Discovery of Benzisoxazoles as Potent Inhibitors of Chaperone Hsp90

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.194 

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Ligand Structure Quality Assessment 

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Discovery of benzisoxazoles as potent inhibitors of chaperone heat shock protein 90.

Gopalsamy, A.Shi, M.Golas, J.Vogan, E.Jacob, J.Johnson, M.Lee, F.Nilakantan, R.Petersen, R.Svenson, K.Chopra, R.Tam, M.S.Wen, Y.Ellingboe, J.Arndt, K.Boschelli, F.

(2008) J Med Chem 51: 373-375

  • DOI: https://doi.org/10.1021/jm701385c
  • Primary Citation of Related Structures:  
    3BM9, 3BMY

  • PubMed Abstract: 

    Heat shock protein 90 (Hsp90) is a molecular chaperone that is responsible for activating many signaling proteins and is a promising target in tumor biology. We have identified small-molecule benzisoxazole derivatives as Hsp90 inhibitors. Crystallographic studies show that these compounds bind in the ATP binding pocket interacting with the Asp93. Structure based optimization led to the identification of potent analogues, such as 13, with good biochemical profiles.

  • Organizational Affiliation

    Chemical and Screening Sciences, Wyeth Research, Pearl River, NY 10965, USA. gopalsa@wyeth.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein HSP 90-alpha226Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P07900 (Homo sapiens)
Explore P07900 
Go to UniProtKB:  P07900
GTEx:  ENSG00000080824 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07900
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CXZ

Download Ideal Coordinates CCD File 
B [auth A]4-chloro-6-{5-[(2-morpholin-4-ylethyl)amino]-1,2-benzisoxazol-3-yl}benzene-1,3-diol
C19 H20 Cl N3 O4
Binding Affinity Annotations 
IDSourceBinding Affinity
CXZ PDBBind:  3BMY IC50: 30 (nM) from 1 assay(s)
BindingDB:  3BMY IC50: min: 30, max: 30 (nM) from 2 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.194 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.721α = 90
b = 42.462β = 102.22
c = 54.333γ = 90
Software Package:
Software NamePurpose
SERGUIdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2008-07-08
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2020-04-15
    Changes: Data collection, Database references, Source and taxonomy
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references, Derived calculations