Crystal Structure Analysis of W21A mutant of human GSTA1-1 in complex with S-hexylglutathione

Experimental Data Snapshot

  • Resolution: 2.13 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.174 

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Stability of the domain interface contributes towards the catalytic function at the H-site of class alpha glutathione transferase A1-1.

Balchin, D.Fanucchi, S.Achilonu, I.Adamson, R.J.Burke, J.Fernandes, M.Gildenhuys, S.Dirr, H.W.

(2010) Biochim Biophys Acta 1804: 2228-2233

  • DOI: https://doi.org/10.1016/j.bbapap.2010.09.003
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Cytosolic glutathione transferases (GSTs) are major detoxification enzymes in aerobes. Each subunit has two distinct domains and an active site consisting of a G-site for binding GSH and an H-site for an electrophilic substrate. While the active site is located at the domain interface, the role of the stability of this interface in the catalytic function of GSTs is poorly understood. Domain 1 of class alpha GSTs has a conserved tryptophan (Trp21) in helix 1 that forms a major interdomain contact with helices 6 and 8 in domain 2. Replacing Trp21 with an alanine is structurally non-disruptive but creates a cavity between helices 1, 6 and 8 thus reducing the packing density and van der Waals contacts at the domain interface. This results in destabilization of the protein and a marked reduction in catalytic activity. While functionality at the G-site is not adversely affected by the W21A mutation, the H-site becomes more accessible to solvent and less favorable for the electrophilic substrate 1-chloro-2,4-dinitrobenzene (CDNB). Not only does the mutation result in a reduction in the energy for stabilizing the transition state formed in the S(N)Ar reaction between the substrates GSH and CDNB, it also compromises the ability of the enzyme to form and stabilize a transition state analogue (Meisenheimer complex) formed between GSH and 1,3,5-trinitrobenzene (TNB). The study demonstrates that the stability of the domain-domain interface plays a role in mediating the catalytic functionality of the active site, particularly the H-site, of class alpha GSTs.

  • Organizational Affiliation

    Protein Structure-Function Research Unit, School of Molecular and Cell Biology and the School Chemistry, University of the Witwatersrand, Johannesburg, South Africa.

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Glutathione S-transferase A1
A, B
222Homo sapiensMutation(s): 1 
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
Experimental Data & Validation

Experimental Data

  • Resolution: 2.13 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.174 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 100.229α = 90
b = 94.98β = 92.63
c = 51.987γ = 90
Software Package:
Software NamePurpose
SAINTdata scaling
PDB_EXTRACTdata extraction
SAINTdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-01-12
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-13
    Changes: Database references, Derived calculations
  • Version 1.3: 2024-02-21
    Changes: Data collection