Hsp90b N-terminal domain in complex with EC44, a pyrrolo-pyrimidine methoxypyridine inhibitor

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.202 

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EC144, a Synthetic Inhibitor of Heat Shock Protein 90, Blocks Innate and Adaptive Immune Responses in Models of Inflammation and Autoimmunity.

Yun, T.J.Harning, E.K.Giza, K.Rabah, D.Li, P.Arndt, J.W.Luchetti, D.Biamonte, M.A.Shi, J.Lundgren, K.Manning, A.Kehry, M.R.

(2011) J Immunol 186: 563-575

  • DOI: https://doi.org/10.4049/jimmunol.1000222
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Heat shock protein 90 (Hsp90) is a molecular chaperone involved in folding and stabilizing multiple intracellular proteins that have roles in cell activation and proliferation. Many Hsp90 client proteins in tumor cells are mutated or overexpressed oncogenic proteins driving cancer cell growth, leading to the acceptance of Hsp90 as a potential therapeutic target for cancer. Because several signal transduction molecules that are dependent on Hsp90 function are also involved in activation of innate and adaptive cells of the immune system, we investigated the mechanism by which inhibiting Hsp90 leads to therapeutic efficacy in rodent models of inflammation and autoimmunity. EC144, a synthetic Hsp90 inhibitor, blocked LPS-induced TLR4 signaling in RAW 264.7 cells by inhibiting activation of ERK1/2, MEK1/2, JNK, and p38 MAPK but not NF-κB. Ex vivo LPS-stimulated CD11b(+) peritoneal exudate cells from EC144-treated mice were blocked from phosphorylating tumor progression locus 2, MEK1/2, and ERK1/2. Consequently, EC144-treated mice were resistant to LPS administration and had suppressed systemic TNF-α release. Inhibiting Hsp90 also blocked in vitro CD4(+) T cell proliferation in mouse and human MLRs. In vivo, semitherapeutic administration of EC144 blocked disease development in rat collagen-induced arthritis by suppressing the inflammatory response. In a mouse collagen-induced arthritis model, EC144 also suppressed disease development, which correlated with a suppressed Ag-specific Ab response and a block in activation of Ag-specific CD4(+) T cells. Our results describe mechanisms by which blocking Hsp90 function may be applicable to treatment of autoimmune diseases involving inflammation and activation of the adaptive immune response.

  • Organizational Affiliation

    Department of Immunobiology, Biogen Idec, San Diego, CA 92122, USA. ted.yun@biogenidec.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein HSP 90-beta239Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P08238 (Homo sapiens)
Explore P08238 
Go to UniProtKB:  P08238
PHAROS:  P08238
GTEx:  ENSG00000096384 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08238
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 7PP

Download Ideal Coordinates CCD File 
B [auth A]5-{2-amino-4-chloro-7-[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]-7H-pyrrolo[2,3-d]pyrimidin-5-yl}-2-methylpent-4-yn-2 -ol
C21 H24 Cl N5 O2
Binding Affinity Annotations 
IDSourceBinding Affinity
7PP PDBBind:  3NMQ Ki: 0.2 (nM) from 1 assay(s)
BindingDB:  3NMQ Ki: 0.2 (nM) from 1 assay(s)
IC50: 1.1 (nM) from 1 assay(s)
EC50: 14 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.202 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.515α = 90
b = 90.048β = 90
c = 95.182γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
HKL-2000data reduction
HKL-2000data 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: 2010-12-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description, Structure summary