3SC1

Novel Isoquinolone PDK1 Inhibitors Discovered through Fragment-Based Lead Discovery


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 

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Ligand Structure Quality Assessment 


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Literature

Novel isoquinolone PDK1 inhibitors discovered through fragment-based lead discovery.

Johnson, M.C.Hu, Q.Lingardo, L.Ferre, R.A.Greasley, S.Yan, J.Kath, J.Chen, P.Ermolieff, J.Alton, G.

(2011) J Comput Aided Mol Des 25: 689-698

  • DOI: 10.1007/s10822-011-9456-7
  • Primary Citation of Related Structures:  
    3SC1

  • PubMed Abstract: 
  • Phosphoinositide-dependent kinase-1 (PDK1) is a critical enzyme in the PI3K/AKT pathway and to the activation of AGC family protein kinases, including S6K, SGK, and PKC. Dysregulation of this pathway plays a key role in cancer cell growth, survival and tumor angiogenesis ...

    Phosphoinositide-dependent kinase-1 (PDK1) is a critical enzyme in the PI3K/AKT pathway and to the activation of AGC family protein kinases, including S6K, SGK, and PKC. Dysregulation of this pathway plays a key role in cancer cell growth, survival and tumor angiogenesis. As such, inhibitors of PDK1 offer the promise of a new therapeutic modality for cancer treatment. Fragment based drug screening has recently become a viable entry point for hit identification. In this work, NMR spectroscopy fragment screening of PDK1 afforded novel chemotypes as orthogonal starting points from HTS screening hits. Compounds identified as hits by NMR spectroscopy were tested in a biochemical assay, and fragments with activity in both assays were clustered. The Pfizer compound file was mined via substructure and 2D similarity search, and the chemotypes were prioritized by ligand efficiency (LE), SAR mining, chemical attractiveness, and chemical enablement of promising vectors. From this effort, an isoquinolone fragment hit, 5 (IC(50) 870 μM, LE = 0.39), was identified as a novel, ligand efficient inhibitor of PDK1 and a suitable scaffold for further optimization. Initially in the absence of crystallographic data, a fragment growing approach efficiently explored four vectors of the isoquinolone scaffold via parallel synthesis to afford a compound with crystallographic data, 16 (IC(50) 41.4 μM, LE = 0.33). Subsequent lead optimization efforts provided 24 (IC(50) 1.8 μM, LE = 0.42), with greater than fivefold selectivity against other key pathway kinases.


    Organizational Affiliation

    Pfizer Global Research and Development, San Diego, CA 92121, USA, mcjohnson@inchemdesign.com



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
3-phosphoinositide-dependent protein kinase 1A311Homo sapiensMutation(s): 0 
Gene Names: PDPK1PDK1
EC: 2.7.11.1
UniProt & NIH Common Fund Data Resources
Find proteins for O15530 (Homo sapiens)
Explore O15530 
Go to UniProtKB:  O15530
PHAROS:  O15530
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
SEP
Query on SEP
AL-PEPTIDE LINKINGC3 H8 N O6 PSER
Binding Affinity Annotations 
IDSourceBinding Affinity
3S1 PDBBind:  3SC1 IC50: 4.14e+4 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 123.707α = 90
b = 123.707β = 90
c = 47.295γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
REFMACrefinement
ARPmodel building
WARPmodel building
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
REFMACphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-10-26
    Type: Initial release
  • Version 1.1: 2017-11-08
    Changes: Refinement description