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Yu XX, Chen KX, Yuan PP, Wang YH, Li HX, Zhao YX, Dai YJ. Asp-tRNA Asn/Glu-tRNA Gln amidotransferase A subunit-like amidase mediates the degradation of insecticide flonicamid by Variovorax boronicumulans CGMCC 4969. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172479. [PMID: 38621543 DOI: 10.1016/j.scitotenv.2024.172479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/02/2024] [Accepted: 04/12/2024] [Indexed: 04/17/2024]
Abstract
The main metabolic product of the pyridinecarboxamide insecticide flonicamid, N-(4-trifluoromethylnicotinyl)glycinamide (TFNG-AM), has been shown to have very high mobility in soil, leading to its accumulation in the environment. Catabolic pathways of flonicamid have been widely reported, but few studies have focused on the metabolism of TFNG-AM. Here, the rapid transformation of TFNG-AM and production of the corresponding acid product N-(4-trifluoromethylnicotinoyl) glycine (TFNG) by the plant growth-promoting bacterium Variovorax boronicumulans CGMCC 4969 were investigated. With TFNG-AM at an initial concentration of 0.86 mmol/L, 90.70 % was transformed by V. boronicumulans CGMCC 4969 resting cells within 20 d, with a degradation half-life of 4.82 d. A novel amidase that potentially mediated this transformation process, called AmiD, was identified by bioinformatic analyses. The gene encoding amiD was cloned and expressed recombinantly in Escherichia coli, and the enzyme AmiD was characterized. Key amino acid residue Val154, which is associated with the catalytic activity and substrate specificity of signature family amidases, was identified for the first time by homology modeling, structural alignment, and site-directed mutagenesis analyses. When compared to wild-type recombinant AmiD, the mutant AmiD V154G demonstrated a 3.08-fold increase in activity toward TFNG-AM. The activity of AmiD V154G was greatly increased toward aromatic L-phenylalanine amides, heterocyclic TFNG-AM and IAM, and aliphatic asparagine, whereas it was dramatically lowered toward benzamide, phenylacetamide, nicotinamide, acetamide, acrylamide, and hexanamid. Quantitative PCR analysis revealed that AmiD may be a substrate-inducible enzyme in V. boronicumulans CGMCC 4969. The mechanism of transcriptional regulation of AmiD by a member of the AraC family of regulators encoded upstream of the amiD gene was preliminarily investigated. This study deepens our understanding of the mechanisms of metabolism of toxic amides in the environment, providing new ideas for microbial bioremediation.
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Affiliation(s)
- Xue-Xiu Yu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Ke-Xin Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Pan-Pan Yuan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Yu-He Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Hua-Xiao Li
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Yun-Xiu Zhao
- Jiangsu Key Laboratory for Bioresources of Saline Soils, School of Wetlands, Jiangsu Synthetic Innovation Center for Coastal Bioagriculture, Yancheng Teachers University, Yancheng 224007, People's Republic of China.
| | - Yi-Jun Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
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Zhao YX, Yuan J, Song KW, Yin CJ, Chen LW, Yang KY, Yang J, Dai YJ. Efficient Biodegradation of the Neonicotinoid Insecticide Flonicamid by Pseudaminobacter salicylatoxidans CGMCC 1.17248: Kinetics, Pathways, and Enzyme Properties. Microorganisms 2024; 12:1063. [PMID: 38930445 PMCID: PMC11205548 DOI: 10.3390/microorganisms12061063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024] Open
Abstract
Nitrile-containing insecticides can be converted into their amide derivatives by Pseudaminobacter salicylatoxidans. N-(4-trifluoromethylnicotinoyl) glycinamide (TFNG-AM) is converted to 4-(trifluoromethyl) nicotinoyl glycine (TFNG) using nitrile hydratase/amidase. However, the amidase that catalyzes this bioconversion has not yet been fully elucidated. In this study, it was discovered that flonicamid (FLO) is degraded by P. salicylatoxidans into the acid metabolite TFNG via the intermediate TFNG-AM. A half-life of 18.7 h was observed for P. salicylatoxidans resting cells, which transformed 82.8% of the available FLO in 48 h. The resulting amide metabolite, TFNG-AM, was almost all converted to TFNG within 19 d. A novel amidase-encoding gene was cloned and overexpressed in Escherichia coli. The enzyme, PmsiA, hydrolyzed TFNG-AM to TFNG. Despite being categorized as a member of the amidase signature enzyme superfamily, PsmiA only shares 20-30% identity with the 14 previously identified members of this family, indicating that PsmiA represents a novel class of enzyme. Homology structural modeling and molecular docking analyses suggested that key residues Glu247 and Met242 may significantly impact the catalytic activity of PsmiA. This study contributes to our understanding of the biodegradation process of nitrile-containing insecticides and the relationship between the structure and function of metabolic enzymes.
