1YDK

Crystal structure of the I219A mutant of human glutathione transferase A1-1 with S-hexylglutathione


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.203 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Tertiary Interactions Stabilise the C-terminal Region of Human Glutathione Transferase A1-1: a Crystallographic and Calorimetric Study.

Kuhnert, D.C.Sayed, Y.Mosebi, S.Sayed, M.Sewell, T.Dirr, H.W.

(2005) J.Mol.Biol. 349: 825-838

  • DOI: 10.1016/j.jmb.2005.04.025

  • PubMed Abstract: 
  • The C-terminal region in class Alpha glutathione transferase A1-1 (GSTA1-1), which forms an amphipathic alpha-helix (helix 9), is known to contribute to the catalytic and non-substrate ligand-binding functions of the enzyme. The region in the apo pro ...

    The C-terminal region in class Alpha glutathione transferase A1-1 (GSTA1-1), which forms an amphipathic alpha-helix (helix 9), is known to contribute to the catalytic and non-substrate ligand-binding functions of the enzyme. The region in the apo protein is proposed to be disordered which, upon ligand binding at the active-site, becomes structured and localised. Because Ile219 plays a pivotal role in the stability and localisation of the region, the role of tertiary interactions mediated by Ile219 in determining the conformation and dynamics of the C-terminal region were studied. Ligand-binding microcalorimetric and X-ray structural data were obtained to characterise ligand binding at the active-site and the associated localisation of the C-terminal region. In the crystal structure of the I219A hGSTA1-1.S-hexylglutathione complex, the C-terminal region of one chain is mobile and not observed (unresolved electron density), whereas the corresponding region of the other chain is localised and structured as a result of crystal packing interactions. In solution, the mutant C-terminal region of both chains in the complex is mobile and delocalised resulting in a hydrated, less hydrophobic active-site and a reduction in the affinity of the protein for S-hexylglutathione. Complete dehydration of the active-site, important for maintaining the highly reactive thiolate form of glutathione, requires the binding of ligands and the subsequent localisation of the C-terminal region. Thermodynamic data demonstrate that the mobile C-terminal region in apo hGSTA1-1 is structured and does not undergo ligand-induced folding. Its close proximity to the surface of the wild-type protein is indicated by the concurrence between the observed heat capacity change of complex formation and the type and amount of surface area that becomes buried at the ligand-protein interface when the C-terminal region in the apo protein assumes the same localised structure as that observed in the wild-type complex.


    Organizational Affiliation

    Protein Structure-Function Research Programme, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glutathione S-transferase A1
A, B
222Homo sapiensMutation(s): 1 
Gene Names: GSTA1
EC: 2.5.1.18
Find proteins for P08263 (Homo sapiens)
Go to Gene View: GSTA1
Go to UniProtKB:  P08263
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GTX
Query on GTX

Download SDF File 
Download CCD File 
A, B
S-HEXYLGLUTATHIONE
C16 H30 N3 O6 S
HXJDWCWJDCOHDG-RYUDHWBXSA-O
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GTXKd: 1300 nM BINDINGMOAD
GTXKd: 1300 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.203 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 99.530α = 90.00
b = 91.472β = 92.40
c = 51.482γ = 90.00
Software Package:
Software NamePurpose
EPMRphasing
REFMACrefinement
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-06-07
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description