Structural insights into a plant-conserved DHFR-TS reveal a selective herbicide target

Joel Haywood; Karen J Breese; Daniel P McDougal; Callum Verdonk; Abigail Partridge; Adrian F Lo; Jingjing Zhang; Wen-Chao Yang; John B Bruning; Kevin J Saliba; Charles S Bond; Keith A Stubbs; Joshua S Mylne

doi:10.1016/j.molp.2025.06.016

Structural insights into a plant-conserved DHFR-TS reveal a selective herbicide target

Mol Plant. 2025 Aug 4;18(8):1294-1309. doi: 10.1016/j.molp.2025.06.016. Epub 2025 Jun 30.

Authors

Affiliations

¹ School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia; Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Perth, WA 6102, Australia. Electronic address: joel.haywood@curtin.edu.au.
² School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia.
³ Institute for Photonics and Advanced Sensing, (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.
⁴ Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Perth, WA 6102, Australia.
⁵ Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia.
⁶ State Key Laboratory of Green Pesticide, Center for R&D of Fine Chemicals of Guizhou University, Guizhou University, Guiyang 550025, China.
⁷ School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia; ARC Training Centre for Next-Gen Technologies in Biomedical Analysis, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia. Electronic address: keith.stubbs@uwa.edu.au.
⁸ School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia; Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Perth, WA 6102, Australia. Electronic address: josh.mylne@curtin.edu.au.

PMID: 40598768
DOI: 10.1016/j.molp.2025.06.016

Abstract

Modern agricultural practices rely on herbicides to reduce yield losses. Herbicide-resistant weeds threaten herbicide utility and, hence, food security. New herbicide modes of action and integrated pest-management practices are vital to mitigate this threat. As the antimalarials that target the bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) have been shown to be herbicidal, DHFR-TS might represent a mode-of-action target for the development of herbicides. Here, we present the crystal structure of a DHFR-TS (AtDHFR-TS1) from the model dicot Arabidopsis thaliana. It shows a divergent DHFR active site and a linker domain that challenges previous classifications of bifunctional DHFR-TS proteins. This plant-conserved architecture enabled us to develop highly selective herbicidal inhibitors of AtDHFR-TS1 over human DHFR and identify inhibitors with unique scaffolds via a large-library virtual screen. These results suggest that DHFR-TS is a viable herbicide target.

Keywords: dihydrofolate reductase; herbicide; protein structure; thymidylate synthase.

MeSH terms

Arabidopsis Proteins* / chemistry
Arabidopsis Proteins* / metabolism
Arabidopsis* / drug effects
Arabidopsis* / enzymology
Herbicides* / chemistry
Herbicides* / pharmacology
Humans
Models, Molecular
Tetrahydrofolate Dehydrogenase* / chemistry
Tetrahydrofolate Dehydrogenase* / metabolism
Thymidylate Synthase* / antagonists & inhibitors
Thymidylate Synthase* / chemistry
Thymidylate Synthase* / metabolism

Substances

Tetrahydrofolate Dehydrogenase
Herbicides
Thymidylate Synthase
Arabidopsis Proteins