Guangxi Key Laboratory of Agro-Environment and Agric-Products Safety, National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning, Guangxi 530004, People's Republic of China.
Guangxi Key Laboratory of Agro-Environment and Agric-Products Safety, National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning, Guangxi 530004, People's Republic of China.
J Hazard Mater. 2023 Aug 15;456:131664. doi: 10.1016/j.jhazmat.2023.131664. Epub 2023 May 18.
Terbuthylazine (TBA) is an emerging environmental contaminant that poses moderate to high risk to non-target organisms. In this study, a newly TBA-degrading strain, Agrobacterium rhizogenes AT13, was isolated. This bacterium degraded 98.7% of TBA (100 mg/L) within 39 h. Based on the six detected metabolites, three novel pathways of strain AT13, including dealkylation, deamination-hydroxylation, and ring-opening reactions, were proposed. The risk assessment demonstrated that most degradation products might be substantially less harmful than TBA. Whole-genome sequencing and RT-qPCR analysis revealed that ttzA, which encodes S-adenosylhomocysteine deaminase (TtzA), is closely related to TBA degradation in AT13. Recombinant TtzA showed 75.3% degradation of 50 mg/L of TBA within 13 h and presented a K value of 0.299 mmol/L and a V value of 0.041 mmol/L/min. The molecular docking results indicated that the binding energy of TtzA to TBA was -32.9 kcal/mol and TtzA residue ASP161 formed two hydrogen bonds with TBA at distances of 2.23 and 1.80 Å. Moreover, AT13 efficiently degraded TBA in water and soil. Overall, this study provides a foundation for the characterization and mechanism of TBA biodegradation and may enhance our understanding of the TBA biodegradation by microbes.
特丁津（TBA）是一种新兴的环境污染物，对非靶标生物具有中等到高风险。在本研究中，分离到一株新的 TBA 降解菌根瘤农杆菌 AT13。该菌在 39 h 内可将 TBA（100 mg/L）降解 98.7%。基于检测到的 6 种代谢产物，提出了 AT13 的 3 条新的降解途径，包括脱烷基化、脱氨-羟化和开环反应。风险评估表明，大多数降解产物可能比 TBA 危害性小得多。全基因组测序和 RT-qPCR 分析表明，编码 S-腺苷同型半胱氨酸脱氨酶（TtzA）的 ttzA 与 AT13 中的 TBA 降解密切相关。重组 TtzA 在 13 h 内可将 50 mg/L 的 TBA 降解 75.3%，其 K 值为 0.299 mmol/L，V 值为 0.041 mmol/L/min。分子对接结果表明，TtzA 与 TBA 的结合能为-32.9 kcal/mol，TtzA 残基 ASP161 与 TBA 形成了两个氢键，距离分别为 2.23 和 1.80 Å。此外，AT13 可有效地在水和土壤中降解 TBA。总之，本研究为 TBA 生物降解的特征和机制提供了基础，可能增强我们对微生物降解 TBA 的理解。
