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Poudel PB, Dhakal D, Lee JC, Sohng JK. Functional characterization of a naphthalene-O-methyltransferase from Nocardia sp. CS682. Enzyme Microb Technol 2024; 172:110351. [PMID: 37939423 DOI: 10.1016/j.enzmictec.2023.110351] [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: 07/18/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Methylation plays important roles in biosynthesis, metabolism, signal transduction, detoxification, protein sorting and repair, and nucleic acid processing. Generally the methyltransferases transfer methyl groups in various natural products using S-adenosyl methionine (SAM) as a cofactor. In this study, we examined and functionally characterized ThnM3 (enzyme), by testing various substrates with different chemical structures. Among the tested substrates, 1,8-dihydroxynaphthalene was the best substrate for methylation. Whole-cell biotransformation was performed using the enzyme in engineered Escherichia coli to produce 8-methoxynaphthalene-1-ol, and 1,8-dimethoxynaphthalene derivatives of 1,8-dihydroxynaphthalene. The products were confirmed using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopic analyses. Therefore, this study is the first to amplify, express the thnM3 (gene), and functionally characterize theThnM3, which exhibits the regioselective modifications of 1,8-dihydroxynaphthalene.
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Affiliation(s)
- Purna Bahadur Poudel
- Institute of Biomolecule Reconstruction (iBR), Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sun Moon-ro 221, Tangjeong-myeon, Asan-si, Chungnam 31460, South Korea
| | - Dipesh Dhakal
- Institute of Biomolecule Reconstruction (iBR), Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sun Moon-ro 221, Tangjeong-myeon, Asan-si, Chungnam 31460, South Korea
| | - Jong Cheol Lee
- Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, Chungnam 31460, South Korea
| | - Jae Kyung Sohng
- Institute of Biomolecule Reconstruction (iBR), Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sun Moon-ro 221, Tangjeong-myeon, Asan-si, Chungnam 31460, South Korea; Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, Chungnam 31460, South Korea.
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2
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Wang J, Liao N, Liu G, Li Y, Xu F, Shi J. Diversity and regioselectivity of O-methyltransferases catalyzing the formation of O-methylated flavonoids. Crit Rev Biotechnol 2023:1-23. [PMID: 38035668 DOI: 10.1080/07388551.2023.2280755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 10/17/2023] [Indexed: 12/02/2023]
Abstract
Flavonoids and their methylated derivatives have immense market potential in the food and biomedical industries due to their multiple beneficial effects, such as antimicrobial, anti-inflammatory, and anticancer activities. The biological synthesis of flavonoids and their derivatives is often accomplished via the use of genetically modified microorganisms to ensure large-scale production. Therefore, it is pivotal to understand the properties of O-methyltransferases (OMTs) that mediate the methylation of flavonoids. However, the properties of these OMTs are governed by their: sources, substrate specificity, amino acid residues in the active sites, and the intricate mechanism. In order to obtain a clue for the selection of suitable OMTs for the biosynthesis of a target methylated flavonoid, we made a comprehensive review of the currently reported results, with a particular focus on their comparative regioselectivity for different flavonoid substrates. Additionally, the possible mechanisms for the diversity of this class of enzymes were explored using molecular simulation technology. Finally, major gaps in our understanding and areas for future studies were discussed. The findings of this study may be useful in selecting genes that encode OMTs and designing enzyme-based processes for synthesizing O-methylated flavonoids.
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Affiliation(s)
- Juan Wang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
| | - Ning Liao
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
| | - Guanwen Liu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
| | - Yinghui Li
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
| | - Fengqin Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
| | - Junling Shi
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, People's Republic of China
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3
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Wu X, Yuwen M, Pu Z, Zhao Z, Yu H, Zha J. Engineering of flavonoid 3'-O-methyltransferase for improved biosynthesis of chrysoeriol in Escherichia coli. Appl Microbiol Biotechnol 2023; 107:1663-1672. [PMID: 36719434 DOI: 10.1007/s00253-023-12403-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 02/01/2023]
Abstract
O-Methylation catalyzed by O-methyltransferases (OMTs) is an important modification of flavonoids for improving the transport efficiency across membranes and metabolic stability in mammalian cells. Chrysoeriol, also known as 3'-O-methylated luteolin, is a methylated flavonoid compound with health-promoting activities. The generation of chrysoeriol from luteolin can be catalyzed by a rice-derived 3'-OMT named ROMT-9, which has a high regiospecificity and activity toward flavonoids in vitro. Herein, we explored the potential of ROMT-9 for in vivo biosynthesis of chrysoeriol in Escherichia coli and adopted semi-rational enzyme engineering guided by homology modeling and molecular docking to improve the bio-production. Two positive variants including L34Q and W284A were obtained which promoted chrysoeriol formation to more than 85 mg/L from 200 mg/L of luteolin in 24 h compared with a titer of 55 mg/L for the strain expressing the native enzyme. Further biochemical analysis confirmed that such improvement in production stemmed from a higher enzyme expression level for the L34Q variant and higher efficiency in substrate binding and catalysis for the W284A variant. This study provides some insights into the engineering of other flavonoid OMTs and will facilitate high-level biosynthesis of methylated flavonoids in engineered microorganisms. KEY POINTS: • Biosynthesis of chrysoeriol from luteolin in E. coli using ROMT-9 • Engineering of ROMT-9 for better bio-production • ROMT-9 variants promote production via better expression or better catalysis.
