endogenous PIP2 inhibits SKs. The PIP2-binding site resides at the interface of CaM and the SK C terminus. We further demonstrate that the affinity of PIP2 for its target proteins can be regulated by cellular signaling. Phosphorylation of CaM T79, located adjacent to the PIP2-binding site, by casein kinase 2 reduces the affinity of PIP2 for the CaM-SK channel complex by altering the dynamic interactions among amino acid residues surrounding the PIP2-binding site. This effect of CaM phosphorylation promotes greater channel inhibition by G protein-mediated hydrolysis of PIP2.


    Organizational Affiliation

    1] Department of Molecular Physiology and Biophysics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. [2] Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA. [3] Graduate Program in Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Small conductance calcium-activated potassium channel protein 2 B102Rattus norvegicusMutation(s): 0 
Gene Names: Kcnn2
Find proteins for P70604 (Rattus norvegicus)
Explore P70604 
Go to UniProtKB:  P70604
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Calmodulin R149Rattus norvegicusMutation(s): 1 
Gene Names: 
Calm1CalmCamCam1Calm2Cam2CambCalm3Cam3Camc...
Calm1CalmCamCam1Calm2Cam2CambCalm3Cam3CamcCaMIII

Find proteins for P0DP31 (Rattus norvegicus)
Explore P0DP31 
Go to UniProtKB:  P0DP31
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download Ideal Coordinates CCD File 
B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

Download Ideal Coordinates CCD File 
R
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.02 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.184 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.16α = 90
b = 65.96β = 93.56
c = 64.68γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHENIXmodel building
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling
PHENIXphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-08-06
    Type: Initial release
  • Version 1.1: 2014-09-03
    Changes: Database references