1
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Zhang X, Ma X, Dai G, Fu X, Zhou Y. Efficient Secretory Expression and Purification on Three Insoluble Amidohydrolases for Ochratoxin A Hydrolysis by Pichia pastoris. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:16403-16411. [PMID: 39004912 DOI: 10.1021/acs.jafc.4c03804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
As a highly toxic mycotoxin, ochratoxin A (OTA) is widely contaminating agricultural products and has various toxicological effects. Bioenzymes for OTA degradation have shown promising potential for detoxification. Other than the efficient amidohydrolase ADH3 previously, two novel amidohydrolases ADH1 and AMD3 were obtained in this study. During Escherichia coli expression, the expressed protein solubility was very low and will limit future industrial application. Here, high copy number integrations were screened, and the amidohydrolases were efficiently secretory expressed by Pichia pastoris GS115. The protein yields from 1.0 L of fermentation supernatant were 53.5 mg for ADH1, 89.15 mg for ADH3, and 79.5 mg for AMD3. The catalytic efficiency (Kcat/Km) of secretory proteins was 124.95 s-1 mM-1 for ADH3, 123.21 s-1 mM-1 for ADH1, and 371.99 s-1 mM-1 for AMD3. In comparison to E. coli expression, the active protein yields substantially increased 15.78-51.53 times. Meanwhile, two novel amidohydrolases (ADH1 and AMD3) showed much higher activity than ADH3 that produced by secretory expression.
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Affiliation(s)
- Xuanjun Zhang
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science Technology, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
- School of Life Science, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Xue Ma
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science Technology, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
- School of Life Science, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Guangqing Dai
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science Technology, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Xiaojie Fu
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science Technology, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Yu Zhou
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science Technology, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
- Joint Research Center for Food Nutrition and Health of lHM, Hefei, Anhui 230036, People's Republic of China
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2
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Fu X, Fei Q, Zhang X, Li N, Zhang L, Zhou Y. Two different types of hydrolases co-degrade ochratoxin A in a highly efficient degradation strain Lysobacter sp. CW239. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134716. [PMID: 38797074 DOI: 10.1016/j.jhazmat.2024.134716] [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: 02/13/2024] [Revised: 05/06/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Ochratoxin A (OTA) is a toxic secondary metabolite that widely contaminates agro-products and poses a significant dietary risk to human health. Previously, a carboxypeptidase CP4 was characterized for OTA degradation in Lysobacter sp. CW239, but the degradation activity was much lower than its host strain CW239. In this study, an amidohydrolase ADH2 was screened for OTA hydrolysis in this strain. The result showed that 50 μg/L OTA was completely degraded by 1.0 μg/mL rADH2 within 5 min, indicating ultra-efficient activity. Meanwhile, the two hydrolases (i.e., CP4 and ADH2) in the strain CW239 showed the same degradation manner, which transformed the OTA to ochratoxin α (OTα) and l-β-phenylalanine. Gene mutants (Δcp4, Δadh2 and Δcp4-adh2) testing result showed that OTA was co-degraded by carboxypeptidase CP4 and amidohydrolase ADH2, and the two hydrolases are sole agents in strain CW239 for OTA degradation. Hereinto, the ADH2 was the overwhelming efficient hydrolase, and the two types of hydrolases co-degraded OTA in CW239 by synergistic effect. The results of this study are highly significant to ochratoxin A contamination control during agro-products production and postharvest.
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Affiliation(s)
- Xiaojie Fu
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Heifei 230036, China
| | - Qingru Fei
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Heifei 230036, China
| | - Xuanjun Zhang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Heifei 230036, China
| | - Na Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Heifei 230036, China
| | - Liang Zhang
- School of Tea and Food Science Technology, Anhui Agricultural University, Heifei 230036, China
| | - Yu Zhou
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Heifei 230036, China; School of Tea and Food Science Technology, Anhui Agricultural University, Heifei 230036, China; Joint Research Center for Food Nutrition and Health of lHM, Hefei 230036, China.