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Affiliation(s)
- Yun-Xiu Zhao
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-Agriculture, School of Wetlands, Yancheng Teachers University, Yancheng 224007, China; (Y.-X.Z.); (K.-W.S.); (C.-J.Y.)
| | - Jing Yuan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, China;
| | - Ke-Wei Song
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-Agriculture, School of Wetlands, Yancheng Teachers University, Yancheng 224007, China; (Y.-X.Z.); (K.-W.S.); (C.-J.Y.)
| | - Chi-Jie Yin
- Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-Agriculture, School of Wetlands, Yancheng Teachers University, Yancheng 224007, China; (Y.-X.Z.); (K.-W.S.); (C.-J.Y.)
| | - Li-Wen Chen
- College of Marine and Biological Engineering, Yancheng Teachers University, Yancheng 224002, China; (L.-W.C.); (K.-Y.Y.)
| | - Kun-Yan Yang
- College of Marine and Biological Engineering, Yancheng Teachers University, Yancheng 224002, China; (L.-W.C.); (K.-Y.Y.)
| | - Ju Yang
- College of Marine and Biological Engineering, Yancheng Teachers University, Yancheng 224002, China; (L.-W.C.); (K.-Y.Y.)
| | - Yi-Jun Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, China;
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Jiang H, Yuan P, Ding J, Wu H, Wang L, Chen K, Jiang N, Dai Y. Novel biodegradation pathway of insecticide flonicamid mediated by an amidase and its unusual substrate spectrum. JOURNAL OF HAZARDOUS MATERIALS 2023; 441:129952. [PMID: 36116312 DOI: 10.1016/j.jhazmat.2022.129952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/20/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
The insecticide flonicamid (FLO) and its main degradation intermediate 4-trifluoromethylnicotinamide (TFNA-AM) are hazardous to the environment and animals. Microbial transformation of FLO has been well studied, but no study has yet reported on TFNA-AM degradation by a microorganism. Here, Pseudomonas stutzeri CGMCC 22915 effectively degraded TFNA-AM to 5-trifluoromethylnicotinic acid (TFNA). P. stutzeri CGMCC 22915 degraded 60.0% of TFNA-AM (1154.44 μmol/L) within 6 h with a half-life of just 4.5 h. Moreover, P. stutzeri CGMCC 22915 significantly promoted TFNA-AM decomposition in surface water. The reaction was catalyzed by an amidase, PsAmiA. PsAmiA is encoded in a novel nitrile-converting enzyme gene cluster. The enzyme shared only 20-44% identities with previously characterized signature amidases. PsAmiA was successfully expressed in Escherichia coli and its enzymatic properties were investigated using TFNA-AM as the substrate. PsAmiA was more active toward amides without hydrophilic groups, and did not hydrolyze another amide metabolite of FLO, N-(4-trifluoromethylnicotinoyl)glycinamide (TFNG-AM), which is structurally very similar to TFNA-AM. Molecular docking of PsAmiA and TFNA-AM indicated that hydrophobic residues Leu148, Ala150, Ala195, Ile225, Trp341, Leu460, and Ile463 may affect its substrate spectrum. This study provides new insights of the environmental fate of FLO at the molecular level and the structure-function relationships of amidases.
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Affiliation(s)
- Huoyong Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Panpan Yuan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Jianjun Ding
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Hongkai Wu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Li Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Kexin Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Nengdang Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
| | - Yijun Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing 210023, People's Republic of China.
