Anhui Provincial Key Laboratory of Hazardous Factors and Risk Control of Agri-food Quality Safety, College of Resources and Environment, Anhui Agricultural University, Hefei 230036, China.
J Agric Food Chem. 2024 Jul 31;72(30):16877-16888. doi: 10.1021/acs.jafc.4c02786. Epub 2024 Jul 22.
Esterases are crucial for aryloxyphenoxypropionate herbicide (AOPP) biodegradation. However, the underlying molecular mechanisms of AOPP biodegradation by esterases are poorly understood. In the current work, sp. Z-1 was isolated and found to degrade multiple AOPPs, including quizalofop--ethyl (QPE), haloxyfop--methyl (HPM), fenoxaprop--ethyl (FPE), cyhalofop-butyl (CYB), and clodinafop-propargyl (CFP). A novel esterase, QfeH, which catalyzes the cleavage of ester bonds in AOPPs to form AOPP acids, was identified from strain Z-1. The catalytic activities of QfeH toward AOPPs decreased in the following order: CFP > FPE > CYB > QPE > HPM. Molecular docking, computational analyses, and site-directed mutagenesis indicated the catalytic mechanisms of QfeH-mediated degradation of different AOPPs. Notably, the key residue S159 is essential for the activity of QfeH. Moreover, V222Y, T227M, T227A, A271R, and M275K mutants, exhibiting 2.9-5.0 times greater activity than QfeH, were constructed. This study facilitates the mechanistic understanding of AOPPs bioremediation by esterases.
酯酶对于芳氧苯氧丙酸类除草剂（AOPP）的生物降解至关重要。然而，酯酶降解 AOPP 的潜在分子机制仍知之甚少。在本研究中，从 sp. Z-1 中分离得到一株菌，发现其能降解多种 AOPPs，包括精喹禾灵（QPE）、高效氟吡甲禾灵（HPM）、精噁唑禾草灵（FPE）、氰氟草酯（CYB）和炔草酸（CFP）。从菌株 Z-1 中鉴定出一种新型酯酶 QfeH，它能催化 AOPPs 中酯键的断裂，形成 AOPP 酸。QfeH 对 AOPPs 的催化活性按以下顺序降低：CFP > FPE > CYB > QPE > HPM。分子对接、计算分析和定点突变表明了 QfeH 介导不同 AOPPs 降解的催化机制。值得注意的是，关键残基 S159 对 QfeH 的活性至关重要。此外，构建了 V222Y、T227M、T227A、A271R 和 M275K 突变体，它们的活性比 QfeH 高 2.9-5.0 倍。该研究促进了对酯酶介导的 AOPPs 生物修复的机制理解。