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Affiliation(s)
- Xia Wu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, Shaanxi, China
| | - Miaomiao Yuwen
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, Shaanxi, China
| | - Zhongji Pu
- Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311200, Zhejiang, China
| | - Zhen Zhao
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, Shaanxi, China
| | - Haoran Yu
- Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311200, Zhejiang, China. .,Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China.
| | - Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, Shaanxi, China.
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4
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Xie L, Lu Y, Zhou Y, Hao X, Chen W. Functional Analysis of a Methyltransferase Involved in Anthocyanin Biosynthesis from Blueberries ( Vaccinium corymbosum). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:16253-16262. [PMID: 36519893 DOI: 10.1021/acs.jafc.2c06743] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Anthocyanins are natural water-soluble pigments that widely exist in plants, with various biological activities, including antioxidant, anti-obesity, and anti-diabetic activities. Currently, monomeric anthocyanins are mainly obtained through natural sources, which limits their availability. In the biosynthesis of anthocyanins, anthocyanin methyltransferases are recognized to play important roles in the water solubility and structural stability of anthocyanins. Blueberries are a rich source of anthocyanins with more than 30 chemical structures. However, the enzymes that were responsible for the methylation of anthocyanidin cores in blueberries had not been reported. Here, blueberries (Vaccinium corymbosum) have been selected as the candidate for characterization of the key enzyme. Phylogenic analysis, enzymatic activity assay, homology modeling, molecular simulation, protein expression and purification assay, site-directed mutation, isothermal titration calorimetry assay, and enzyme kinetic assay were used to identify the enzymatic function and molecular mechanism of VcOMT, which was responsible for the methylation of anthocyanidin cores. VcOMT could use delphinidin as a substrate but not cyanidin, petunidin, anthocyanins, flavonols, and flavonol glycosides. Ile191 and Glu198 were both identified as important amino acid residues for the binding interactions of anthocyanidins with VcOMT.
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Affiliation(s)
- Lianghua Xie
- Department of Traditional Chinese Medicine, Sir Run Yi yang Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Yang Lu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Yiyang Zhou
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Xin Hao
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Wei Chen
- Department of Traditional Chinese Medicine, Sir Run Yi yang Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
- Ningbo Innovation Center, Zhejiang University, Ningbo 315100, China
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Wu K, Moore JA, Miller MD, Chen Y, Lee C, Xu W, Peng Z, Duan Q, Phillips GN, Uribe RA, Xiao H. Expanding the eukaryotic genetic code with a biosynthesized 21st amino acid. Protein Sci 2022; 31:e4443. [PMID: 36173166 PMCID: PMC9601876 DOI: 10.1002/pro.4443] [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: 06/18/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 01/31/2023]
Abstract
Genetic code expansion technology allows for the use of noncanonical amino acids (ncAAs) to create semisynthetic organisms for both biochemical and biomedical applications. However, exogenous feeding of chemically synthesized ncAAs at high concentrations is required to compensate for the inefficient cellular uptake and incorporation of these components into proteins, especially in the case of eukaryotic cells and multicellular organisms. To generate organisms capable of autonomously biosynthesizing an ncAA and incorporating it into proteins, we have engineered a metabolic pathway for the synthesis of O-methyltyrosine (OMeY). Specifically, we endowed organisms with a marformycins biosynthetic pathway-derived methyltransferase that efficiently converts tyrosine to OMeY in the presence of the co-factor S-adenosylmethionine. The resulting cells can produce and site-specifically incorporate OMeY into proteins at much higher levels than cells exogenously fed OMeY. To understand the structural basis for the substrate selectivity of the transferase, we solved the X-ray crystal structures of the ligand-free and tyrosine-bound enzymes. Most importantly, we have extended this OMeY biosynthetic system to both mammalian cells and the zebrafish model to enhance the utility of genetic code expansion. The creation of autonomous eukaryotes using a 21st amino acid will make genetic code expansion technology more applicable to multicellular organisms, providing valuable vertebrate models for biological and biomedical research.
