Glutathione transferase A2-2 in complex with delta-4-andostrene-3-17- dione

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.221 

Starting Model: experimental
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Structural Basis for Featuring of Steroid Isomerase Activity in Alpha Class Glutathione Transferases.

Tars, K.Olin, B.Mannervik, B.

(2010) J Mol Biol 397: 332

  • DOI: https://doi.org/10.1016/j.jmb.2010.01.023
  • Primary Citation of Related Structures:  
    2VCT, 2VCV, 2WJU

  • PubMed Abstract: 

    Glutathione transferases (GSTs) are abundant enzymes catalyzing the conjugation of hydrophobic toxic substrates with glutathione. In addition to detoxication, human GST A3-3 displays prominent steroid double-bond isomerase activity; e.g. transforming Delta(5)-androstene-3-17-dione into Delta(4)-androstene-3-17-dione (AD). This chemical transformation is a crucial step in the biosynthesis of steroids, such as testosterone and progesterone. In contrast to GST A3-3, the homologous GST A2-2 does not show significant steroid isomerase activity. We have solved the 3D structures of human GSTs A2-2 and A3-3 in complex with AD. In the GST A3-3 crystal structure, AD was bound in an orientation suitable for the glutathione (GSH)-mediated catalysis to occur. In GST A2-2, however, AD was bound in a completely different orientation with its reactive double bond distant from the GSH-binding site. The structures illustrate how a few amino acid substitutions in the active site spectacularly alter the binding mode of the steroid substrate in relation to the conserved catalytic groups and an essentially fixed polypeptide chain conformation. Furthermore, AD did not bind to the GST A2-2-GSH complex. Altogether, these results provide a first-time structural insight into the steroid isomerase activity of any GST and explain the 5000-fold difference in catalytic efficiency between GSTs A2-2 and A3-3. More generally, the structures illustrate how dramatic diversification of functional properties can arise via minimal structural alterations. We suggest a novel structure-based mechanism of the steroid isomerization reaction.

  • Organizational Affiliation

    Latvian Biomedical Research and Study Centre, Ratsupites 1, Riga, Latvia, Sweden. kaspars@biomed.lu.lv

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F, G, H
222Homo sapiensMutation(s): 1 
UniProt & NIH Common Fund Data Resources
Find proteins for P09210 (Homo sapiens)
Explore P09210 
Go to UniProtKB:  P09210
GTEx:  ENSG00000244067 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP09210
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.221 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 105.546α = 90
b = 97.343β = 115
c = 110.302γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-10-28
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-05-08
    Changes: Data collection, Experimental preparation, Other
  • Version 1.4: 2019-10-23
    Changes: Data collection, Database references, Other
  • Version 1.5: 2023-12-13
    Changes: Data collection, Database references, Derived calculations, Refinement description