Abstract：
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, Corynebacterium sp. Z-1 was isolated and found to degrade multiple AOPPs, including quizalofop-p-ethyl (QPE), haloxyfop-p-methyl (HPM), fenoxaprop-p-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.
摘要：
酯酶对芳氧基苯氧基丙酸酯除草剂（AOPP）的生物降解至关重要。然而,人们对酯酶降解AOPP的潜在分子机制知之甚少。在目前的工作中,棒状杆菌属。Z-1被分离并发现降解多种AOPP，包括quizalofop-p-乙基（QPE），haloxyfop-p-甲基（HPM），非诺沙丙-对乙基(FPE)，卤化丁基（CYB），和clodinafop-炔丙基（CFP）。一种新颖的酯酶，QfeH,催化AOPP中的酯键断裂形成AOPP酸，从菌株Z-1鉴定。QfeH对AOPP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，定点诱变表明了QfeH介导的不同AOPP降解的催化机理。值得注意的是,关键残基S159对于QfeH的活性是必需的。此外，V222Y,T227M,T227A,A271R,和M275K突变体，表现出比QfeH高2.9-5.0倍的活性，是建造的。这项研究促进了对酯酶对AOPP生物修复的机械理解。
