1XQ0

Structure of human carbonic anhydrase II with 4-[(3-bromo-4-O-sulfamoylbenzyl)(4-cyanophenyl)amino]-4H-[1,2,4]-triazole


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

First Crystal Structures of Human Carbonic Anhydrase II in Complex with Dual Aromatase-Steroid Sulfatase Inhibitors(,)

Lloyd, M.D.Thiyagarajan, N.Ho, Y.T.Woo, L.W.L.Sutcliffe, O.B.Purohit, A.Reed, M.J.Acharya, K.R.Potter, B.V.L.

(2005) Biochemistry 44: 6858-6866

  • DOI: https://doi.org/10.1021/bi047692e
  • Primary Citation of Related Structures:  
    1XPZ, 1XQ0

  • PubMed Abstract: 

    Carbonic anhydrase (CA) catalyzes the reversible hydration of carbon dioxide to hydrogen carbonate. The role of CA in maintaining pH balance has made it an attractive drug target for the treatment of cancer, and it has recently been implicated in the delivery of sulfamate-containing drugs. With the acceptance of steroid sulfatase as a target for hormone-dependent cancer, novel dual aromatase-steroid sulfatase inhibitors (DASIs) containing a sulfamate group are now being developed. In this study, we show that CA II is potently inhibited by several members of this class of inhibitor. The structures of CA II complexed with 4-[(4-O-sulfamoylbenzyl)(4-cyanophenyl)amino]-4H-[1,2,4]triazole (K(D) = 84 +/- 5 nM) and 4-[(3-bromo-4-O-sulfamoylbenzyl)(4-cyanophenyl)amino]-4H-[1,2,4]triazole (K(D) = 454 +/- 29 nM) are reported to 2.02 and 1.76 A, respectively. Both inhibitors ligate to the active site zinc(II) atom via their sulfamate nitrogen, while the rest of the molecule is contained within the hydrophobic binding pocket. Key protein residues include Val-121, Phe-131, Val-135, Val-143, Leu-141, Leu-198, Pro-202, and Leu-204. Despite being structurally similar, the two ligands experience different types of binding particularly in the sulfamate-containing aromatic ring and the opposite geometric arrangement of the triazole and cyanophenyl groups around the configurationally invertible central nitrogen atom. Small changes in inhibitor structure can cause large changes in binding to CA II, and this underlines the importance of structure-based drug design with this enzyme and other isoforms relevant to potential anticancer therapy. Moreover, these results underpin the idea that binding to erythrocyte CA II may be a general method of stabilizing and delivering sulfamate-based drugs in vivo.


  • Organizational Affiliation

    Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom. M.D.Lloyd@bath.ac.uk


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbonic anhydrase II259Homo sapiensMutation(s): 0 
Gene Names: CA2
EC: 4.2.1.1
UniProt & NIH Common Fund Data Resources
Find proteins for P00918 (Homo sapiens)
Explore P00918 
Go to UniProtKB:  P00918
PHAROS:  P00918
GTEx:  ENSG00000104267 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00918
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
4TR
Query on 4TR

Download Ideal Coordinates CCD File 
D [auth A]2-BROMO-4-{[(4-CYANOPHENYL)(4H-1,2,4-TRIAZOL-4-YL)AMINO]METHYL}PHENYL SULFAMATE
C16 H13 Br N6 O3 S
GHDKYBCUDPSXGJ-UHFFFAOYSA-N
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A],
C [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
Binding Affinity Annotations 
IDSourceBinding Affinity
4TR Binding MOAD:  1XQ0 Kd: 454 (nM) from 1 assay(s)
PDBBind:  1XQ0 Kd: 454 (nM) from 1 assay(s)
BindingDB:  1XQ0 IC50: 137 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.76 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.551α = 90
b = 72.656β = 90
c = 75.103γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-05-17
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-10-25
    Changes: Data collection, Database references, Derived calculations, Refinement description