1GUM

HUMAN GLUTATHIONE TRANSFERASE A4-4 WITHOUT LIGANDS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.253 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Human glutathione transferase A4-4 crystal structures and mutagenesis reveal the basis of high catalytic efficiency with toxic lipid peroxidation products

Bruns, C.M.Hubatsch, I.Ridderstrom, M.Mannervik, B.Tainer, J.A.

(1999) J.Mol.Biol. 288: 427-439

  • DOI: 10.1006/jmbi.1999.2697
  • Primary Citation of Related Structures:  1GUL

  • PubMed Abstract: 
  • The oxidation of lipids and cell membranes generates cytotoxic compounds implicated in the etiology of aging, cancer, atherosclerosis, neurodegenerative diseases, and other illnesses. Glutathione transferase (GST) A4-4 is a key component in the defen ...

    The oxidation of lipids and cell membranes generates cytotoxic compounds implicated in the etiology of aging, cancer, atherosclerosis, neurodegenerative diseases, and other illnesses. Glutathione transferase (GST) A4-4 is a key component in the defense against the products of this oxidative stress because, unlike other Alpha class GSTs, GST A4-4 shows high catalytic activity with lipid peroxidation products such as 4-hydroxynon-2-enal (HNE). The crystal structure of human apo GST A4-4 unexpectedly possesses an ordered C-terminal alpha-helix, despite the absence of any ligand. The structure of human GST A4-4 in complex with the inhibitor S-(2-iodobenzyl) glutathione reveals key features of the electrophilic substrate-binding pocket which confer specificity toward HNE. Three structural modules form the binding site for electrophilic substrates and thereby govern substrate selectivity: the beta1-alpha1 loop, the end of the alpha4 helix, and the C-terminal alpha9 helix. A few residue changes in GST A4-4 result in alpha9 taking over a predominant role in ligand specificity from the N-terminal loop region important for GST A1-1. Thus, the C-terminal helix alpha9 in GST A4-4 provides pre-existing ligand complementarity rather than acting as a flexible cap as observed in other GST structures. Hydrophobic residues in the alpha9 helix, differing from those in the closely related GST A1-1, delineate a hydrophobic specificity canyon for the binding of lipid peroxidation products. The role of residue Tyr212 as a key catalytic residue, suggested by the crystal structure of the inhibitor complex, is confirmed by mutagenesis results. Tyr212 is positioned to interact with the aldehyde group of the substrate and polarize it for reaction. Tyr212 also coopts part of the binding cleft ordinarily formed by the N-terminal substrate recognition region in the homologous enzyme GST A1-1 to reveal an evolutionary swapping of function between different recognition elements. A structural model of catalysis is presented based on these results.


    Related Citations: 
    • Human Glutathione Transferase A4-4: An Alpha Class Enzyme with High Catalytic Efficiency in the Conjugation of 4-Hydroxynonenal and Other Genotoxic Products of Lipid Peroxidation
      Hubatsch, I.,Ridderstrom, M.,Mannervik, B.
      (1998) Biochem.J. 330: 175


    Organizational Affiliation

    Department of Molecular Biology MB4, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (GLUTATHIONE TRANSFERASE A4-4)
A, B, C, D, E, F, G, H
222Homo sapiensGene Names: GSTA4
EC: 2.5.1.18
Find proteins for O15217 (Homo sapiens)
Go to Gene View: GSTA4
Go to UniProtKB:  O15217
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.253 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 155.300α = 90.00
b = 156.100β = 90.00
c = 101.300γ = 90.00
Software Package:
Software NamePurpose
TNTrefinement
SCALEPACKdata scaling
AMoREphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-01-27
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance