Crystal structure of a recombinant glutathione transferase, created by replacing the last seven residues of each subunit of the human class pi isoenzyme with the additional C-terminal helix of human class alpha isoenzyme

Experimental Data Snapshot

  • Resolution: 1.86 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

Starting Model: experimental
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Engineering a new C-terminal tail in the H-site of human glutathione transferase P1-1: structural and functional consequences.

Micaloni, C.Kong, G.K.W.Mazzetti, A.P.Nuccetelli, M.Antonini, G.Stella, L.McKinstry, W.J.Polekhina, G.Rossjohn, J.Federici, G.Ricci, G.Parker, M.W.Lo Bello, M.

(2003) J Mol Biol 325: 111-122

  • DOI: https://doi.org/10.1016/s0022-2836(02)01178-6
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We have sought the structural basis for the differing substrate specificities of human glutathione transferase P1-1 (class Pi) and human glutathione transferase A1-1 (class Alpha) by adding an extra helix (helix 9), found in the electrophilic substrate-binding site (H-site) of the human class Alpha enzyme, at the C terminus of the human class Pi enzyme. This class Pi-chimera (CODA) was expressed in Escherichia coli, purified and characterized by kinetic and crystallographic approaches. The presence of the newly engineered tail in the H-site of the human Pi enzyme alters its catalytic properties towards those exhibited by the human Alpha enzyme, as assessed using cumene hydroperoxide (diagnostic for class Alpha enzymes) and ethacrynic acid (diagnostic for class Pi) as co-substrates. There is a change of substrate selectivity in the latter case, as the k(cat)/K(m)(EA) value decreases about 70-fold, compared to that of class Pi. With 1-chloro-2,4-dinitrobenzene as co-substrate there is a loss of catalytic activity to about 2% with respect to that of the Pi enzyme. Crystallographic and kinetic studies of the class Pi-chimera provide important clues to explain these altered catalytic properties. The new helix forms many complimentary interactions with the rest of the protein and re-models the original electrophilic substrate-binding site towards one that is more enclosed, albeit flexible. Of particular note are the interactions between Glu205 of the new tail and the catalytic residues, Tyr7 and Tyr108, and the thiol moiety of glutathione (GSH). These interactions may provide an explanation of the more than one unit increase in the pK(a) value of the GSH thiolate and affect both the turnover number and GSH binding, using 1-chloro-2,4-dinitrobenzene as co-substrate. The data presented are consistent with the engineered tail adopting a highly mobile or disordered state in the apo form of the enzyme.

  • Organizational Affiliation

    Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica snc, 00133 Rome, Italy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Glutathione S-transferase class pi chimaera (CODA)
A, B
208Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P09211 (Homo sapiens)
Explore P09211 
Go to UniProtKB:  P09211
GTEx:  ENSG00000084207 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP09211
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.86 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.3α = 90
b = 79.3β = 90
c = 89.9γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2002-04-17
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-08-23
    Changes: Refinement description, Source and taxonomy
  • Version 1.4: 2023-08-16
    Changes: Data collection, Database references, Derived calculations, Refinement description