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 Jun 30:S1674-2052(25)00209-6. doi: 10.1016/j.molp.2025.06.016. Online ahead of print.

Authors

Affiliations

¹ The University of Western Australia, School of Molecular Sciences, 35 Stirling Highway, Crawley, Perth WA 6009, Australia; Curtin University, Centre for Crop and Disease Management, School of Molecular and Life Sciences Kent Street, Bentley, Perth WA 6102, Australia. Electronic address: joel.haywood@curtin.edu.au.
² The University of Western Australia, School of Molecular Sciences, 35 Stirling Highway, Crawley, Perth WA 6009, Australia.
³ The University of Adelaide, Institute for Photonics and Advanced Sensing, (IPAS), School of Biological Sciences, Adelaide, SA 5005, Australia.
⁴ Curtin University, Centre for Crop and Disease Management, School of Molecular and Life Sciences Kent Street, Bentley, Perth WA 6102, Australia.
⁵ The Australian National University, Research School of Biology, Canberra, ACT 2601, Australia.
⁶ Guizhou University, State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, PR China.
⁷ The University of Western Australia, School of Molecular Sciences, 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 Hwy, Crawley, 6009, Australia. Electronic address: joel.haywood@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 antimalarials targeting 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 DHFR-TS is a viable herbicide target.

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