Crystal Structure Analysis of GSTA1-1 in complex with chlorambucil

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.215 

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The interaction of the chemotherapeutic drug chlorambucil with human glutathione transferase A1-1: kinetic and structural analysis.

Karpusas, M.Axarli, I.Chiniadis, L.Papakyriakou, A.Bethanis, K.Scopelitou, K.Clonis, Y.D.Labrou, N.E.

(2013) PLoS One 8: e56337-e56337

  • DOI: https://doi.org/10.1371/journal.pone.0056337
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Glutathione transferases (GSTs) are enzymes that contribute to cellular detoxification by catalysing the nucleophilic attack of glutathione (GSH) on the electrophilic centre of a number of xenobiotic compounds, including several chemotherapeutic drugs. In the present work we investigated the interaction of the chemotherapeutic drug chlorambucil (CBL) with human GSTA1-1 (hGSTA1-1) using kinetic analysis, protein crystallography and molecular dynamics. In the presence of GSH, CBL behaves as an efficient substrate for hGSTA1-1. The rate-limiting step of the catalytic reaction between CBL and GSH is viscosity-dependent and kinetic data suggest that product release is rate-limiting. The crystal structure of the hGSTA1-1/CBL-GSH complex was solved at 2.1 Å resolution by molecular replacement. CBL is bound at the H-site attached to the thiol group of GSH, is partially ordered and exposed to the solvent, making specific interactions with the enzyme. Molecular dynamics simulations based on the crystal structure indicated high mobility of the CBL moiety and stabilization of the C-terminal helix due to the presence of the adduct. In the absence of GSH, CBL is shown to be an alkylating irreversible inhibitor for hGSTA1-1. Inactivation of the enzyme by CBL followed a biphasic pseudo-first-order saturation kinetics with approximately 1 mol of CBL per mol of dimeric enzyme being incorporated. Structural analysis suggested that the modifying residue is Cys112 which is located at the entrance of the H-site. The results are indicative of a structural communication between the subunits on the basis of mutually exclusive modification of Cys112, indicating that the two enzyme active sites are presumably coordinated.

  • Organizational Affiliation

    Physics Laboratory, Department of Science, Agricultural University of Athens, Athens, Greece.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Glutathione S-transferase A1
A, B
217Homo sapiensMutation(s): 0 
Gene Names: GSTA1
UniProt & NIH Common Fund Data Resources
Find proteins for P08263 (Homo sapiens)
Explore P08263 
Go to UniProtKB:  P08263
GTEx:  ENSG00000243955 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08263
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on LZ6

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C24 H35 Cl N4 O8 S
Binding Affinity Annotations 
IDSourceBinding Affinity
LZ6 PDBBind:  4HJ2 Kd: 2.95e+6 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.215 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 99α = 90
b = 93.53β = 93.91
c = 51.18γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-27
    Type: Initial release
  • Version 1.1: 2024-02-28
    Changes: Data collection, Database references, Derived calculations