Crystal structure of the catalytic subunit of protein kinase CK2 (C-terminal deletion mutant 1-335) in complex with two sulfate ions

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.187 

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Evolved to Be Active: Sulfate Ions Define Substrate Recognition Sites of CK2alpha and Emphasise its Exceptional Role within the CMGC Family of Eukaryotic Protein Kinases

Niefind, K.Yde, C.W.Ermakova, I.Issinger, O.G.

(2007) J Mol Biol 370: 427-438

  • DOI: https://doi.org/10.1016/j.jmb.2007.04.068
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    CK2alpha is the catalytic subunit of protein kinase CK2 and a member of the CMGC family of eukaryotic protein kinases like the cyclin-dependent kinases, the MAP kinases and glycogen-synthase kinase 3. We present here a 1.6 A resolution crystal structure of a fully active C-terminal deletion mutant of human CK2alpha liganded by two sulfate ions, and we compare this structure systematically with representative structures of related CMGC kinases. The two sulfate anions occupy binding pockets at the activation segment and provide the structural basis of the acidic consensus sequence S/T-D/E-X-D/E that governs substrate recognition by CK2. The anion binding sites are conserved among those CMGC kinases. In most cases they are neutralized by phosphorylation of a neighbouring threonine or tyrosine side-chain, which triggers conformational changes for regulatory purposes. CK2alpha, however, lacks both phosphorylation sites at the activation segment and structural plasticity. Here the anion binding sites are functionally changed from regulation to substrate recognition. These findings underline the exceptional role of CK2alpha as a constitutively active enzyme within a family of strictly controlled protein kinases.

  • Organizational Affiliation

    Universität zu Köln, Institut für Biochemie, Zülpicher Strasse 47, D-50674 Köln, Germany. Karsten.Niefind@uni-koeln.de

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Casein kinase II subunit alpha, catalytic subunit334Homo sapiensMutation(s): 0 
Gene Names: CSNK2A1CK2A1
UniProt & NIH Common Fund Data Resources
Find proteins for P68400 (Homo sapiens)
Explore P68400 
Go to UniProtKB:  P68400
PHAROS:  P68400
GTEx:  ENSG00000101266 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68400
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.187 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.67α = 90
b = 45.371β = 111.22
c = 63.442γ = 90
Software Package:
Software NamePurpose
XDSdata scaling
XDSdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-06-26
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description