Helix-stabilized cyclic peptides as selective inhibitors of steroid receptor-coactivator interactions

Experimental Data Snapshot

  • Resolution: 2.70 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.219 

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Helix-stabilized cyclic peptides as selective inhibitors of steroid receptor-coactivator interactions

Leduc, A.M.Trent, J.O.Wittliff, J.L.Bramlett, K.S.Briggs, S.L.Chirgadze, N.Y.Wang, Y.Burris, T.P.Spatola, A.F.

(2003) Proc Natl Acad Sci U S A 100: 11273-11278

  • DOI: https://doi.org/10.1073/pnas.1934759100
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The interaction between nuclear receptors and coactivators provides an arena for testing whether protein-protein interactions may be inhibited by small molecule drug candidates. We provide evidence that a short cyclic peptide, containing a copy of the LXXLL nuclear receptor box pentapeptide, binds tightly and selectively to estrogen receptor alpha. Furthermore, as shown by x-ray analysis, the disulfide-bridged nonapeptide, nonhelical in aqueous solutions, is able to adopt a quasihelical conformer while binding to the groove created by ligand attachment to estrogen receptor alpha. An i, i+3 linked analog, H-Lys-cyclo(d-Cys-Ile-Leu-Cys)-Arg-Leu-Leu-Gln-NH2 (peptidomimetic estrogen receptor modulator 1), binds with a Ki of 25 nM, significantly better than an i, i+4 bridged cyclic amide, as predicted by molecular modeling design criteria. The induction of helical character, effective binding, and receptor selectivity exhibited by this peptide analog provide strong support for this strategy. The stabilization of minimalist surface motifs may prove useful for the control of other macromolecular assemblies, especially when an amphiphilic helix is crucial for the strong binding interaction between two proteins.

  • Organizational Affiliation

    Department of Chemistry, University of Louisville, Louisville, KY 40292, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
estrogen receptor
A, B
244Homo sapiensMutation(s): 3 
UniProt & NIH Common Fund Data Resources
Find proteins for P03372 (Homo sapiens)
Explore P03372 
Go to UniProtKB:  P03372
GTEx:  ENSG00000091831 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP03372
Sequence Annotations
  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
peptide inhibitorC [auth E],
D [auth F]
9N/AMutation(s): 0 
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
EST BindingDB:  1PCG Ki: min: 0.11, max: 100 (nM) from 13 assay(s)
Kd: min: 0.2, max: 100 (nM) from 4 assay(s)
IC50: min: 1.00e-2, max: 46 (nM) from 46 assay(s)
EC50: min: 4.00e-3, max: 10 (nM) from 52 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.70 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.219 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.809α = 90
b = 102.432β = 90
c = 195.326γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-10-28
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references, Derived calculations