3VLN

Human Glutathione Transferase O1-1 C32S Mutant in Complex with Ascorbic Acid


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.182 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Structural insights into the dehydroascorbate reductase activity of human omega-class glutathione transferases.

Zhou, H.Brock, J.Liu, D.Board, P.G.Oakley, A.J.

(2012) J Mol Biol 420: 190-203

  • DOI: 10.1016/j.jmb.2012.04.014
  • Primary Citation of Related Structures:  
    3Q18, 3Q19, 3QAG, 3VLN

  • PubMed Abstract: 
  • The reduction of dehydroascorbate (DHA) to ascorbic acid (AA) is a vital cellular function. The omega-class glutathione transferases (GSTs) catalyze several reductive reactions in cellular biochemistry, including DHA reduction. In humans, two isozymes (GSTO1-1 and GSTO2-2) with significant DHA reductase (DHAR) activity are found, sharing 64% sequence identity ...

    The reduction of dehydroascorbate (DHA) to ascorbic acid (AA) is a vital cellular function. The omega-class glutathione transferases (GSTs) catalyze several reductive reactions in cellular biochemistry, including DHA reduction. In humans, two isozymes (GSTO1-1 and GSTO2-2) with significant DHA reductase (DHAR) activity are found, sharing 64% sequence identity. While the activity of GSTO2-2 is higher, it is significantly more unstable in vitro. We report the first crystal structures of human GSTO2-2, stabilized through site-directed mutagenesis and determined at 1.9 Å resolution in the presence and absence of glutathione (GSH). The structure of a human GSTO1-1 has been determined at 1.7 Å resolution in complex with the reaction product AA, which unexpectedly binds in the G-site, where the glutamyl moiety of GSH binds. The structure suggests a similar mode of ascorbate binding in GSTO2-2. This is the first time that a non-GSH-based reaction product has been observed in the G-site of any GST. AA stacks against a conserved aromatic residue, F34 (equivalent to Y34 in GSTO2-2). Mutation of Y34 to alanine in GSTO2-2 eliminates DHAR activity. From these structures and other biochemical data, we propose a mechanism of substrate binding and catalysis of DHAR activity.


    Organizational Affiliation

    John Curtin School of Medical Research, Australian National University, Canberra, ACT 0200, Australia.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Glutathione S-transferase omega-1A241Homo sapiensMutation(s): 1 
Gene Names: GSTO1GSTTLP28
EC: 2.5.1.18 (PDB Primary Data), 1.8.5.1 (UniProt), 1.20.4.2 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P78417 (Homo sapiens)
Explore P78417 
Go to UniProtKB:  P78417
PHAROS:  P78417
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP78417
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.182 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.918α = 90
b = 56.918β = 90
c = 140.511γ = 120
Software Package:
Software NamePurpose
Blu-Icedata collection
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-05-16
    Type: Initial release
  • Version 1.1: 2013-06-26
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Advisory, Refinement description
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Database references, Derived calculations