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Affiliation(s)
- Kuan‐Lin Wu
- Department of ChemistryRice UniversityHoustonTexasUSA
| | - Joshua A. Moore
- Department of BiosciencesRice UniversityHoustonTexasUSA
- Biochemistry and Cell Biology ProgramRice UniversityHoustonTexasUSA
| | | | - Yuda Chen
- Department of ChemistryRice UniversityHoustonTexasUSA
| | - Catherine Lee
- Department of ChemistryRice UniversityHoustonTexasUSA
| | - Weijun Xu
- Department of BiosciencesRice UniversityHoustonTexasUSA
| | - Zane Peng
- Department of ChemistryRice UniversityHoustonTexasUSA
| | - Qinghui Duan
- Department of ChemistryRice UniversityHoustonTexasUSA
| | - George N. Phillips
- Department of ChemistryRice UniversityHoustonTexasUSA
- Department of BiosciencesRice UniversityHoustonTexasUSA
| | - Rosa A. Uribe
- Department of BiosciencesRice UniversityHoustonTexasUSA
- Biochemistry and Cell Biology ProgramRice UniversityHoustonTexasUSA
| | - Han Xiao
- Department of ChemistryRice UniversityHoustonTexasUSA
- Department of BiosciencesRice UniversityHoustonTexasUSA
- Department of BioengineeringRice UniversityHoustonTexasUSA
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Sun Q, Gao S, Yu S, Zheng P, Zhou J. Production of (2S)-sakuranetin from (2S)-naringenin in Escherichia coli by strengthening methylation process and cell resistance. Synth Syst Biotechnol 2022; 7:1117-1125. [PMID: 36017331 PMCID: PMC9399173 DOI: 10.1016/j.synbio.2022.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/15/2022] Open
Abstract
(2S)-Sakuranetin is a 7-O-methylflavonoid that has anticancer, antiviral, and antimicrobial activities. Methylation process is involved in biosynthesizing (2S)-sakuranetin from (2S)-naringenin, in which S-adenosylmethionine (SAM) serves as the methyl donor. In this study, after methyl donor and substrate inhibition were identified as limiting factors for (2S)-sakuranetin biosynthesis, an efficient (2S)-sakuranetin-producing strain was constructed by enhancing methyl donor supply and cell tolerance to (2S)-naringenin. Firstly, PfOMT3 from Perilla frutescens was selected as the optimal flavonoid 7-O-methyltransferase (F7-OMT) for the conversion of (2S)-naringenin to (2S)-sakuranetin. Then, the methylation process was upregulated by regulating pyridoxal 5′-phosphate (PLP) content, key enzymes in methionine synthesis pathway, and the availability of ATP. Furthermore, genes that can enhance cell resistance to (2S)-naringenin were identified from molecular chaperones and sRNAs. Finally, by optimizing the fermentation process, 681.44 mg/L of (2S)-sakuranetin was obtained in 250-mL shake flasks. The titer of (2S)-sakuranetin reached 2642.38 mg/L in a 5-L bioreactor, which is the highest titer ever reported. This work demonstrates the importance of cofactor PLP in methylation process, and provides insights to biosynthesize other O-methylated flavonoids efficiently in E. coli.
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Affiliation(s)
- Qiumeng Sun
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Song Gao
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Shiqin Yu
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Pu Zheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Corresponding author. School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China.
| | - Jingwen Zhou
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, Wuxi, 214122, China
- Corresponding author. Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China.
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Tan Y, Yang J, Jiang Y, Sun S, Wei X, Wang R, Bu J, Li D, Kang L, Chen T, Guo J, Cui G, Tang J, Huang L. Identification and characterization of two Isatis indigotica O-methyltransferases methylating C-glycosylflavonoids. HORTICULTURE RESEARCH 2022; 9:uhac140. [PMID: 36072835 PMCID: PMC9437721 DOI: 10.1093/hr/uhac140] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Isatis indigotica accumulates several active substances, including C-glycosylflavonoids, which have important pharmacological activities and health benefits. However, enzymes catalyzing the methylation step of C-glycosylflavonoids in I. indigotica remain unknown. In this study, three O-methyltransferases (OMTs) were identified from I. indigotica that have the capacity for O-methylation of the C-glycosylflavonoid isoorientin. The Type II OMTs IiOMT1 and IiOMT2 efficiently catalyze isoorientin to form isoscoparin, and decorate one of the aromatic vicinal hydroxyl groups on flavones and methylate the C6, C8, and 3'-hydroxyl positions to form oroxylin A, wogonin, and chrysoeriol, respectively. However, the Type I OMT IiOMT3 exhibited broader substrate promiscuity and methylated the C7 and 3'-hydroxyl positions of flavonoids. Further site-directed mutagenesis studies demonstrated that five amino acids of IiOMT1/IiOMT2 (D121/D100, D173/D149, A174/A150R, N200/N176, and D248/D233) were critical residues for their catalytic activity. Additionally, only transient overexpression of Type II OMTs IiOMT1 and IiOMT2 in Nicotiana benthamiana significantly increased isoscoparin accumulation, indicating that the Type II OMTs IiOMT1 and IiOMT2 could catalyze the methylation step of C-glycosylflavonoid, isoorientin at the 3'-hydroxyl position. This study provides insights into the biosynthesis of methylated C-glycosylflavonoids, and IiOMTs could be promising catalysts in the synthesis of bioactive compounds.
