Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 52.04 kDa 
• Atom Count: 4345 
• Residue Count: 440 
• Unique protein chains: 1

2R3X

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

• DOI: 10.2210/pdb2R3X/pdb

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2007-08-30 Released: 2007-12-18 
• Deposition Author(s): Burke, J.P.W.G., Kinsley, N., Sayed, M., Sewell, T., Dirr, H.W.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.259 
• R-Value Work: 0.192 
• R-Value Observed: 0.195 

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

• PubMed: 19959275 
• DOI: 10.1016/j.bpc.2009.11.003
• Primary Citation of Related Structures:  
  2R3X


• 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 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.

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Organizational Affiliation: 

University of the Witwatersrand, Johannesburg, South Africa.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Glutathione S-transferase A1	A, B	222	Homo sapiens	Mutation(s): 1  Gene Names: GSTA1 EC: 2.5.1.18 (PDB Primary Data), 1.11.1 (UniProt), 5.3.3 (UniProt)
Find proteins for P08263 (Homo sapiens) Explore P08263  Go to UniProtKB:  P08263
NIH Common Fund Data Resources
PHAROS:  P08263 GTEx:  ENSG00000243955

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
GTX	A, B	S-HEXYLGLUTATHIONE C16 H30 N3 O6 S HXJDWCWJDCOHDG-RYUDHWBXSA-O

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.259 
• R-Value Work: 0.192 
• R-Value Observed: 0.195 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 99.103	α = 90
b = 93.858	β = 93.9
c = 51.566	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
MOLREP	phasing
REFMAC	refinement
PDB_EXTRACT	data extraction
HKL-2000	data collection

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2007-08-30 
• Released Date: 2007-12-18 
Deposition Author(s): Burke, J.P.W.G., Kinsley, N., Sayed, M., Sewell, T., Dirr, H.W.

Revision History 

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