1C72

TYR115, GLN165 AND TRP209 CONTRIBUTE TO THE 1,2-EPOXY-3-(P-NITROPHENOXY)PROPANE CONJUGATING ACTIVITIES OF GLUTATHIONE S-TRANSFERASE CGSTM1-1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.190 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Tyr115, gln165 and trp209 contribute to the 1, 2-epoxy-3-(p-nitrophenoxy)propane-conjugating activity of glutathione S-transferase cGSTM1-1.

Chern, M.K.Wu, T.C.Hsieh, C.H.Chou, C.C.Liu, L.F.Kuan, I.C.Yeh, Y.H.Hsiao, C.D.Tam, M.F.

(2000) J.Mol.Biol. 300: 1257-1269

  • DOI: 10.1006/jmbi.2000.3904

  • PubMed Abstract: 
  • We investigated the epoxidase activity of a class mu glutathione S-transferase (cGSTM1-1), using 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) as substrate. Trp209 on the C-terminal tail, Arg107 on the alpha4 helix, Asp161 and Gln165 on the alpha6 helix ...

    We investigated the epoxidase activity of a class mu glutathione S-transferase (cGSTM1-1), using 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) as substrate. Trp209 on the C-terminal tail, Arg107 on the alpha4 helix, Asp161 and Gln165 on the alpha6 helix of cGSTM1-1 were selected for mutagenesis and kinetic studies. A hydrophobic side-chain at residue 209 is needed for the epoxidase activity of cGSTM1-1. Replacing Trp209 with histidine, isoleucine or proline resulted in a fivefold to 28-fold decrease in the k(cat)(app) of the enzyme, while a modest 25 % decrease in the k(cat)(app) was observed for the W209F mutant. The rGSTM1-1 enzyme has serine at the correponding position. The k(cat)(app) of the S209W mutant is 2. 5-fold higher than that of the wild-type rGSTM1-1. A charged residue is needed at position 107 of cGSTM1-1. The K(m)(app)(GSH) of the R107L mutant is 38-fold lower than that of the wild-type enzyme. On the contrary, the R107E mutant has a K(m)(app)(GSH) and a k(cat)(app) that are 11-fold and 35 % lower than those of the wild-type cGSTM1-1. The substitutions of Gln165 with Glu or Leu have minimal effect on the affinity of the mutants towards GSH or EPNP. However, a discernible reduction in k(cat)(app) was observed. Asp161 is involved in maintaining the structural integrity of the enzyme. The K(m)(app)(GSH) of the D161L mutant is 616-fold higher than that of the wild-type enzyme. In the hydrogen/deuterium exchange experiments, this mutant has the highest level of deuteration among all the proteins tested. We also elucidated the structure of cGSTM1-1 co-crystallized with the glutathionyl-conjugated 1, 2-epoxy-3-(p-nitrophenoxy)propane (EPNP) at 2.8 A resolution. The product found in the active site was 1-hydroxy-2-(S-glutathionyl)-3-(p-nitrophenoxy)propane, instead of the conventional 2-hydroxy isomer. The EPNP moiety orients towards Arg107 and Gln165 in dimer AB, and protrudes into a hydrophobic region formed by the loop connecting beta1 and alpha1 and part of the C-terminal tail in dimer CD. The phenoxyl ring forms strong ring stacking with the Trp209 side-chain in dimer CD. We hypothesize that these two conformations represent the EPNP moiety close to the initial and final stages of the reaction mechanism, respectively.


    Related Citations: 
    • The Three-Dimensional Structure of an Avian Class-Mu Glutathione S-Transferase, cGSTM1-1 at 1.94A Resolution
      Sun, Y.J.,Kuan, I.C.,Tam, M.F.,Hsiao, C.D.
      (1998) J.Mol.Biol. 278: 239


    Organizational Affiliation

    Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, 11529, ROC.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (GLUTATHIONE S-TRANSFERASE)
A, B, C, D
219Gallus gallusGene Names: GSTM2
EC: 2.5.1.18
Find proteins for P20136 (Gallus gallus)
Go to Gene View: GSTM2
Go to UniProtKB:  P20136
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EPY
Query on EPY

Download SDF File 
Download CCD File 
A, B, C, D
1-HYDROXY-2-S-GLUTATHIONYL-3-PARA-NITROPHENOXY-PROPANE
C19 H26 N4 O10 S
YWXHXYSGHBAIBL-KKUMJFAQSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.190 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 125.600α = 90.00
b = 136.650β = 90.00
c = 125.740γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
SCALEPACKdata scaling
X-PLORrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-08-30
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance