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Feng KN, Zhang Y, Zhang M, Yang YL, Liu JK, Pan L, Zeng Y. A flavin-monooxygenase catalyzing oxepinone formation and the complete biosynthesis of vibralactone. Nat Commun 2023; 14:3436. [PMID: 37301868 PMCID: PMC10257657 DOI: 10.1038/s41467-023-39108-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Oxepinone rings represent one of structurally unusual motifs of natural products and the biosynthesis of oxepinones is not fully understood. 1,5-Seco-vibralactone (3) features an oxepinone motif and is a stable metabolite isolated from mycelial cultures of the mushroom Boreostereum vibrans. Cyclization of 3 forms vibralactone (1) whose β-lactone-fused bicyclic core originates from 4-hydroxybenzoate, yet it remains elusive how 4-hydroxybenzoate is converted to 3 especially for the oxepinone ring construction in the biosynthesis of 1. In this work, using activity-guided fractionation together with proteomic analyses, we identify an NADPH/FAD-dependent monooxygenase VibO as the key enzyme performing a crucial ring-expansive oxygenation on the phenol ring to generate the oxepin-2-one structure of 3. The crystal structure of VibO reveals that it forms a dimeric phenol hydroxylase-like architecture featured with a unique substrate-binding pocket adjacent to the bound FAD. Computational modeling and solution studies provide insight into the likely VibO active site geometry, and suggest possible involvement of a flavin-C4a-OO(H) intermediate.
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Affiliation(s)
- Ke-Na Feng
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yue Zhang
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Mingfang Zhang
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yan-Long Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China
| | - Ji-Kai Liu
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Lifeng Pan
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Ying Zeng
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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2
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Yang C, Zhang L, Zhang W, Huang C, Zhu Y, Jiang X, Liu W, Zhao M, De BC, Zhang C. Biochemical and structural insights of multifunctional flavin-dependent monooxygenase FlsO1-catalyzed unexpected xanthone formation. Nat Commun 2022; 13:5386. [PMID: 36104338 PMCID: PMC9474520 DOI: 10.1038/s41467-022-33131-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 09/02/2022] [Indexed: 11/18/2022] Open
Abstract
Xanthone-containing natural products display diverse pharmacological properties. The biosynthetic mechanisms of the xanthone formation have not been well documented. Here we show that the flavoprotein monooxygenase FlsO1 in the biosynthesis of fluostatins not only functionally compensates for the monooxygenase FlsO2 in converting prejadomycin to dehydrorabelomycin, but also unexpectedly converts prejadomycin to xanthone-containing products by catalyzing three successive oxidations including hydroxylation, epoxidation and Baeyer-Villiger oxidation. We also provide biochemical evidence to support the physiological role of FlsO1 as the benzo[b]-fluorene C5-hydrolase by using nenestatin C as a substrate mimic. Finally, we resolve the crystal structure of FlsO1 in complex with the cofactor flavin adenine dinucleotide close to the “in” conformation to enable the construction of reactive substrate-docking models to understand the basis of a single enzyme-catalyzed multiple oxidations. This study highlights a mechanistic perspective for the enzymatic xanthone formation in actinomycetes and sets an example for the versatile functions of flavoproteins. The biosynthesis of xanthones has not been well documented. Here, the authors report that monooxygenase FlsO1 catalyzes three successive oxidations – hydroxylation, epoxidation and Baeyer–Villiger oxidation—to form the xanthone scaffold in actinomycetes.
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3
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An C, Zhu F, Yao Y, Zhang K, Wang W, Zhang J, Wei G, Xia Y, Gao Q, Gao SS. Beyond the cyclopropyl ring formation: fungal Aj_EasH catalyzes asymmetric hydroxylation of ergot alkaloids. Appl Microbiol Biotechnol 2022; 106:2981-2991. [PMID: 35389067 DOI: 10.1007/s00253-022-11892-4] [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: 11/02/2021] [Revised: 03/12/2022] [Accepted: 03/19/2022] [Indexed: 11/28/2022]
Abstract
Ergot alkaloids (EAs) are among the most important bioactive natural products. FeII/α-ketoglutarate-dependent dioxygenase Aj_EasH from Aspergillus japonicus is responsible for the formation of the cyclopropyl ring of the ergot alkaloid (EA) cycloclavine (4). Herein we reconstituted the biosynthesis of 4 in vitro from prechanoclavine (1) for the first time. Additionally, an unexpected activity of asymmetric hydroxylation at the C-4 position of EA compound festuclavine (5) for Aj_EasH was revealed. Furthermore, Aj_EasH also catalyzes the hydroxylation of two more EAs 9,10-dihydrolysergol (6) and elymoclavine (7). Thus, our results proved that Aj_EasH is a promiscuous and bimodal dioxygenase that catalyzes both the formation of cyclopropyl ring in 4 and the asymmetric hydroxylation of EAs. Molecular docking (MD) revealed the substrate-binding mode as well as the catalytic mechanism of asymmetric hydroxylation, suggesting more EAs could potentially be recognized and hydroxylated by Aj_EasH. Overall, the newly discovered activity empowered Aj_EasH with great potential for producing more diverse and bioactive EA derivatives. KEY POINTS: • Aj_EasH was revealed to be a promiscuous and bimodal FeII/α-ketoglutarate-dependent dioxygenase. • Aj_EasH converted festuclavine, 9,10-dihydrolysergol, and elymoclavine to their hydroxylated derivatives. • The catalytic mechanism of Aj_EasH for hydroxylation was analyzed by molecular docking.
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Affiliation(s)
- Chunyan An
- Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education, Biotechnology College of Tianjin University of Science and Technology, Tianjin, 300457, China. .,State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
| | - Fangfang Zhu
- Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education, Biotechnology College of Tianjin University of Science and Technology, Tianjin, 300457, China.,State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yongpeng Yao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Kexin Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Wei Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Jun Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Guangzheng Wei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Yue Xia
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Qiang Gao
- Key Laboratory of Industrial Fermentation Microbiology of Ministry of Education, Biotechnology College of Tianjin University of Science and Technology, Tianjin, 300457, China.
| | - Shu-Shan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
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4
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Shu X, Wei G, Qiao Y, Zhang K, Zhang J, Ai G, Tang MC, Zhang Y, Gao SS. TerC Is a Multifunctional and Promiscuous Flavoprotein Monooxygenase That Catalyzes Bimodal Oxidative Transformations. Org Lett 2021; 23:8947-8951. [PMID: 34743520 DOI: 10.1021/acs.orglett.1c03432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The flavoprotein monooxygenase (FPMO) TerC is encoded by all known cyclopentene biosynthetic gene clusters. It can catalyze oxidative dearomatization toward a series of 6-HM analogues and further induces different skeletal distortions to form either benzoquinone or pyrone by bimodal reaction cascades, which is only governed by the C7 substitutions. Beyond our study demonstrated bimodal reaction cascades and advanced the biosynthetic knowledge of fungal cyclopentenes, this work also sets the stage for the bioengineering of 6-HM polyketides.
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Affiliation(s)
- Xian Shu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Guangzheng Wei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Yuben Qiao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Kexin Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Jun Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guomin Ai
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Man-Cheng Tang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yonghui Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shu-Shan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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5
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Liu SH, Wei YY, Xing YN, Chen Y, Wang W, Wang KB, Liang Y, Jiao RH, Zhang B, Ge HM. A BBE-like Oxidase, AsmF, Dictates the Formation of Naphthalenic Hydroxyl Groups in Ansaseomycin Biosynthesis. Org Lett 2021; 23:3724-3728. [PMID: 33877854 DOI: 10.1021/acs.orglett.1c01101] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ansaseomycins are ansamycin-type natural products produced through expression of the asm gene cluster in a heterologous host. A rare berberine bridge enzyme (BBE) like oxidase, AsmF, is encoded in the asm gene cluster. Deletion of asmF led to the accumulation of a series of structurally diverse compounds, all of which lacked the 23-hydroxyl group in naphthalenic motif. Our work demonstrated that AsmF dictated the formation of the naphthalenic hydroxyl group in ansaseomycin biosynthesis.
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Affiliation(s)
- Shuang He Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yuan Yuan Wei
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yin Nan Xing
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yu Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wen Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Kai Biao Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Rui Hua Jiao
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Bo Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Hui Ming Ge
- State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Chemistry and Biomedicine Innovation Center, School of Life Sciences, Nanjing University, Nanjing 210023, China
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