Human heat-shock protein 90 (HSP90) in complex with {4-[3-(2,4-dihydroxy-5-isopropyl-phenyl)-5-thioxo- 1,5-dihydro-[1,2,4]triazol-4-yl]-benzyl}-carbamic acid ethyl ester {ZK 2819}

Experimental Data Snapshot

  • Resolution: 1.59 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 

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Ligand Structure Quality Assessment 

This is version 1.3 of the entry. See complete history


Potent triazolothione inhibitor of heat-shock protein-90.

Feldman, R.I.Mintzer, B.Zhu, D.Wu, J.M.Biroc, S.L.Yuan, S.Emayan, K.Chang, Z.Chen, D.Arnaiz, D.O.Bryant, J.Ge, X.S.Whitlow, M.Adler, M.Polokoff, M.A.Li, W.W.Ferrer, M.Sato, T.Gu, J.M.Shen, J.Tseng, J.L.Dinter, H.Buckman, B.

(2009) Chem Biol Drug Des 74: 43-50

  • DOI: https://doi.org/10.1111/j.1747-0285.2009.00833.x
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Heat-shock protein-90 is an attractive target for anticancer drugs, as heat-shock protein-90 blockers such as the ansamycin 17-(allylamino)-17-demethoxygeldanamycin greatly reduce the expression of many signaling molecules that are disregulated in cancer cells and are key drivers of tumor growth and metastasis. While 17-(allylamino)-17-demethoxygeldanamycin has shown promise in clinical trials, this compound class has significant template-related drawbacks. In this paper, we describe a new, potent non-ansamycin small-molecule inhibitor of heat-shock protein-90, BX-2819, containing resorcinol and triazolothione rings. Structural studies demonstrate binding of BX-2819 to the ADP/ATP-binding pocket of heat-shock protein-90. The compound blocked expression of heat-shock protein-90 client proteins in cancer cell lines and inhibited cell growth with a potency similar to 17-(allylamino)-17-demethoxygeldanamycin. In a panel of four cancer cell lines, BX-2819 blocked growth with an average IC(50) value of 32 nM (range of 7-72 nM). Efficacy studies demonstrated that treatment with BX-2819 significantly inhibited the growth of NCI-N87 and HT-29 tumors in nude mice, consistent with pharmacodynamic studies showing inhibition of heat-shock protein-90 client protein expression in tumors for greater than 16 h after dosing. These data support further studies to assess the potential of BX-2819 and related analogs for the treatment of cancer.

  • Organizational Affiliation

    Bayer Healthcare, 2600 Hilltop Drive, Richmond, CA 94804, USA. rick.feldman@bayer.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein HSP 90-alpha
A, B
224Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P07900 (Homo sapiens)
Explore P07900 
Go to UniProtKB:  P07900
PHAROS:  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 819

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
ethyl (4-{3-[2,4-dihydroxy-5-(1-methylethyl)phenyl]-5-sulfanyl-4H-1,2,4-triazol-4-yl}benzyl)carbamate
C21 H24 N4 O4 S
Binding Affinity Annotations 
IDSourceBinding Affinity
819 Binding MOAD:  3HHU IC50: 41 (nM) from 1 assay(s)
PDBBind:  3HHU IC50: 41 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.59 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.019α = 90
b = 90.036β = 90
c = 100.04γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
PDB_EXTRACTdata extraction
BOSdata collection
X-GENdata reduction
X-GENdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-14
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references, Derived calculations