Crystal Structure of Chek1 in Complex with Inhibitor 54

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 

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This is version 1.2 of the entry. See complete history


Synthesis and evaluation of substituted benzoisoquinolinones as potent inhibitors of Chk1 kinase.

Garbaccio, R.M.Huang, S.Tasber, E.S.Fraley, M.E.Yan, Y.Munshi, S.Ikuta, M.Kuo, L.Kreatsoulas, C.Stirdivant, S.Drakas, B.Rickert, K.Walsh, E.S.Hamilton, K.A.Buser, C.A.Hardwick, J.Mao, X.Beck, S.C.Abrams, M.T.Tao, W.Lobell, R.Sepp-Lorenzino, L.Hartman, G.D.

(2007) Bioorg Med Chem Lett 17: 6280-6285

  • DOI: https://doi.org/10.1016/j.bmcl.2007.09.007
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    From HTS lead 1, a novel benzoisoquinolinone class of ATP-competitive Chk1 inhibitors was devised and synthesized via a photochemical route. Using X-ray crystallography as a guide, potency was rapidly enhanced through the installation of a tethered basic amine designed to interact with an acidic residue (Glu91) in the enzyme pocket. Further SAR was explored at the solvent front and near to the H1 pocket and resulted in the discovery of low MW, sub-nanomolar inhibitors of Chk1.

  • Organizational Affiliation

    Department of Medicinal Chemistry, Merck Research Laboratories, West Point, PA 19486, USA. robert_garbaccio@merck.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Serine/threonine-protein kinase Chk1323Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for O14757 (Homo sapiens)
Explore O14757 
Go to UniProtKB:  O14757
PHAROS:  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 M54

Download Ideal Coordinates CCD File 
B [auth A]6-(3-aminopropyl)-4-(3-hydroxyphenyl)-9-(1H-pyrazol-4-yl)benzo[h]isoquinolin-1(2H)-one
C25 H22 N4 O2
Binding Affinity Annotations 
IDSourceBinding Affinity
M54 BindingDB:  2R0U IC50: 1 (nM) from 1 assay(s)
PDBBind:  2R0U IC50: 1 (nM) from 1 assay(s)
Binding MOAD:  2R0U IC50: 1 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.26α = 90
b = 65.54β = 94.27
c = 58.5γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
d*TREKdata reduction
d*TREKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-10-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description