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 

wwPDB Validation   3D Report Full Report


This is version 1.3 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: https://doi.org/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 1.7 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
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CalmodulinA,
C [auth B]
148Drosophila melanogasterMutation(s): 0 
UniProt
Find proteins for P62152 (Drosophila melanogaster)
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Go to UniProtKB:  P62152
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UniProt GroupP62152
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains Sequence 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
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ63450
Sequence Annotations
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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
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations