Crystal structure of Z. mays CK2alpha in complex with the ATP-competitive inhibitor 4-[(E)-(fluoren-9-ylidenehydrazinylidene)-methyl] benzoate

Experimental Data Snapshot

  • Resolution: 1.24 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.143 
  • R-Value Observed: 0.145 

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Protein kinase CK2 inhibition is associated with the destabilization of HIF-1 alpha in human cancer cells.

Guerra, B.Rasmussen, T.D.Schnitzler, A.Jensen, H.H.Boldyreff, B.S.Miyata, Y.Marcussen, N.Niefind, K.Issinger, O.G.

(2015) Cancer Lett 356: 751-761

  • DOI: https://doi.org/10.1016/j.canlet.2014.10.026
  • Primary Citation of Related Structures:  
    4RLK, 4RLL

  • PubMed Abstract: 

    Screening for protein kinase CK2 inhibitors of the structural diversity compound library (DTP NCI/NIH) led to the discovery of 4-[(E)-(fluoren-9-ylidenehydrazinylidene)-methyl]benzoic acid (E9). E9 induces apoptotic cell death in various cancer cell lines and upon hypoxia, the compound suppresses CK2-catalyzed HSP90/Cdc37 phosphorylation and induces HIF-1α degradation. Furthermore, E9 exerts a strong anti-tumour activity by inducing necrosis in murine xenograft models underlining its potential to be used for cancer treatment in future clinical studies. Crystal structure analysis of human and maize CK2α in complex with E9 reveals unique binding properties of the inhibitor to the enzyme, accounting for its affinity and selectivity.

  • Organizational Affiliation

    Biomedical Research Group, BMB, University of Southern Denmark, Odense, Denmark.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Casein kinase II subunit alpha332Zea maysMutation(s): 0 
Gene Names: ACK2
Find proteins for P28523 (Zea mays)
Explore P28523 
Go to UniProtKB:  P28523
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP28523
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.24 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.143 
  • R-Value Observed: 0.145 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 142.748α = 90
b = 59.683β = 102.96
c = 44.884γ = 90
Software Package:
Software NamePurpose
XDSdata scaling
XDSdata reduction
CORRECTdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-12-17
    Type: Initial release
  • Version 1.1: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description