Cheng Yan, Wang Yuan, Lonhienne Thierry, Wang Jian-Guo, Guddat Luke W
School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia.
State-Key Laboratory and Research Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, National Pesticide Engineering Research Center, College of Chemistry, Nankai University, Tianjin 300071, China.
J Agric Food Chem. 2024 Oct 7. doi: 10.1021/acs.jafc.4c04990.
Triasulfuron is a commercial herbicide of the sulfonylurea family. This compound targets acetohydroxyacid synthase (AHAS, E.C. 2.2.1.6), the first enzyme in the branched chain amino acid biosynthesis pathway. Here, we have determined crystal structures of AHAS (AHAS) in complex with triasulfuron and two newly designed herbicidal compounds, identified as FMO and CMO, showing that their binding modes are subtly different. Kinetic studies showed all three compounds exhibit varying values, 0.192 ± 0.013 μM for triasulfuron, 0.086 ± 0.013 μM for FMO, and 1.448 ± 0.058 μM for CMO, but all are strong time-dependent accumulative inhibitors of AHAS. Apart from triasulfuron being a powerful herbicide with application rates of 10-15 g/ha in wheat fields, CMO and FMO are also herbicidal at 7.5-30 g/ha for barnyard grass. This study emphasizes that accumulative inhibition is an important factor that contributes to herbicidal activity.
三氟磺隆是一种磺酰脲类的商业除草剂。该化合物作用于乙酰羟酸合酶（AHAS，E.C. 2.2.1.6），这是支链氨基酸生物合成途径中的首个酶。在此，我们确定了与三氟磺隆以及两种新设计的除草剂化合物（分别鉴定为FMO和CMO）结合的AHAS（乙酰羟酸合酶）的晶体结构，结果表明它们的结合模式存在细微差异。动力学研究表明，这三种化合物均呈现出不同的 值，三氟磺隆为0.192±0.013μM，FMO为0.086±0.013μM，CMO为1.448±0.058μM，但它们都是AHAS的强效时间依赖性累积抑制剂。除了三氟磺隆是一种在麦田中施用量为10 - 15克/公顷的强效除草剂外，CMO和FMO对稗草在7.5 - 30克/公顷的用量下也具有除草活性。这项研究强调累积抑制是促成除草活性的一个重要因素。
