1MXE

Structure of the Complex of Calmodulin with the Target Sequence of CaMKI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 

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This is version 1.2 of the entry. See complete history


Literature

Structure of the Complex of Calmodulin with the Target Sequence of Calmodulin-Dependent Protein Kinase I: Studies of the Kinase Activation Mechanism

Clapperton, J.A.Martin, S.R.Smerdon, S.J.Gamblin, S.J.Bayley, P.M.

(2002) Biochemistry 41: 14669-14679

  • DOI: 10.1021/bi026660t
  • Primary Citation of Related Structures:  
    1MXE

  • PubMed Abstract: 
  • Calcium-saturated calmodulin (CaM) directly activates CaM-dependent protein kinase I (CaMKI) by binding to a region in the C-terminal regulatory sequence of the enzyme to relieve autoinhibition. The structure of CaM in a high-affinity complex with a 25-residue peptide of CaMKI (residues 294-318) has been determined by X-ray crystallography at 1 ...

    Calcium-saturated calmodulin (CaM) directly activates CaM-dependent protein kinase I (CaMKI) by binding to a region in the C-terminal regulatory sequence of the enzyme to relieve autoinhibition. The structure of CaM in a high-affinity complex with a 25-residue peptide of CaMKI (residues 294-318) has been determined by X-ray crystallography at 1.7 A resolution. Upon complex formation, the CaMKI peptide adopts an alpha-helical conformation, while changes in the CaM domain linker enable both its N- and C-domains to wrap around the peptide helix. Target peptide residues Trp-303 (interacting with the CaM C-domain) and Met-316 (with the CaM N-domain) define the mode of binding as 1-14. In addition, two basic patches on the peptide form complementary charge interactions with CaM. The CaM-peptide affinity is approximately 1 pM, compared with 30 nM for the CaM-kinase complex, indicating that activation of autoinhibited CaMKI by CaM requires a costly energetic disruption of the interactions between the CaM-binding sequence and the rest of the enzyme. We present biochemical and structural evidence indicating the involvement of both CaM domains in the activation process: while the C-domain exhibits tight binding toward the regulatory sequence, the N-domain is necessary for activation. Our crystal structure also enables us to identify the full CaM-binding sequence. Residues Lys-296 and Phe-298 from the target peptide interact directly with CaM, demonstrating overlap between the autoinhibitory and CaM-binding sequences. Thus, the kinase activation mechanism involves the binding of CaM to residues associated with the inhibitory pseudosubstrate sequence.


    Organizational Affiliation

    Division of Protein Structure, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CalmodulinA, C [auth B]148Drosophila melanogasterMutation(s): 0 
Gene Names: CamCG8472
UniProt
Find proteins for P62152 (Drosophila melanogaster)
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Go to UniProtKB:  P62152
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Target Sequence of rat Calmodulin-Dependent Protein Kinase IB [auth E], D [auth F]25N/AMutation(s): 0 
EC: 2.7.1.123
UniProt
Find proteins for Q63450 (Rattus norvegicus)
Explore Q63450 
Go to UniProtKB:  Q63450
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.712α = 90
b = 69.581β = 90
c = 75.344γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing
REFMACrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-12-04
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance