Structure of human Hsp90-alpha bound to the potent water soluble inhibitor PU-H71

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.190 

Starting Model: experimental
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Structural and quantum chemical studies of 8-aryl-sulfanyl adenine class Hsp90 inhibitors.

Immormino, R.M.Kang, Y.Chiosis, G.Gewirth, D.T.

(2006) J Med Chem 49: 4953-4960

  • DOI: https://doi.org/10.1021/jm060297x
  • Primary Citation of Related Structures:  
    2FWY, 2FWZ, 2H55

  • PubMed Abstract: 

    Hsp90 chaperones play a critical role in modulating the activity of many cell signaling proteins and are an attractive target for anti-cancer therapeutics. We report here the structures of the water soluble 8-aryl-sulfanyl adenine class Hsp90 inhibitors, 1 (PU-H71) and 2 (PU-H64), in complex with the N-terminal domain of human Hsp90alpha. The conformation of 1 when bound to Hsp90 differs from previously reported 8-aryl adenine Hsp90 inhibitors including 3 (PU24FCl). While the binding mode for 3 places the 2'-halide of the 8-aryl group on top of the adenine ring, for 1 and 2, we show that the 2'-halide is rotated approximately 180 degrees away. This difference explains the opposing trends in Hsp90 inhibitory activity for the 2'-halo derivatives of the 3',4',5'-trimethoxy series where Cl > Br > I compared to the 4',5'-methylenedioxy series where I > Br > Cl. We also present quantum chemical calculations of 2 and its analogues that illuminate their basis for Hsp90 inhibition. The calculated conformation of 2 agreed well with the crystallographically observed conformations of 1 and 2. The predictive nature of the calculations has allowed the exploration of additional derivatives based on the 8-aryl adenine scaffold.

  • Organizational Affiliation

    Hauptman-Woodward Medical Research Institute, Buffalo, New York 14203, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein HSP 90-alpha256Homo sapiensMutation(s): 0 
Gene Names: HSPCA
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 H71

Download Ideal Coordinates CCD File 
C18 H21 I N6 O2 S
Binding Affinity Annotations 
IDSourceBinding Affinity
H71 BindingDB:  2FWZ IC50: min: 42, max: 126 (nM) from 8 assay(s)
EC50: min: 10, max: 6000 (nM) from 8 assay(s)
PDBBind:  2FWZ IC50: 50 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.190 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.68α = 90
b = 91.28β = 90
c = 98.64γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
XDSdata 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: 2006-10-03
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description