2R3X

Crystal structure of an R15L hGSTA1-1 mutant complexed with S-hexyl-glutathione


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Arginine 15 stabilizes an S(N)Ar reaction transition state and the binding of anionic ligands at the active site of human glutathione transferase A1-1.

Gildenhuys, S.Dobreva, M.Kinsley, N.Sayed, Y.Burke, J.Pelly, S.Gordon, G.P.Sayed, M.Sewell, T.Dirr, H.W.

(2010) Biophys.Chem. 146: 118-125

  • DOI: 10.1016/j.bpc.2009.11.003

  • PubMed Abstract: 
  • Arg15, conserved in class Alpha GSTs (glutathione transferases), is located at the interface between the G- and H-sites of the active site where its cationic guanidinium group might play a role in catalysis and ligand binding. Arg15 in human GSTA1-1 ...

    Arg15, conserved in class Alpha GSTs (glutathione transferases), is located at the interface between the G- and H-sites of the active site where its cationic guanidinium group might play a role in catalysis and ligand binding. Arg15 in human GSTA1-1 was replaced with a leucine and crystallographic, spectroscopic, thermodynamic and molecular docking methods were used to investigate the contribution made by Arg15 towards (i) the binding of glutathione (GSH) to the G-site, (ii) the pK(a) of the thiol group of GSH, (iii) the stabilization of an analog of the anionic transition state of the S(N)Ar reaction between 1-chloro-2,4-dinitrobenzene (CDNB) and GSH, and, (iv) the binding of the anionic non-substrate ligand 8-anilino-1-naphthalene sulphonate (ANS) to the H-site. While the R15L mutation substantially diminishes the CDNB-GSH conjugating activity of the enzyme, it has little effect on protein structure and stability. Arg15 does not contribute significantly towards the enzyme's affinity for GSH but does determine the reactivity of GSH by reducing the thiol's pK(a) from 7.6 to 6.6. The anionic sigma-complex formed between GSH and 1,3,5-trinitrobenzene is stabilized by Arg15, suggesting that it also stabilizes the transition state formed in the S(N)Ar reaction between GSH and CDNB. The trinitrocyclohexadienate moiety of the sigma-complex binds the H-site where the catalytic residue, Tyr9, was identified to hydrogen bond to an o-nitro group of the sigma-complex. The affinity for ANS at the H-site is decreased about 3-fold by the R15L mutation implicating the positive electrostatic potential of Arg15 in securing the organic anion at this site.


    Organizational Affiliation

    University of the Witwatersrand, Johannesburg, 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
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.192 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 99.103α = 90.00
b = 93.858β = 93.90
c = 51.566γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
HKL-2000data collection
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
REFMACrefinement
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-12-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-10-25
    Type: Refinement description