He Bo, Hu Yanhao, Liu Dongshan, Zang Xin, He Xu, Chen Wang, Yang Jingfang, Feng Mingfeng, Chen Ping, Wei Lirong, Li Yu, Yan Wei, Li Jun, Feng Zhike, Zhou Jiahai, Ye Yonghao
State Key Laboratory of Agricultural and Forestry Biosecurity, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
State Key Laboratory of Chemical Biology, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, Shanghai, 200032, China.
Nat Commun. 2025 Jun 4;16(1):5205. doi: 10.1038/s41467-025-60489-8.
Dihydroxyacid dehydratase (DHAD), a key enzyme in branched-chain amino acid synthesis in plants, is a promising yet unexploited herbicide target. Inspired by the natural DHAD inhibitor aspterric acid, we design benzoxazinone derivatives with α-hydroxycarboxylic acid moieties as potential inhibitors and develop an eco-friendly α-C(sp³)-H hydroxylation method for accessing carbonyl compounds. Among the derivatives, 7-fluoro-2-hydroxy-3-oxo-4-propyne-3,4-dihydro-2H-benzo[b][1,4]oxazine-2-carboxylic acid (I-6e) completely inhibits Arabidopsis thaliana germination and suppress six weed species by > 50%, with 100% efficacy against Avena fatua and Setaria viridis at 150 g ai/ha. This broad-spectrum activity and rice crop safety highlight its potential as an herbicide lead compound. Compound I-6e exhibits stronger affinity for DHAD (K = 1 µM) than that of the natural substrate (K = 5.39 µM). The 2.19 Å cocrystal structure of the AtDHAD-I-6e complex reveals a unique binding mechanism, confirming the critical role of the α-hydroxycarboxylic acid scaffold. This study provides a blueprint for rational DHAD inhibitor design.
二羟基酸脱水酶（DHAD）是植物支链氨基酸合成中的关键酶，是一个有前景但尚未开发的除草剂作用靶标。受天然DHAD抑制剂阿斯特酸的启发，我们设计了带有α-羟基羧酸部分的苯并恶嗪酮衍生物作为潜在抑制剂，并开发了一种用于制备羰基化合物的环境友好型α-C(sp³)-H羟基化方法。在这些衍生物中，7-氟-2-羟基-3-氧代-4-丙炔基-3,4-二氢-2H-苯并[b][1,4]恶嗪-2-羧酸（I-6e）完全抑制拟南芥萌发，并使六种杂草的抑制率超过50%，在150 g ai/ha剂量下对野燕麦和狗尾草的防效达100%。这种广谱活性和对水稻作物的安全性突出了其作为除草剂先导化合物的潜力。化合物I-6e对DHAD的亲和力（K = 1 µM）比天然底物（K = 5.39 µM）更强。AtDHAD-I-6e复合物的2.19 Å共晶体结构揭示了一种独特的结合机制，证实了α-羟基羧酸支架的关键作用。本研究为合理设计DHAD抑制剂提供了蓝图。
