6TO3 image
Entry Detail
PDB ID:
6TO3
Keywords:
Title:
GSTF1 from Alopecurus myosuroides - covalently modified
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2019-12-11
Release Date:
2021-08-18
Method Details:
Experimental Method:
Resolution:
2.80 Å
R-Value Free:
0.28
R-Value Work:
0.20
Space Group:
P 63 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Glutathione transferase
Chain IDs:A (auth: AAA)
Chain Length:305
Number of Molecules:1
Biological Source:Alopecurus myosuroides
Ligand Molecules
Primary Citation
Flavonoid-based inhibitors of the Phi-class glutathione transferase from black-grass to combat multiple herbicide resistance.
Org.Biomol.Chem. 19 9211 9222 (2021)
PMID: 34643629 DOI: 10.1039/d1ob01802g

Abstact

The evolution and growth of multiple-herbicide resistance (MHR) in grass weeds continues to threaten global cereal production. While various processes can contribute to resistance, earlier work has identified the phi class glutathione-S-transferase (AmGSTF1) as a functional biomarker of MHR in black-grass (Alopecurus myosuroides). This study provides further insights into the role of AmGSTF1 in MHR using a combination of chemical and structural biology. Crystal structures of wild-type AmGSTF1, together with two specifically designed variants that allowed the co-crystal structure determination with glutathione and a glutathione adduct of the AmGSTF1 inhibitor 4-chloro-7-nitro-benzofurazan (NBD-Cl) were obtained. These studies demonstrated that the inhibitory activity of NBD-Cl was associated with the occlusion of the active site and the impediment of substrate binding. A search for other selective inhibitors of AmGSTF1, using ligand-fishing experiments, identified a number of flavonoids as potential ligands. Subsequent experiments using black-grass extracts discovered a specific flavonoid as a natural ligand of the recombinant enzyme. A series of related synthetic flavonoids was prepared and their binding to AmGSTF1 was investigated showing a high affinity for derivatives bearing a O-5-decyl-α-carboxylate. Molecular modelling based on high-resolution crystal structures allowed a binding pose to be defined which explained flavonoid binding specificity. Crucially, high binding affinity was linked to a reversal of the herbicide resistance phenotype in MHR black-grass. Collectively, these results present a nature-inspired new lead for the development of herbicide synergists to counteract MHR in weeds.

Legend

Protein

Chemical

Disease

Primary Citation of related structures