1QX7

Crystal structure of apoCaM bound to the gating domain of small conductance Ca2+-activated potassium channel

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.09 Å
  • R-Value Free: 0.308 
  • R-Value Work: 0.286 
  • R-Value Observed: 0.286 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history. 


Literature

Crystal structures of apocalmodulin and an apocalmodulin/SK potassium channel gating domain complex.

Schumacher, M.A., Crum, M., Miller, M.C.

(2004) Structure 12: 849-860

  • DOI: 10.1016/j.str.2004.03.017
  • Primary Citation of Related Structures:  
    1QX7, 1QX5

  • PubMed Abstract: 

    • Small conductance Ca2+-activated K+ channels (SK channels) are composed of the pore-forming alpha subunit and calmodulin (CaM). CaM binds to a region of the alpha subunit called the CaM binding domain (CaMBD), located intracellular and immediately C-term ...

    Small conductance Ca2+-activated K+ channels (SK channels) are composed of the pore-forming alpha subunit and calmodulin (CaM). CaM binds to a region of the alpha subunit called the CaM binding domain (CaMBD), located intracellular and immediately C-terminal to the inner helix gate, in either the presence or absence of Ca2+. SK gating occurs when Ca2+ binds the N lobe of CaM thereby transmitting the signal to the attached inner helix gate to open. Here we present crystal structures of apoCaM and apoCaM/SK2 CaMBD complex. Several apoCaM crystal forms with multiple (12) packing environments reveal the same EF hand domain-swapped dimer providing potentially new insight into CaM regulation. The apoCaM/SK2 CaMBD structure, combined with our Ca2+/CaM/CaMBD structure suggests that Ca2+ binding induces folding and dimerization of the CaMBD, which causes large CaMBD-CaM C lobe conformational changes, including a >90 degrees rotation of the region of the CaMBD directly connected to the gate.

    Organizational Affiliation: 

    Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239 USA. schumacm@ohsu.edu



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Calmodulin A, B, I, M, R148Rattus norvegicusMutation(s): 9 
Gene Names: 
Calm1, Cam1, Calm, Cam, CALM2, CAM2, CAMB, CALM3, CAM3, CAMC...
Calm1, Cam1, Calm, Cam, CALM2, CAM2, CAMB, CALM3, CAM3, CAMC, CaMI

Find proteins for P0DP29 (Rattus norvegicus)
Explore P0DP29 
Go to UniProtKB:  P0DP29
Protein Feature View
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  • Reference Sequence
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(by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Small conductance calcium-activated potassium channel protein 2 D85Rattus 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
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE		A,B,I,M,RL-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.09 Å
  • R-Value Free: 0.308 
  • R-Value Work: 0.286 
  • R-Value Observed: 0.286 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.93α = 90
b = 79.93β = 90
c = 220.8γ = 90
Software Package:
Software NamePurpose
CNSrefinement
MOSFLMdata reduction
CCP4data scaling
CNSphasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-08-31
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance