8VV1 | pdb_00008vv1

Estrogen receptor alpha ligand binding domain in complex with palazestrant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 
    0.231 (Depositor), 0.234 (DCC) 
  • R-Value Work: 
    0.199 (Depositor), 0.204 (DCC) 
  • R-Value Observed: 
    0.201 (Depositor) 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

Discovery of Palazestrant (OP-1250), a Potent and Orally Bioavailable Complete Estrogen Receptor Antagonist (CERAN) and Selective Estrogen Receptor Degrader (SERD).

Ng, R.A.Barratt, S.Parisian, A.Palanisamy, G.S.Phukan, S.Sun, R.Robello, B.Pena, G.Sapugay, J.Yeghikyan, D.Wang, C.Satish Kher, S.Thangathirupathy, S.Millikin, R.Yu, G.Watanabe, T.Zhou, F.Rich, B.Duncan, A.Andersen, S.E.Chawla, R.Zak, D.R.Heerding, D.A.Hearn, B.R.Greene, G.Harmon, C.L.Hodges-Gallagher, L.Kushner, P.J.Fanning, S.W.Myles, D.C.

(2025) ACS Omega 10: 22685-22700

  • DOI: https://doi.org/10.1021/acsomega.4c11023
  • Primary Citation Related Structures: 
    8VV1

  • PubMed Abstract: 

    Metastatic breast cancer (mBC) is a leading cause of cancer death in women. Most breast cancer patients are administered estrogen-receptor-targeted endocrine therapies to treat or prevent progressive metastatic disease. Development of endocrine resistance through acquisition of mutations in the estrogen receptor gene, ESR1 , that constitutively activate the estrogen receptor leads to relapse. Complete antagonism of both WT and mutant ESR1 ( mutESR1 ) with an oral therapeutic that persistently antagonizes ER-driven oncogenic transcriptional activities is a requirement for efficacy. Here, we describe our discovery of the investigational drug OP-1250 (palazestrant). OP-1250 is a potent complete estrogen receptor antagonist (CERAN) and selective estrogen receptor degrader (SERD) that is active in both WT and mutESR1 breast cancer tumors. OP-1250's effective induction of tumor regression either as a single agent or in combination with a CDK4/6 inhibitor has led to the rapid advancement of this compound into a Phase 3 clinical trial (OPERA-01).


  • Organizational Affiliation
    • Olema Oncology, 780 Brannan Street, San Francisco 94107, California, United States.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Estrogen receptor
A, B
249Homo sapiensMutation(s): 3 
Gene Names: ESR1ESRNR3A1
UniProt & NIH Common Fund Data Resources
Find proteins for P03372 (Homo sapiens)
Explore P03372 
Go to UniProtKB:  P03372
PHAROS:  P03372
GTEx:  ENSG00000091831 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP03372
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free:  0.231 (Depositor), 0.234 (DCC) 
  • R-Value Work:  0.199 (Depositor), 0.204 (DCC) 
  • R-Value Observed: 0.201 (Depositor) 
Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 102.126α = 90
b = 57.268β = 103.01
c = 87.147γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2025-03-19
    Type: Initial release
  • Version 1.1: 2026-04-01
    Changes: Database references