Synthesis and evaluation of triazolones as checkpoint kinase 1 inhibitors

Experimental Data Snapshot

  • Resolution: 1.30 Å
  • R-Value Free: 0.164 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.135 

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

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Synthesis and Evaluation of Triazolones as Checkpoint Kinase 1 Inhibitors.

Oza, V.Ashwell, S.Brassil, P.Breed, J.Ezhuthachan, J.Deng, C.Grondine, M.Horn, C.Liu, D.Lyne, P.Newcombe, N.Pass, M.Read, J.Su, M.Toader, D.Yu, D.Yu, Y.Zabludoff, S.

(2012) Bioorg Med Chem Lett 22: 2330

  • DOI: https://doi.org/10.1016/j.bmcl.2012.01.043
  • Primary Citation of Related Structures:  
    2YER, 2YEX

  • PubMed Abstract: 

    Checkpoint kinase 1 (Chk1, CHEK1) is a Ser/Thr protein kinase that plays a key role in mediating the cellular response to DNA-damage. Synthesis and evaluation of a previously described class of Chk1 inhibitors, triazoloquinolones/triazolones (TZs) is further described herein. Our investigation of structure-activity relationships led to the identification of potent inhibitors 14c, 14h and 16e. Key challenges included modulation of physicochemical properties and pharmacokinetic (PK) parameters to enable compound testing in a Chk1 specific hollow fiber pharmacodynamic model. In this model, 16e was shown to abrogate topotecan-induced cell cycle arrest in a dose dependent manner. The demonstrated activity of TZs in this model in combination with a chemotherapeutic agent as well as radiotherapy validates this series of Chk1 inhibitors. X-ray crystal structures (PDB code: 2YEX and 2YER) for an initial lead and an optimized analog are also presented.

  • Organizational Affiliation

    AstraZeneca R&D Boston, 35 Gatehouse Drive, Waltham, MA 02451, USA. Vibha.Oza@astrazeneca.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SERINE/THREONINE-PROTEIN KINASE CHK1276Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for O14757 (Homo sapiens)
Explore O14757 
Go to UniProtKB:  O14757
GTEx:  ENSG00000149554 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO14757
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on YEX

Download Ideal Coordinates CCD File 
I [auth A]5-METHYL-8-(1H-PYRROL-2-YL)[1,2,4]TRIAZOLO[4,3-A]QUINOLIN-1(2H)-ONE
C15 H12 N4 O
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Query on GOL

Download Ideal Coordinates CCD File 
B [auth A]
C [auth A]
D [auth A]
E [auth A]
F [auth A]
B [auth A],
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A]
C3 H8 O3
Binding Affinity Annotations 
IDSourceBinding Affinity
YEX BindingDB:  2YEX IC50: 0.1 (nM) from 1 assay(s)
PDBBind:  2YEX IC50: 0.1 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.30 Å
  • R-Value Free: 0.164 
  • R-Value Work: 0.134 
  • R-Value Observed: 0.135 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.352α = 90
b = 70.77β = 90
c = 104.327γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-03-14
    Type: Initial release
  • Version 1.1: 2024-05-08
    Changes: Data collection, Database references, Derived calculations, Other