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Jiang HY, Jiang ND, Wang L, Guo JJ, Chen KX, Dai YJ. Characterization of nitrilases from Variovorax boronicumulans that functions in insecticide flonicamid degradation and β-cyano-L-alanine detoxification. J Appl Microbiol 2022; 133:311-322. [PMID: 35365856 DOI: 10.1111/jam.15561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/04/2022] [Accepted: 03/28/2022] [Indexed: 11/27/2022]
Abstract
AIMS To characterize the functions of nitrilases of Variovorax boronicumulans CGMCC 4969 and evaluate flonicamid (FLO) degradation and β-cyano-L-alanine (Ala(CN)) detoxification by this bacterium. METHODS AND RESULTS V. boronicumulans CGMCC 4969 nitrilases (NitA and NitB) were purified and substrate specificity assay indicated that both of them degraded insecticide FLO to N-(4-trifluoromethylnicotinoyl)glycinamide (TFNG-AM) and 4-(trifluoromethyl)nicotinol glycine (TFNG). Ala(CN), a plant detoxification intermediate, was hydrolyzed by NitB. Escherichia coli overexpressing NitA and NitB degraded 41.2 and 93.8% of FLO (0.87 mmol·L-1 ) within 1 h, with half-lives of 1.30 and 0.25 h, respectively. NitB exhibited the highest nitrilase activity toward FLO. FLO was used as a substrate to compare their enzymatic properties. NitB was more tolerant to acidic conditions and organic solvents than NitA. Conversely, NitA was more tolerant to metal ions than NitB. CGMCC 4969 facilitated FLO degradation in soil and surface water and utilized Ala(CN) as a sole nitrogen source for growth. CONCLUSIONS CGMCC 4969 efficiently degraded FLO mediated by NitA and NitB; NitB was involved in Ala(CN) detoxification. SIGNIFICANCE AND IMPACT OF THE STUDY This study promotes our understanding of versatile functions of nitrilases from CGMCC 4969 that is promising for environmental remediation.
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Affiliation(s)
- H Y Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
| | - N D Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
| | - L Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
| | - J J Guo
- Nanjing Normal University Zhongbei College, Zhenjiang, People's Republic of China
| | - K X Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
| | - Y J Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
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Zhao YX, Wang L, Chen KX, Jiang ND, Sun SL, Ge F, Dai YJ. Biodegradation of flonicamid by Ensifer adhaerens CGMCC 6315 and enzymatic characterization of the nitrile hydratases involved. Microb Cell Fact 2021; 20:133. [PMID: 34256737 PMCID: PMC8278588 DOI: 10.1186/s12934-021-01620-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Flonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide, FLO) is a new type of pyridinamide insecticide that regulates insect growth. Because of its wide application in agricultural production and high solubility in water, it poses potential risks to aquatic environments and food chain. RESULTS In the present study, Ensifer adhaerens CGMCC 6315 was shown to efficiently transform FLO into N-(4-trifluoromethylnicotinoyl) glycinamide (TFNG-AM) via a hydration pathway mediated by two nitrile hydratases, PnhA and CnhA. In pure culture, resting cells of E. adhaerens CGMCC 6315 degraded 92% of 0.87 mmol/L FLO within 24 h at 30 °C (half-life 7.4 h). Both free and immobilized (by gel beads, using calcium alginate as a carrier) E. adhaerens CGMCC 6315 cells effectively degraded FLO in surface water. PnhA has, to our knowledge, the highest reported degradation activity toward FLO, Vmax = 88.7 U/mg (Km = 2.96 mmol/L). Addition of copper ions could increase the enzyme activity of CnhA toward FLO by 4.2-fold. Structural homology modeling indicated that residue β-Glu56 may be important for the observed significant difference in enzyme activity between PnhA and CnhA. CONCLUSIONS Application of E. adhaerens may be a good strategy for bioremediation of FLO in surface water. This work furthers our understanding of the enzymatic mechanisms of biodegradation of nitrile-containing insecticides and provides effective transformation strategies for microbial remediation of FLO contamination.
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Affiliation(s)
- Yun-Xiu Zhao
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, 210023 People’s Republic of China
| | - Li Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, 210023 People’s Republic of China
| | - Ke-Xin Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, 210023 People’s Republic of China
| | - Neng-Dang Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, 210023 People’s Republic of China
| | - Shi-Lei Sun
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, 221116 People’s Republic of China
| | - Feng Ge
- Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, 210042 People’s Republic of China
| | - Yi-Jun Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, Nanjing, 210023 People’s Republic of China
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