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3
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Zhang L, Zhang X, Chen X, Zhang W, Zhao L, Wang Z, Guo Y. Biodegradation of ochratoxin A by Brevundimonas diminuta HAU429: Characterized performance, toxicity evaluation and functional enzymes. Food Res Int 2024; 187:114409. [PMID: 38763660 DOI: 10.1016/j.foodres.2024.114409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 04/17/2024] [Accepted: 04/20/2024] [Indexed: 05/21/2024]
Abstract
Ochratoxin A (OTA) is a notorious mycotoxin commonly contaminating food products worldwide. In this study, an OTA-degrading strain Brevundimonas diminuta HAU429 was isolated by using hippuryl-L-phenylalanine as the sole carbon source. The biodegradation of OTA by strain HAU429 was a synergistic effect of intracellular and extracellular enzymes, which transformed OTA into ochratoxin α (OTα) through peptide bond cleavage. Cytotoxicity tests and cell metabolomics confirmed that the transformation of OTA into OTα resulted in the detoxification of its hepatotoxicity since OTA but not OTα disturbed redox homeostasis and induced oxidative damage to hepatocytes. Genome mining identified nine OTA hydrolase candidates in strain HAU429. They were heterologously expressed in Escherichia coli, and three novel amidohydrolase BT6, BT7 and BT9 were found to display OTA-hydrolyzing activity. BT6, BT7 and BT9 showed less than 45 % sequence identity with previously identified OTA-degrading amidohydrolases. BT6 and BT7 shared 60.9 % amino acid sequence identity, and exhibited much higher activity towards OTA than BT9. BT6 and BT7 could completely degrade 1 μg mL-1 of OTA within 1 h and 50 min, while BT9 hydrolyzed 100 % of OTA in the reaction mixture by 12 h. BT6 was the most thermostable retaining 38 % of activity after incubation at 70 °C for 10 min, while BT7 displayed the highest tolerance to ethanal remaining 76 % of activity in the presence of 6 % ethanol. This study could provide new insights towards microbial OTA degradation and promote the development of enzyme-catalyzed OTA detoxification during food processing.
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Affiliation(s)
- Liangyu Zhang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Xingke Zhang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Xiaoxue Chen
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Wei Zhang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Lihong Zhao
- College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Zhixiang Wang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Yongpeng Guo
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China.
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Sánchez-Arroyo A, Plaza-Vinuesa L, de Las Rivas B, Mancheño JM, Muñoz R. Structural and functional analysis of the key enzyme responsible for the degradation of ochratoxin A in the Alcaligenes genus. Int J Biol Macromol 2024; 267:131342. [PMID: 38574921 DOI: 10.1016/j.ijbiomac.2024.131342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/01/2024] [Accepted: 04/01/2024] [Indexed: 04/06/2024]
Abstract
The potential to degrade ochratoxin A (OTA), a highly poisonous mycotoxin, was investigated in cultures from Alcaligenes-type strains. Genome sequence analyses from different Alcaligenes species have permitted us to demonstrate a direct, causal link between the gene coding a known N-acyl-L-amino acid amidohydrolase from A. faecalis (AfOTH) and the OTA-degrading activity of this bacterium. In agreement with this finding, we found the gene coding AfOTH in two additional species included in the Alcaligenes genus, namely, A. pakistanensis, and A. aquatilis, which also degraded OTA. Notably, A. faecalis subsp. faecalis DSM 30030T was able to transform OTα, the product of OTA hydrolysis. AfOTH from A. faecalis subsp. phenolicus DSM 16503T was recombinantly over-produced and enzymatically characterized. AfOTH is a Zn2+-containing metalloenzyme that possesses structural features and conserved residues identified in the M20D family of enzymes. AfOTH is a tetramer in solution that shows both aminoacylase and carboxypeptidase activities. Using diverse potential substrates, namely, N-acetyl-L-amino acids and carbobenzyloxy-L-amino acids, a marked preference towards C-terminal Phe and Tyr residues could be deduced. The structural basis for this specificity has been determined by in silico molecular docking analyses. The amidase activity of AfOTH on C-terminal Phe residues structurally supports its OTA and OTB degradation activity.
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Affiliation(s)
- Ana Sánchez-Arroyo
- Bacterial Biotechnology Laboratory, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040 Madrid, Spain
| | - Laura Plaza-Vinuesa
- Bacterial Biotechnology Laboratory, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040 Madrid, Spain
| | - Blanca de Las Rivas
- Bacterial Biotechnology Laboratory, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040 Madrid, Spain
| | - José Miguel Mancheño
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry Blas Cabrera (IQF), CSIC, Serrano 119, 28006 Madrid, Spain.
| | - Rosario Muñoz
- Bacterial Biotechnology Laboratory, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040 Madrid, Spain.
