Crystal structure of checkpoint kinase 1 (Chk1) in complex with inhibitors

Experimental Data Snapshot

  • Resolution: 2.70 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Design and Evaluation of 3,6-Di(Hetero)Aryl Imidazo[1,2-A]Pyrazines as Inhibitors of Checkpoint and Other Kinases.

Matthews, T.P.Mchardy, T.Klair, S.Boxall, K.Fisher, M.Cherry, M.Allen, C.E.Addison, G.J.Ellard, J.Aherne, G.W.Westwood, I.M.Montfort, R.V.Garrett, M.D.Reader, J.C.Collins, I.

(2010) Bioorg Med Chem Lett 20: 4045

  • DOI: https://doi.org/10.1016/j.bmcl.2010.05.096
  • Primary Citation of Related Structures:  
    2XEY, 2XEZ, 2XF0

  • PubMed Abstract: 

    A range of 3,6-di(hetero)arylimidazo[1,2-a]pyrazine ATP-competitive inhibitors of CHK1 were developed by scaffold hopping from a weakly active screening hit. Efficient synthetic routes for parallel synthesis were developed to prepare analogues with improved potency and ligand efficiency against CHK1. Kinase profiling showed that the imidazo[1,2-a]pyrazines could inhibit other kinases, including CHK2 and ABL, with equivalent or better potency depending on the pendant substitution. These 3,6-di(hetero)aryl imidazo[1,2-a]pyrazines appear to represent a general kinase inhibitor scaffold.

  • Organizational Affiliation

    Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom. tom.matthews@icr.ac.uk

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SERINE/THREONINE-PROTEIN KINASE CHK1289Homo 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 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on YVQ

Download Ideal Coordinates CCD File 
C17 H12 N6
Binding Affinity Annotations 
IDSourceBinding Affinity
YVQ PDBBind:  2XEY IC50: 6500 (nM) from 1 assay(s)
BindingDB:  2XEY IC50: 6500 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.70 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.97α = 90
b = 65.66β = 93.91
c = 57.96γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2010-06-30
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-06-28
    Changes: Data collection
  • Version 1.4: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description