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Affiliation(s)
- Yuping Tan
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
- School of Traditional Chinese Medicine, Shenyang Pharmaceutical University, Shenyang 117004, China
| | - Jian Yang
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yinyin Jiang
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Shufu Sun
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
- School of Pharmacy, Anhui University of Chinese Medicine, Hefei 230012, China
| | - Xiaoyan Wei
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
- College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun 130118, China
| | - Ruishan Wang
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Junling Bu
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Dayong Li
- National Engineering Research Center for Vegetables, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing 100097, China
| | - Liping Kang
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Tong Chen
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Juan Guo
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Guanghong Cui
- State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
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Liu J, Tian M, Wang Z, Xiao F, Huang X, Shan Y. Production of hesperetin from naringenin in an engineered Escherichia coli consortium. J Biotechnol 2022; 347:67-76. [DOI: 10.1016/j.jbiotec.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 11/17/2022]
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Comparative Transcriptome Analysis of the Accumulation of Anthocyanins Revealed the Underlying Metabolic and Molecular Mechanisms of Purple Pod Coloration in Okra ( Abelmoschus esculentus L.). Foods 2021; 10:foods10092180. [PMID: 34574288 PMCID: PMC8471371 DOI: 10.3390/foods10092180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/05/2021] [Accepted: 09/10/2021] [Indexed: 11/17/2022] Open
Abstract
Color is an essential agronomic trait and the consumption of high anthocyanin containing vegetables in daily diet does provide benefits to human health, but the mechanisms on anthocyanin accumulation in tender pods of okra (Abelmoschus esculentus L.) were totally unknown. In this study, a wide characterization and quantitation of anthocyanins and flavonols in tender pods of 15 okra varieties were performed by UHPLC-Q-Orbitrap HRMS for the first time. Two major anthocyanins (delphinidin 3-O-sambubioside and cyanidin 3-O-sambubioside) and six kinds of flavonol glycosides (most are quercetin-based) were identified and quantified. The coloration of the purple okra pod mainly arises from the accumulation of both delphinidin 3-O-sambubioside and cyanidin 3-O-sambubioside in most of purple varieties (Hong Yu, Bowling Red and Burgundy), except Jing Orange. The significant differences in the compositions and contents of anthocyanins are responsible for the pod color ranging from brick-red to purplish-red among the various okra cultivars. Furthermore, four representative okra cultivars exhibiting obvious differences in anthocyanin accumulation were further analyzed with transcriptome and more than 4000 conserved differentially expressed genes were identified across the three compared groups (B vs. BR, B vs. HY and B vs. JO). Based on the comprehensive analysis of transcriptomic data, it was indicated that MBW complex consisting of AeMYB114, AeTT8, and AeTTG1 and other transcriptional factors coordinately regulate the accumulation of anthocyanins via the transcriptional regulation of structural genes. Moreover, four independent working models explaining the diversities of anthocyanin pigmentation in okra pods were also proposed. Altogether, these results improved our understanding on anthocyanin accumulation in okra pods, and provided strong supports for the development of okra pod as a functional food in the future.
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Improvement of Cucurbitacin B Content in Cucumis melo Pedicel Extracts by Biotransformation Using Recombinant β-Glucosidase. SEPARATIONS 2021. [DOI: 10.3390/separations8090138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli BL21(DE3). The activity of recombinant β-glucosidase with p-nitrophenyl-β-d-glucoside (pNPG) as a substrate was 3.48 U/mL in a culture. Using the recombinant β-glucosidase for the biotransformation of C. melo pedicel extracts, CuBg was converted into CuB with a conversion rate of 87.6% when the concentration of CuBg was 0.973 g/L in a reaction mixtures. The concentration of CuB in C. melo pedicel extracts was improved from 13.6 to 20.2 g/L after biotransformation. The present study provides high-efficiency technology for the production of CuB from its glycoside by biotransformation.
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