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Yang Y, Zhong W, Wang Y, Yue Z, Zhang C, Sun M, Wang Z, Xue X, Gao Q, Wang D, Zhang Y, Zhang J. Isolation, identification, degradation mechanism and exploration of active enzymes in the ochratoxin A degrading strain Acinetobacter pittii AP19. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133351. [PMID: 38150759 DOI: 10.1016/j.jhazmat.2023.133351] [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: 08/23/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 12/29/2023]
Abstract
Ochratoxin A (OTA) is a polyketide mycotoxin that commonly contaminates agricultural products and causes significant economic losses. In this study, the efficient OTA-degrading strain AP19 was isolated from vineyard soil and was identified as Acinetobacter pittii. Compared with growth in nutrient broth supplemented with OTA (OTA-NB), strain AP19 grew faster in nutrient broth (NB), but the ability of the resulting cell lysates to remove OTA was weaker. After cultivation in NB, the cell lysate of strain AP19 was able to remove 100% of 1 mg/L OTA within 18 h. The cell lysate fraction > 30 kDa degraded 100% of OTA within 12 h, while the fractions < 30 kDa were practically unable to degrade OTA. Further anion exchange chromatography of the > 30 kDa fraction yielded two peaks exhibiting significant OTA degradation activity. The degradation product was identified as OTα. Amino acid metabolism exhibited major transcriptional trends in the response of AP19 to OTA. The dacC gene encoding carboxypeptidase was identified as one of the contributors to OTA degradation. Soil samples inoculated with strain AP19 showed significant OTA degradation. These results provide significant insights into the discovery of novel functions in A. pittii, as well as its potential as an OTA decomposer.
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Affiliation(s)
- Yan Yang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Weitong Zhong
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Yanning Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Zhiwen Yue
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Chen Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Mi Sun
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Zhao Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xianli Xue
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Qiang Gao
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Depei Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ying Zhang
- College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Jian Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China.
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Sánchez-Arroyo A, Plaza-Vinuesa L, Abeijón-Mukdsi MC, de Las Rivas B, Mancheño JM, Muñoz R. A new and promiscuous α/β hydrolase from Acinetobacter tandoii DSM 14970 T inactivates the mycotoxin ochratoxin A. Appl Microbiol Biotechnol 2024; 108:230. [PMID: 38393350 PMCID: PMC10891195 DOI: 10.1007/s00253-024-13073-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/11/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024]
Abstract
The presence of ochratoxin A (OTA) in food and feed represents a serious concern since it raises severe health implications. Bacterial strains of the Acinetobacter genus hydrolyse the amide bond of OTA yielding non-toxic OTα and L-β-phenylalanine; in particular, the carboxypeptidase PJ15_1540 from Acinetobacter sp. neg1 has been identified as an OTA-degrading enzyme. Here, we describe the ability to transform OTA of cell-free protein extracts from Acinetobacter tandoii DSM 14970 T, a strain isolated from sludge plants, and also report on the finding of a new and promiscuous α/β hydrolase (ABH), with close homologs highly distributed within the Acinetobacter genus. ABH from A. tandoii (AtABH) exhibited amidase activity against OTA and OTB mycotoxins, as well as against several carboxypeptidase substrates. The predicted structure of AtABH reveals an α/β hydrolase core composed of a parallel, six-stranded β-sheet, with a large cap domain similar to the marine esterase EprEst. Further biochemical analyses of AtABH reveal that it is an efficient esterase with a similar specificity profile as EprEst. Molecular docking studies rendered a consistent OTA-binding mode. We proposed a potential procedure for preparing new OTA-degrading enzymes starting from promiscuous α/β hydrolases based on our results. KEY POINTS: • AtABH is a promiscuous αβ hydrolase with both esterase and amidohydrolase activities • AtABH hydrolyses the amide bond of ochratoxin A rendering nontoxic OTα • Promiscuous αβ hydrolases are a possible source of new OTA-degrading enzymes.
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Affiliation(s)
- Ana Sánchez-Arroyo
- Bacterial Biotechnology, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040, Madrid, Spain
| | - Laura Plaza-Vinuesa
- Bacterial Biotechnology, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040, Madrid, Spain
| | - María Claudia Abeijón-Mukdsi
- Bacterial Biotechnology, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040, Madrid, Spain
| | - Blanca de Las Rivas
- Bacterial Biotechnology, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040, Madrid, Spain
| | - José Miguel Mancheño
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry Blas Cabrera, CSIC, Serrano 119, 28006, Madrid, Spain.
| | - Rosario Muñoz
- Bacterial Biotechnology, Institute of Food Science, Technology and Nutrition (ICTAN), CSIC, José Antonio Novais 6, 28040, Madrid, Spain.
