Experimental Data Snapshot

  • Resolution: 2.55 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.203 

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The enhanced affinity for thiolate anion and activation of enzyme-bound glutathione is governed by an arginine residue of human Mu class glutathione S-transferases.

Patskovsky, Y.V.Patskovska, L.N.Listowsky, I.

(2000) J Biol Chem 275: 3296-3304

  • DOI: https://doi.org/10.1074/jbc.275.5.3296
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A series of chimeric human Mu class glutathione S-transferases were designed to determine mechanisms by which they activate enzyme-bound glutathione (GSH) for reaction with electrophilic substrates. In view of evidence that the His(107) residue of hGSTM1a-1a is important for catalysis (Patskovsky, Y. V., Patskovska, L. N., and Listowsky, I. (1999) Biochemistry 38, 1193-1202), the cognate Arg(107) residue of the hGSTM2 subunit was replaced (R107N or R107H) and arginine residues were also incorporated into position 107 of hGSTM1 (H107R) and hGSTM4 (S107R) subunits. The major distinguishing kinetic properties invariably associated with enzymes containing an Arg(107) residue include an inverse dependence of k(cat) on viscosity and lower K(m(GSH values relative to enzymes with other residues at that position. Moreover, affinities for GSH thiolate anion binding are greater for enzymes containing Arg(107))), with K(d) values of 20-50 microM that are consistent with the K(m(GSH values (10-25 microM) obtained by steady-state kinetic analyses. Both thermodynamic and kinetic and data indicate that the Arg(107))) residue is specifically involved in enhancing the binding affinity of GSH thiolate anion relative to that of the protonated form. These enzymes therefore, can be more effective at lower GSH concentrations. Combined mutations indicate that both Arg(107) and Tyr(6) residues are required for thiolate anion formation and stabilization. The three-dimensional structure of ligand-free hGSTM2-2 determined by x-ray crystallography suggests that Arg(107) maintains an electrostatic interaction with the Asp(161) side chain (3 A apart), but is distant from the GSH-binding site. However, an alternative energetically favorable model places the guanidino group 4 A from the sulfur atom of bound GSH. It is suggested therefore, that in solution, motion of the positively charged arginine into the catalytic pocket could provide a counter ion to promote ionization of the sulfhydryl group of GSH, thereby accounting for the observed greater affinity of enzymes containing Arg(107) for binding of thiolate anion.

  • Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
217Homo sapiensMutation(s): 0 
Gene Names: GSTM2
UniProt & NIH Common Fund Data Resources
Find proteins for P28161 (Homo sapiens)
Explore P28161 
Go to UniProtKB:  P28161
PHAROS:  P28161
GTEx:  ENSG00000213366 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP28161
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.55 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.203 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.909α = 90
b = 81.479β = 109.26
c = 55.621γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-03-02
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-09
    Changes: Database references, Other, Refinement description
  • Version 1.4: 2024-05-29
    Changes: Data collection