College of Resources and Environment, Anhui Agricultural University, Key Laboratory of Agri-food Safety of Anhui Province, Hefei 230036, China.
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, USA.
J Hazard Mater. 2023 Mar 15;446:130708. doi: 10.1016/j.jhazmat.2022.130708. Epub 2022 Dec 30.
Demethylthio is one of the most important ways for microorganisms to metabolize triazine herbicides. Previous studies have found that the initial reaction of prometryn catabolism in Leucobacter triazinivorans JW-1 was the hydroxylation of its methylthio group, however, the corresponding functional enzyme was not yet clear. In this study, the gene proA was responsible for the initial step of prometryn catabolism from the strain JW-1 was cloned and expressed, and the purified amidohydrolases ProA have the ability to transform prometryn to 2-hydroxypropazine and methanethiol. The optimized reaction temperature and pH of ProA were 45 °C and 7.0, respectively, and the kinetic constants K and V of ProA for the catalysis of prometryn were 32.6 μM and 0.09 μmol/min/mg, respectively. Molecular docking analyses revealed that different catalysis efficiency of ProA and TrzN (Nocardioides sp. C190) for prometryn and atrazine was due to non-covalent changes in amino acid residues. Our findings provide new insights into the understanding of s-triazine catabolism at the molecular level.
去甲基硫是微生物代谢三嗪类除草剂的最重要途径之一。先前的研究发现，在 Leucobacter triazinivorans JW-1 中环丙嘧磺隆代谢的初始反应是其甲基硫基团的羟化，然而，相应的功能酶尚不清楚。在这项研究中，负责 JW-1 菌株中环丙嘧磺隆初始代谢步骤的基因 proA 被克隆和表达，并且纯化的酰胺水解酶 ProA 能够将环丙嘧磺隆转化为 2-羟基丙嗪和甲硫醇。ProA 的最佳反应温度和 pH 值分别为 45°C 和 7.0，ProA 催化环丙嘧磺隆的动力学常数 K 和 V 分别为 32.6 μM 和 0.09 μmol/min/mg。分子对接分析表明，ProA 和 TrzN（Nocardioides sp. C190）对环丙嘧磺隆和莠去津的不同催化效率是由于氨基酸残基的非共价变化。我们的研究结果为在分子水平上理解 s-三嗪代谢提供了新的见解。