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Hu Y, Yang X, Tai B, Wang G, Zhang X, Yin Y, Xing F. Bacillus amyloliquefaciens A-1 inhibiting fungal spoilage in agricultural products is improved by metabolic engineering of enhancing surfactin yield. Food Res Int 2024; 175:113752. [PMID: 38129052 DOI: 10.1016/j.foodres.2023.113752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023]
Abstract
Fungi and subsequent mycotoxins contamination in agricultural products have caused enormous losses and great harm to human and animal health. Biological control has attracted the attention of researchers due to its advantages, including mild conditions, low cost, high efficiency and low nutrient loss. In this study, a newly isolated strain Bacillus amyloliquefaciens A-1 (A-1), was screened for its ability to inhibit the growth and Aflatoxin B1 (AFB1) production of Aspergillus flavus NRRL 3357. Electron microscopy results revealed that mycelium and conidia of A. flavus were destroyed by A-1, affecting hyphae, cell walls, cell membranes and organelles. RNA-seq analysis indicated disturbance in gene expression profiles of A. flavus, including amino acid degradation and starch and sucrose metabolism pathways. Importantly, the biosynthesis of AFB1 was significantly inhibited by the down-regulation of key regulatory genes, aflR and aflS, and the simultaneous down-regulation of most structural genes. Genome analysis predicted six secondary metabolites biosynthetic gene clusters. Then, four surfactin synthesized by cluster C were identified as the main active substance of A-1 using HPLC-Q-TOF-MS. The addition of alanine, threonine, Fe2+ increased surfactin production. Notably, the overexpression of comX also improved surfactin production. The vivo test results indicated that A-1 could significantly inhibit the decay of pear by Aspergillus westerdijkiae, and the mildew of maize and peanuts. Especially, the overexpression of comX in A-1 could enhance the inhibitory activity. In conclusion, the inhibition mechanism of A-1 was revealed, and comX was found can improve the production of surfactin and subsequent activities, which provides the scientific basis for the development of biocontrol agents to reduce spoilage in agricultural products.
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Affiliation(s)
- Yafan Hu
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Xu Yang
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Bowen Tai
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Gang Wang
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
| | - Xinlong Zhang
- Shandong Xinfurui Agricultural Science and Technology Co., Ltd. Liaocheng 252000, PR China
| | - Yixuan Yin
- Shandong Xinfurui Agricultural Science and Technology Co., Ltd. Liaocheng 252000, PR China
| | - Fuguo Xing
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
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Dai L, Niu D, Huang JW, Li X, Shen P, Li H, Xie Z, Min J, Hu Y, Yang Y, Guo RT, Chen CC. Cryo-EM structure and rational engineering of a superefficient ochratoxin A-detoxifying amidohydrolase. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131836. [PMID: 37331057 DOI: 10.1016/j.jhazmat.2023.131836] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/09/2023] [Accepted: 06/10/2023] [Indexed: 06/20/2023]
Abstract
Ochratoxin A (OTA) is among the most prevalent mycotoxins detected in agroproducts, posing serious threats to human and livestock health. Using enzymes to conduct OTA detoxification is an appealing potential strategy. The recently identified amidohydrolase from Stenotrophomonas acidaminiphila, termed ADH3, is the most efficient OTA-detoxifying enzyme reported thus far and can hydrolyze OTA to nontoxic ochratoxin α (OTα) and L-β-phenylalanine (Phe). To elucidate the catalytic mechanism of ADH3, we solved the single-particle cryo-electron microscopy (cryo-EM) structures of apo-form, Phe- and OTA-bound ADH3 to an overall resolution of 2.5-2.7 Å. The role of OTA-binding residues was investigated by structural, mutagenesis and biochemical analyses. We also rationally engineered ADH3 and obtained variant S88E, whose catalytic activity was elevated by 3.7-fold. Structural analysis of variant S88E indicates that the E88 side chain provides additional hydrogen bond interactions to the OTα moiety. Furthermore, the OTA-hydrolytic activity of variant S88E expressed in Pichia pastoris is comparable to that of Escherichia coli-expressed enzyme, revealing the feasibility of employing the industrial yeast strain to produce ADH3 and its variants for further applications. These results unveil a wealth of information about the catalytic mechanism of ADH3-mediated OTA degradation and provide a blueprint for rational engineering of high-efficiency OTA-detoxifying machineries.
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Affiliation(s)
- Longhai Dai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Du Niu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jian-Wen Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Xian Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Panpan Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Hao Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Zhenzhen Xie
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jian Min
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yumei Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Rey-Ting Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
| | - Chun-Chi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
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