3PE1

Crystal structure of human protein kinase CK2 alpha subunit in complex with the inhibitor CX-4945


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.160 
  • R-Value Observed: 0.162 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Unprecedented selectivity and structural determinants of a new class of protein kinase CK2 inhibitors in clinical trials for the treatment of cancer.

Battistutta, R.Cozza, G.Pierre, F.Papinutto, E.Lolli, G.Sarno, S.O'Brien, S.E.Siddiqui-Jain, A.Haddach, M.Anderes, K.Ryckman, D.M.Meggio, F.Pinna, L.A.

(2011) Biochemistry 50: 8478-8488

  • DOI: 10.1021/bi2008382
  • Primary Citation of Related Structures:  
    3R0T, 3PE1, 3PE2

  • PubMed Abstract: 
  • 5-(3-Chlorophenylamino)benzo[c][2,6]naphthyridine-8-carboxylic acid (CX-4945), the first clinical stage inhibitor of protein kinase CK2 for the treatment of cancer, is representative of a new class of CK2 inhibitors with K(i) values in the low nanomolar range and unprecedented selectivity versus other kinases ...

    5-(3-Chlorophenylamino)benzo[c][2,6]naphthyridine-8-carboxylic acid (CX-4945), the first clinical stage inhibitor of protein kinase CK2 for the treatment of cancer, is representative of a new class of CK2 inhibitors with K(i) values in the low nanomolar range and unprecedented selectivity versus other kinases. Here we present the crystal structure of the complexes of CX-4945 and two analogues (CX-5011 and CX-5279) with the catalytic subunit of human CK2. Consistent with their ATP-competitive mode of inhibition, all three compounds bind in the active site of CK2 (type I inhibitors). The tricyclic scaffold of the inhibitors superposes on the adenine of ATP, establishing multiple hydrophobic interactions with the binding cavity. The more extended scaffold, as compared to that of ATP, allows the carboxylic function, shared by all three ligands, to penetrate into the deepest part of the active site where it makes interactions with conserved water W1 and Lys-68, thus accounting for the crucial role of this negatively charged group in conferring high potency to this class of inhibitors. The presence of a pyrimidine in CX-5011 and in CX-5279 instead of a pyridine (as in CX-4945) ring is likely to account for the higher specificity of these compounds whose Gini coefficients, calculated by profiling them against panels of 102 and/or 235 kinases, are significantly higher than that of CX-4945 (0.735 and 0.755, respectively, vs 0.615), marking the highest selectivity ever reported for CK2 inhibitors.


    Related Citations: 
    • Quinalizarin as a potent, selective and cell-permeable inhibitor of protein kinase CK2.
      Cozza, G., Mazzorana, M., Papinutto, E., Bain, J., Elliott, M., di Maira, G., Gianoncelli, A., Pagano, M.A., Sarno, S., Ruzzene, M., Battistutta, R., Meggio, F., Moro, S., Zagotto, G., Pinna, L.A.
      (2009) Biochem J 421: 387

    Organizational Affiliation

    Venetian Institute of Molecular Medicine, Via G. Orus 2, 35129 Padova, Italy. roberto.battistutta@unipd.it



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Casein kinase II subunit alphaA337Homo sapiensMutation(s): 0 
Gene Names: CSNK2A1CK2A1
EC: 2.7.11.1
Find proteins for P68400 (Homo sapiens)
Explore P68400 
Go to UniProtKB:  P68400
NIH Common Fund Data Resources
PHAROS:  P68400
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
3NG
Query on 3NG

Download Ideal Coordinates CCD File 
B [auth A]5-[(3-chlorophenyl)amino]benzo[c][2,6]naphthyridine-8-carboxylic acid
C19 H12 Cl N3 O2
MUOKSQABCJCOPU-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
C [auth A], D [auth A], E [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
3NGIC50:  0.5   nM  BindingDB
3NGIC50:  2   nM  BindingDB
3NGIC50:  11   nM  BindingDB
3NGIC50:  100   nM  BindingDB
3NGKi:  0.22300000488758087   nM  Binding MOAD
3NGIC50:  1   nM  BindingDB
3NGKd:  0.5600000023841858   nM  BindingDB
3NGIC50:  15   nM  BindingDB
3NGIC50:  20   nM  BindingDB
3NGKi :  0.22300000488758087   nM  PDBBind
3NGIC50:  19   nM  BindingDB
3NGKi:  0.2199999988079071   nM  BindingDB
3NGIC50:  3   nM  BindingDB
3NGIC50:  0.30000001192092896   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.160 
  • R-Value Observed: 0.162 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.478α = 90
b = 46.087β = 111.59
c = 63.493γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
Elettradata collection
XDSdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-09-07
    Type: Initial release
  • Version 1.1: 2012-01-04
    Changes: Database references