Crystal structure of maize CK2 in complex with NBC (Z1)

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.172 

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Structural features underlying the selectivity of the kinase inhibitors NBC and dNBC: role of a nitro group that discriminates between CK2 and DYRK1A

Sarno, S.Mazzorana, M.Traynor, R.Ruzzene, M.Cozza, G.Pagano, M.A.Meggio, F.Zagotto, G.Battistutta, R.Pinna, L.A.

(2012) Cell Mol Life Sci 69: 449-460

  • DOI: https://doi.org/10.1007/s00018-011-0758-7
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    8-hydroxy-4-methyl-9-nitrobenzo(g)chromen-2-one (NBC) has been found to be a fairly potent ATP site-directed inhibitor of protein kinase CK2 (Ki = 0.22 μM). Here, we show that NBC also inhibits PIM kinases, especially PIM1 and PIM3, the latter as potently as CK2. Upon removal of the nitro group, to give 8-hydroxy-4-methyl-benzo(g)chromen-2-one (here referred to as "denitro NBC", dNBC), the inhibitory power toward CK2 is almost entirely lost (IC(50) > 30 μM) whereas that toward PIM1 and PIM3 is maintained; in addition, dNBC is a potent inhibitor of a number of other kinases that are weakly inhibited or unaffected by NBC, with special reference to DYRK1A whose IC(50) values with NBC and dNBC are 15 and 0.60 μM, respectively. Therefore, the observation that NBC, unlike dNBC, is a potent inducer of apoptosis is consistent with the notion that this effect is mediated by inhibition of endogenous CK2. The structural features underlying NBC selectivity have been revealed by inspecting its 3D structure in complex with the catalytic subunit of Z. mays CK2. The crucial role of the nitro group is exerted both through a direct electrostatic interaction with the side chain of Lys68 and, indirectly, by enhancing the acidic dissociation constant of the adjacent hydroxyl group which interacts with a conserved water molecule in the deepest part of the cavity. By contrast, the very same nitro group is deleterious for the binding to the active site of DYRK1A, as disclosed by molecular docking. This provides the rationale for preferential inhibition of DYRK1A by dNBC.

  • Organizational Affiliation

    Department of Biological Chemistry, University of Padua, V.le G. Colombo 3, 35131 Padua, Italy.

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
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CZ0

Download Ideal Coordinates CCD File 
B [auth A]8-hydroxy-4-methyl-9-nitro-2H-benzo[g]chromen-2-one
C14 H9 N O5
Binding Affinity Annotations 
IDSourceBinding Affinity
CZ0 PDBBind:  3PWD Ki: 220 (nM) from 1 assay(s)
Binding MOAD:  3PWD Ki: 220 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.172 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 142.41α = 90
b = 60.96β = 100.19
c = 45.66γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-11-02
    Type: Initial release
  • Version 1.1: 2013-06-26
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Refinement description