Human carbonic anhydrase II in complex with pioglitazone

Experimental Data Snapshot

  • Resolution: 1.30 Å
  • R-Value Free: 0.145 
  • R-Value Work: 0.119 

Starting Model: experimental
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The Glitazone Class of Drugs as Carbonic Anhydrase Inhibitors-A Spin-Off Discovery from Fragment Screening.

Mueller, S.L.Chrysanthopoulos, P.K.Halili, M.A.Hepburn, C.Nebl, T.Supuran, C.T.Nocentini, A.Peat, T.S.Poulsen, S.A.

(2021) Molecules 26

  • DOI: https://doi.org/10.3390/molecules26103010
  • Primary Citation of Related Structures:  
    7M23, 7M24, 7M26

  • PubMed Abstract: 

    The approved drugs that target carbonic anhydrases (CA, EC, a family of zinc metalloenzymes, comprise almost exclusively of primary sulfonamides (R-SO 2 NH 2 ) as the zinc binding chemotype. New clinical applications for CA inhibitors, particularly for hard-to-treat cancers, has driven a growing interest in the development of novel CA inhibitors. We recently discovered that the thiazolidinedione heterocycle, where the ring nitrogen carries no substituent, is a new zinc binding group and an alternate CA inhibitor chemotype. This heterocycle is curiously also a substructure of the glitazone class of drugs used in the treatment options for type 2 diabetes. Herein, we investigate and characterise three glitazone drugs (troglitazone 11 , rosiglitazone 12 and pioglitazone 13 ) for binding to CA using native mass spectrometry, protein X-ray crystallography and hydrogen-deuterium exchange (HDX) mass spectrometry, followed by CA enzyme inhibition studies. The glitazone drugs all displayed appreciable binding to and inhibition of CA isozymes. Given that thiazolidinediones are not credited as a zinc binding group nor known as CA inhibitors, our findings indicate that CA may be an off-target of these compounds when used clinically. Furthermore, thiazolidinediones may represent a new opportunity for the development of novel CA inhibitors as future drugs.

  • Organizational Affiliation

    Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, QLD 4111, Australia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbonic anhydrase 2258Homo sapiensMutation(s): 0 
Gene Names: CA2
UniProt & NIH Common Fund Data Resources
Find proteins for P00918 (Homo sapiens)
Explore P00918 
Go to UniProtKB:  P00918
GTEx:  ENSG00000104267 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00918
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
P1B (Subject of Investigation/LOI)
Query on P1B

Download Ideal Coordinates CCD File 
C [auth A](5R)-5-{4-[2-(5-ethylpyridin-2-yl)ethoxy]benzyl}-1,3-thiazolidine-2,4-dione
C19 H20 N2 O3 S
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Experimental Data & Validation

Experimental Data

  • Resolution: 1.30 Å
  • R-Value Free: 0.145 
  • R-Value Work: 0.119 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.379α = 90
b = 41.437β = 104.38
c = 72.069γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata 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: 2022-02-02
    Type: Initial release
  • Version 1.1: 2023-10-18
    Changes: Data collection, Refinement description