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

Experimental Data Snapshot

  • Resolution: 2.01 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 

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Structure-Guided Evolution of Potent and Selective Chk1 Inhibitors Through Scaffold Morphing.

Reader, J.C.Matthews, T.P.Klair, S.Cheung, K.M.J.Scanlon, J.Proisy, N.Addison, G.Ellard, J.Piton, N.Taylor, S.Cherry, M.Fisher, M.Boxall, K.Burns, S.Walton, M.I.Westwood, I.M.Hayes, A.Eve, P.Valenti, M.De Haven Brandon, A.Box, G.Van Montfort, R.L.M.Williams, D.H.Aherne, G.W.Raynaud, F.I.Eccles, S.A.Garrett, M.D.Collins, I.

(2011) J Med Chem 54: 8328

  • DOI: https://doi.org/10.1021/jm2007326
  • Primary Citation of Related Structures:  
    2YM3, 2YM4, 2YM5, 2YM6, 2YM7, 2YM8

  • PubMed Abstract: 

    Pyrazolopyridine inhibitors with low micromolar potency for CHK1 and good selectivity against CHK2 were previously identified by fragment-based screening. The optimization of the pyrazolopyridines to a series of potent and CHK1-selective isoquinolines demonstrates how fragment-growing and scaffold morphing strategies arising from a structure-based understanding of CHK1 inhibitor binding can be combined to successfully progress fragment-derived hit matter to compounds with activity in vivo. The challenges of improving CHK1 potency and selectivity, addressing synthetic tractability, and achieving novelty in the crowded kinase inhibitor chemical space were tackled by multiple scaffold morphing steps, which progressed through tricyclic pyrimido[2,3-b]azaindoles to N-(pyrazin-2-yl)pyrimidin-4-amines and ultimately to imidazo[4,5-c]pyridines and isoquinolines. A potent and highly selective isoquinoline CHK1 inhibitor (SAR-020106) was identified, which potentiated the efficacies of irinotecan and gemcitabine in SW620 human colon carcinoma xenografts in nude mice.

  • Organizational Affiliation

    Cancer Research UK Cancer Therapeutics Unit and Division of Structural Biology, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, 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
Experimental Data & Validation

Experimental Data

  • Resolution: 2.01 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.05α = 90
b = 65.79β = 94.25
c = 58.14γ = 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: 2012-01-11
    Type: Initial release
  • Version 1.1: 2017-06-28
    Changes: Data collection
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description