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 

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

  • 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 modu ...

    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] Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Small conductance calcium-activated potassium channel protein 2
B
102Rattus norvegicusMutation(s): 0 
Gene Names: Kcnn2
Find proteins for P70604 (Rattus norvegicus)
Go to UniProtKB:  P70604
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Calmodulin
R
149Rattus norvegicusMutation(s): 1 
Gene Names: Calm1 (Calm, Cam, Cam1, CaMI)
Find proteins for P0DP29 (Rattus norvegicus)
Go to UniProtKB:  P0DP29
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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

Download SDF File 
Download 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 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 77.160α = 90.00
b = 65.960β = 93.56
c = 64.680γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
MOSFLMdata reduction
SCALAdata scaling
PHENIXmodel building
PHENIXphasing
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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