9BQB | pdb_00009bqb

Human Topoisomerase 2 Alpha ATPase domain bound to topobexin and non-hydrolyzable ATP analog AMPPNP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 
    0.176 (Depositor), 0.185 (DCC) 
  • R-Value Work: 
    0.140 (Depositor), 0.157 (DCC) 
  • R-Value Observed: 
    0.140 (Depositor) 

Starting Model: experimental
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Literature

Topobexin targets the Topoisomerase II ATPase domain for beta isoform-selective inhibition and anthracycline cardioprotection.

Kubes, J.Karabanovich, G.Cong, A.T.Q.Melnikova, I.Lencova, O.Kollarova, P.Bavlovic Piskackova, H.Kerestes, V.Applova, L.Arrouye, L.C.M.Alvey, J.R.Paluncic, J.Witter, T.L.Jirkovska, A.Kunes, J.Sterbova-Kovarikova, P.Austin, C.A.Sterba, M.Simunek, T.Roh, J.Schellenberg, M.J.

(2025) Nat Commun 16: 4928-4928

  • DOI: https://doi.org/10.1038/s41467-025-60167-9
  • Primary Citation of Related Structures:  
    9BQ6, 9BQ7, 9BQ8, 9BQ9, 9BQA, 9BQB, 9BQC, 9BQD

  • PubMed Abstract: 

    Topoisomerase II alpha and beta (TOP2A and TOP2B) isoenzymes perform essential and non-redundant cellular functions. Anthracyclines induce their potent anti-cancer effects primarily via TOP2A, but at the same time they induce a dose limiting cardiotoxicity through TOP2B. Here we describe the development of the obex class of TOP2 inhibitors that bind to a previously unidentified druggable pocket in the TOP2 ATPase domain to act as allosteric catalytic inhibitors by locking the ATPase domain conformation with the capability of isoform-selective inhibition. Through rational drug design we have developed topobexin, which interacts with residues that differ between TOP2A and TOP2B to provide inhibition that is both selective for TOP2B and superior to dexrazoxane. Topobexin is a potent protectant against chronic anthracycline cardiotoxicity in an animal model. This demonstration of TOP2 isoform-specific inhibition underscores the broader potential to improve drug specificity and minimize adverse effects in various medical treatments.


  • Organizational Affiliation

    Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University; Hradec, Králové, 500 03, Czech Republic.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA topoisomerase 2-alpha
A, B
399Homo sapiensMutation(s): 0 
Gene Names: TOP2ATOP2
EC: 5.6.2.2
UniProt & NIH Common Fund Data Resources
Find proteins for P11388 (Homo sapiens)
Explore P11388 
Go to UniProtKB:  P11388
PHAROS:  P11388
GTEx:  ENSG00000131747 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP11388
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ANP
Query on ANP

Download Ideal Coordinates CCD File 
C [auth A],
G [auth B]
PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER
C10 H17 N6 O12 P3
PVKSNHVPLWYQGJ-KQYNXXCUSA-N
A1ASC (Subject of Investigation/LOI)
Query on A1ASC

Download Ideal Coordinates CCD File 
E [auth A],
J [auth B]
8-(3,4-dihydroquinoline-1(2H)-carbonyl)-7-[2-(4-methylpiperazin-1-yl)ethoxy]-4-propyl-2H-1-benzopyran-2-one
C29 H35 N3 O4
LNTXOIHSBUUKNJ-UHFFFAOYSA-N
GOL
Query on GOL

Download Ideal Coordinates CCD File 
I [auth B]GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
CL
Query on CL

Download Ideal Coordinates CCD File 
F [auth A],
K [auth B]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
MG
Query on MG

Download Ideal Coordinates CCD File 
D [auth A],
H [auth B]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free:  0.176 (Depositor), 0.185 (DCC) 
  • R-Value Work:  0.140 (Depositor), 0.157 (DCC) 
  • R-Value Observed: 0.140 (Depositor) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 69.798α = 90
b = 92.536β = 90
c = 125.585γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
SCALEPACKdata scaling
DENZOdata reduction
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Revision History  (Full details and data files)

  • Version 1.0: 2025-06-25
    Type: Initial release