4OLC

Carbamate kinase from Giardia lamblia thiocarbamoylated by disulfiram on Cys242


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.274 
  • R-Value Work: 0.206 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structural Basis for Inactivation of Giardia lamblia Carbamate Kinase by Disulfiram.

Galkin, A.Kulakova, L.Lim, K.Chen, C.Z.Zheng, W.Turko, I.V.Herzberg, O.

(2014) J Biol Chem 289: 10502-10509

  • DOI: https://doi.org/10.1074/jbc.M114.553123
  • Primary Citation of Related Structures:  
    4OLC

  • PubMed Abstract: 

    Carbamate kinase from Giardia lamblia is an essential enzyme for the survival of the organism. The enzyme catalyzes the final step in the arginine dihydrolase pathway converting ADP and carbamoyl phosphate to ATP and carbamate. We previously reported that disulfiram, a drug used to treat chronic alcoholism, inhibits G. lamblia CK and kills G. lamblia trophozoites in vitro at submicromolar IC50 values. Here, we examine the structural basis for G. lamblia CK inhibition of disulfiram and its analog, thiram, their activities against both metronidazole-susceptible and metronidazole-resistant G. lamblia isolates, and their efficacy in a mouse model of giardiasis. The crystal structure of G. lamblia CK soaked with disulfiram revealed that the compound thiocarbamoylated Cys-242, a residue located at the edge of the active site. The modified Cys-242 prevents a conformational transition of a loop adjacent to the ADP/ATP binding site, which is required for the stacking of Tyr-245 side chain against the adenine moiety, an interaction seen in the structure of G. lamblia CK in complex with AMP-PNP. Mass spectrometry coupled with trypsin digestion confirmed the selective covalent thiocarbamoylation of Cys-242 in solution. The Giardia viability studies in the metronidazole-resistant strain and the G. lamblia CK irreversible inactivation mechanism show that the thiuram compounds can circumvent the resistance mechanism that renders metronidazole ineffectiveness in drug resistance cases of giardiasis. Together, the studies suggest that G. lamblia CK is an attractive drug target for development of novel antigiardial therapies and that disulfiram, an FDA-approved drug, is a promising candidate for drug repurposing.


  • Organizational Affiliation

    Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850; Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742. Electronic address: osnat@umd.edu.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbamate kinase
A, B, C, D
317Giardia lamblia ATCC 50803Mutation(s): 0 
Gene Names: GL50803_16453
EC: 2.7.2.2
UniProt
Find proteins for A8BB85 (Giardia intestinalis (strain ATCC 50803 / WB clone C6))
Explore A8BB85 
Go to UniProtKB:  A8BB85
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA8BB85
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.274 
  • R-Value Work: 0.206 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.297α = 90
b = 98.178β = 107.57
c = 102.674γ = 90
Software Package:
Software NamePurpose
JBluIce-EPICSdata collection
PHASERphasing
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-26
    Type: Initial release
  • Version 1.1: 2014-03-26
    Changes: Database references
  • Version 1.2: 2014-04-30
    Changes: Database references
  • Version 1.3: 2017-11-22
    Changes: Refinement description
  • Version 1.4: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description