X-RAY Crystal structure of compound 39 bound to human chk1 kinase domain

Experimental Data Snapshot

  • Resolution: 1.70 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 

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Ligand Structure Quality Assessment 

This is version 1.2 of the entry. See complete history


Structure-based design and optimization of 2-aminothiazole-4-carboxamide as a new class of CHK1 inhibitors.

Huang, X.Cheng, C.C.Fischmann, T.O.Duca, J.S.Richards, M.Tadikonda, P.K.Reddy, P.A.Zhao, L.Arshad Siddiqui, M.Parry, D.Davis, N.Seghezzi, W.Wiswell, D.Shipps, G.W.

(2013) Bioorg Med Chem Lett 23: 2590-2594

  • DOI: https://doi.org/10.1016/j.bmcl.2013.02.108
  • Primary Citation of Related Structures:  
    4HYH, 4HYI

  • PubMed Abstract: 

    Drug design efforts in the emerging 2-aminothiazole-4-carboxamide class of CHK1 inhibitors have uncovered specific combinations of key substructures within the molecule; resulting in significant improvements in cell-based activity while retaining a greater than one hundred-fold selectivity against CDK2. The X-ray crystal structure of a complex between compound 39 and the CHK1 protein detailing a 'U-shaped' topology and key interactions with the protein surface at the ATP site is also reported.

  • Organizational Affiliation

    Merck Research Laboratories, 320 Bent Street, Cambridge, MA 02141, USA. xiaohua.huang@merck.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Serine/threonine-protein kinase Chk1289Homo sapiensMutation(s): 0 
Gene Names: CHEK1CHK1
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 1AM

Download Ideal Coordinates CCD File 
B [auth A]2-(6-methoxy-1-oxo-1,3-dihydro-2H-isoindol-2-yl)-N-[4-(piperazin-1-yl)pyridin-3-yl]-1,3-thiazole-4-carboxamide
C22 H22 N6 O3 S
Binding Affinity Annotations 
IDSourceBinding Affinity
1AM PDBBind:  4HYH IC50: 1 (nM) from 1 assay(s)
BindingDB:  4HYH IC50: min: 1, max: 3.7 (nM) from 2 assay(s)
EC50: 30 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.70 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.97α = 90
b = 65.96β = 102.39
c = 54.42γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-06
    Type: Initial release
  • Version 1.1: 2013-05-01
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references, Derived calculations