1GTU

LIGAND-FREE HUMAN GLUTATHIONE S-TRANSFERASE M1A-1A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.68 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.211 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Functions of His107 in the catalytic mechanism of human glutathione S-transferase hGSTM1a-1a.

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

(1999) Biochemistry 38: 1193-1202

  • DOI: 10.1021/bi982164m

  • PubMed Abstract: 
  • Domain interchange analyses and site-directed mutagenesis indicate that the His107 residue of the human subunit hGSTM1 has a pronounced influence on catalysis of nucleophilic aromatic substitution reactions, and a H107S substitution accounts for the ...

    Domain interchange analyses and site-directed mutagenesis indicate that the His107 residue of the human subunit hGSTM1 has a pronounced influence on catalysis of nucleophilic aromatic substitution reactions, and a H107S substitution accounts for the marked differences in the properties of the homologous hGSTM1-1 (His107) and hGSTM4-4 (Ser107) glutathione S-transferases. Reciprocal replacement of His107 and Ser107 in chimeric enzymes results in reciprocal conversion of catalytic properties. With 1-chloro-2, 4-dinitrobenzene as a substrate, the His107 residue primarily influences the pH dependence of catalysis by lowering the apparent pKa of kcat/Km from 7.8 for the Ser107-containing enzymes to 6.3 for the His107-containing enzymes. There is a parallel shift in the pKa for thiolate anion formation of enzyme-bound GSH. Y6F mutations have no effect on the pKa for these enzymes. Crystal structures of hGSTM1a-1a indicate that the imidazole ring of His107 is oriented toward the substrate binding cleft approximately 6 A from the GSH thiol group. Thus, His107 has the potential to act as a general base in proton transfer mediated through an active site water molecule or directly following a modest conformational change, to promote thiolate anion formation. All wild-type enzymes and H107S chimera have nearly identical equilibrium constants for formation of enzyme-GSH complexes (Kd values of 1-2 x 10(-)6 M); however, KmGSH and Ki values for S-methylglutathione inhibition determined by steady-state kinetics are nearly 100-fold higher. The functions of His107 of hGSTM1a-1a are unexpected in view of a substantial body of previous evidence that excluded participation of histidine residues in the catalytic mechanisms of other glutathione S-transferases. Consequences of His107 involvement in catalysis are also substrate-dependent; in contrast to 1-chloro-2,4-dinitrobenzene, for the nucleophilic addition reaction of GSH to ethacrynic acid, the H107S substitution has no effect on catalysis presumably because product release is rate-limiting.


    Related Citations: 
    • Deduced Amino Acid Sequence, Gene Structure and Chromosomal Location of a Novel Human Class Mu Glutathione S-Transferase, Gstm4
      Zhong, S.,Spurr, N.K.,Hayes, J.D.,Wolf, C.R.
      (1993) Biochem.J. 291: 41
    • Hereditary Differences in the Expression of the Human Glutathione Transferase Active on Trans-Stilbene Oxide are due to a Gene Deletion
      Seidegard, J.,Vorachek, W.R.,Pero, R.W.,Pearson, W.R.
      (1988) Proc.Natl.Acad.Sci.USA 85: 7293
    • The Human Liver Glutathione S-Transferase Gene Superfamily: Expression and Chromosome Mapping of an Hb Subunit Cdna
      Dejong, J.L.,Chang, C.M.,Whang-Peng, J.,Knutsen, T.,TU, C.P.
      (1988) Nucleic Acids Res. 16: 8541


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GLUTATHIONE S-TRANSFERASE
A, B, C, D
217Homo sapiensMutation(s): 0 
Gene Names: GSTM1 (GST1)
EC: 2.5.1.18
Find proteins for P09488 (Homo sapiens)
Go to Gene View: GSTM1
Go to UniProtKB:  P09488
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.68 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.211 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 56.957α = 90.00
b = 84.987β = 90.00
c = 215.382γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
XSCALEdata scaling
XDSdata reduction
X-PLORphasing
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-02-02
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance