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Lam LPY, Lui ACW, Bartley LE, Mikami B, Umezawa T, Lo C. Multifunctional 5-hydroxyconiferaldehyde O-methyltransferases (CAldOMTs) in plant metabolism. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1671-1695. [PMID: 38198655 DOI: 10.1093/jxb/erae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 01/09/2024] [Indexed: 01/12/2024]
Abstract
Lignin, flavonoids, melatonin, and stilbenes are plant specialized metabolites with diverse physiological and biological functions, supporting plant growth and conferring stress resistance. Their biosynthesis requires O-methylations catalyzed by 5-hydroxyconiferaldehyde O-methyltransferase (CAldOMT; also called caffeic acid O-methyltransferase, COMT). CAldOMT was first known for its roles in syringyl (S) lignin biosynthesis in angiosperm cell walls and later found to be multifunctional. This enzyme also catalyzes O-methylations in flavonoid, melatonin, and stilbene biosynthetic pathways. Phylogenetic analysis indicated the convergent evolution of enzymes with OMT activities towards the monolignol biosynthetic pathway intermediates in some gymnosperm species that lack S-lignin and Selaginella moellendorffii, a lycophyte which produces S-lignin. Furthermore, neofunctionalization of CAldOMTs occurred repeatedly during evolution, generating unique O-methyltransferases (OMTs) with novel catalytic activities and/or accepting novel substrates, including lignans, 1,2,3-trihydroxybenzene, and phenylpropenes. This review summarizes multiple aspects of CAldOMTs and their related proteins in plant metabolism and discusses their evolution, molecular mechanism, and roles in biorefineries, agriculture, and synthetic biology.
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Affiliation(s)
- Lydia Pui Ying Lam
- Graduate School of Engineering Science, Akita University, Tegata Gakuen-machi 1-1, Akita City, Akita 010-0852, Japan
| | - Andy C W Lui
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Laura E Bartley
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Bunzo Mikami
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Toshiaki Umezawa
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
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Daniel-Ivad P, Ryan KS. Structure of methyltransferase RedM that forms the dimethylpyrrolinium of the bisindole reductasporine. J Biol Chem 2024; 300:105520. [PMID: 38042494 PMCID: PMC10784701 DOI: 10.1016/j.jbc.2023.105520] [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: 08/08/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Bisindoles are biologically active natural products that arise from the oxidative dimerization of two molecules of l-tryptophan. In bacterial bisindole pathways, a core set of transformations is followed by the action of diverse tailoring enzymes that catalyze reactions that lead to diverse bisindole products. Among bisindoles, reductasporine is distinct due to its dimethylpyrrolinium structure. Its previously reported biosynthetic gene cluster encodes two unique tailoring enzymes, the imine reductase RedE and the dimethyltransferase RedM, which were shown to produce reductasporine from a common bisindole intermediate in recombinant E. coli. To gain more insight into the unique tailoring enzymes in reductasporine assembly, we reconstituted the biosynthetic pathway to reductasporine in vitro and then solved the 1.7 Å resolution structure of RedM. Our work reveals RedM adopts a variety of conformational changes with distinct open and closed conformations, and site-directed mutagenesis alongside sequence analysis identifies important active site residues. Finally, our work sets the stage for understanding how RedM evolved to react with a pyrrolinium scaffold and may enable the development of new dimethyltransferase catalysts.
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Affiliation(s)
- Phillip Daniel-Ivad
- Department of Chemistry, The University of British Columbia, Vancouver, Canada
| | - Katherine S Ryan
- Department of Chemistry, The University of British Columbia, Vancouver, Canada.
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3
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Lui ACW, Pow KC, Lin N, Lam LPY, Liu G, Godwin ID, Fan Z, Khoo CJ, Tobimatsu Y, Wang L, Hao Q, Lo C. Regioselective stilbene O-methylations in Saccharinae grasses. Nat Commun 2023; 14:3462. [PMID: 37308495 DOI: 10.1038/s41467-023-38908-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 05/18/2023] [Indexed: 06/14/2023] Open
Abstract
O-Methylated stilbenes are prominent nutraceuticals but rarely produced by crops. Here, the inherent ability of two Saccharinae grasses to produce regioselectively O-methylated stilbenes is reported. A stilbene O-methyltransferase, SbSOMT, is first shown to be indispensable for pathogen-inducible pterostilbene (3,5-bis-O-methylated) biosynthesis in sorghum (Sorghum bicolor). Phylogenetic analysis indicates the recruitment of genus-specific SOMTs from canonical caffeic acid O-methyltransferases (COMTs) after the divergence of Sorghum spp. from Saccharum spp. In recombinant enzyme assays, SbSOMT and COMTs regioselectively catalyze O-methylation of stilbene A-ring and B-ring respectively. Subsequently, SOMT-stilbene crystal structures are presented. Whilst SbSOMT shows global structural resemblance to SbCOMT, molecular characterizations illustrate two hydrophobic residues (Ile144/Phe337) crucial for substrate binding orientation leading to 3,5-bis-O-methylations in the A-ring. In contrast, the equivalent residues (Asn128/Asn323) in SbCOMT facilitate an opposite orientation that favors 3'-O-methylation in the B-ring. Consistently, a highly-conserved COMT is likely involved in isorhapontigenin (3'-O-methylated) formation in wounded wild sugarcane (Saccharum spontaneum). Altogether, our work reveals the potential of Saccharinae grasses as a source of O-methylated stilbenes, and rationalize the regioselectivity of SOMT activities for bioengineering of O-methylated stilbenes.
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Affiliation(s)
- Andy C W Lui
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Kah Chee Pow
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Nan Lin
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Lydia Pui Ying Lam
- Center for Crossover Education, Graduate School of Engineering Science, Akita University, Tegata Gakuen-machi 1-1, Akita City, Akita, 010-8502, Japan
| | - Guoquan Liu
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ian D Godwin
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhuming Fan
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Chen Jing Khoo
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yuki Tobimatsu
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Lanxiang Wang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Quan Hao
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
- China Spallation Neutron Source, Dongguan, Guangdong, 523000, China.
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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Yu Y, Liu Y, Dong G, Jiang J, Leng L, Liu X, Zhang J, Liu A, Chen S. Functional characterization and key residues engineering of a regiopromiscuity O-methyltransferase involved in benzylisoquinoline alkaloid biosynthesis in Nelumbo nucifera. HORTICULTURE RESEARCH 2023; 10:uhac276. [PMID: 36789257 PMCID: PMC9923211 DOI: 10.1093/hr/uhac276] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/09/2022] [Accepted: 12/02/2022] [Indexed: 06/18/2023]
Abstract
Lotus (Nelumbo nucifera), an ancient aquatic plant, possesses a unique pharmacological activity that is primarily contributed by benzylisoquinoline alkaloids (BIAs). However, only few genes and enzymes involved in BIA biosynthesis in N. nucifera have been isolated and characterized. In the present study we identified the regiopromiscuity of an O-methyltransferase, designated NnOMT6, isolated from N. nucifera; NnOMT6 was found to catalyze the methylation of monobenzylisoquinoline 6-O/7-O, aporphine skeleton 6-O, phenylpropanoid 3-O, and protoberberine 2-O. We further probed the key residues affecting NnOMT6 activity via molecular docking and molecular dynamics simulation. Verification using site-directed mutagenesis revealed that residues D316, N130, L135, N176A, D269, and E328 were critical for BIA O-methyltransferase activities; furthermore, N323A, a mutant of NnOMT6, demonstrated a substantial increase in catalytic efficiency for BIAs and a broader acceptor scope compared with wild-type NnOMT6. To the best of our knowledge, this is the first study to report the O-methyltransferase activity of an aporphine skeleton without benzyl moiety substitutions in N. nucifera. The study findings provide biocatalysts for the semisynthesis of related medical compounds and give insights into protein engineering to strengthen O-methyltransferase activity in plants.
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Affiliation(s)
- Yuetong Yu
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | - Yan Liu
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | | | - JinZhu Jiang
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | - Liang Leng
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | - XianJu Liu
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | - Jun Zhang
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, No. 16, Nanxiaojie, Dongzhimennei, Beijing 100700, China
| | - An Liu
- Corresponding author. E-mail: ;
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5
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Lashley A, Miller R, Provenzano S, Jarecki SA, Erba P, Salim V. Functional Diversification and Structural Origins of Plant Natural Product Methyltransferases. Molecules 2022; 28:molecules28010043. [PMID: 36615239 PMCID: PMC9822479 DOI: 10.3390/molecules28010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
In plants, methylation is a common step in specialized metabolic pathways, leading to a vast diversity of natural products. The methylation of these small molecules is catalyzed by S-adenosyl-l-methionine (SAM)-dependent methyltransferases, which are categorized based on the methyl-accepting atom (O, N, C, S, or Se). These methyltransferases are responsible for the transformation of metabolites involved in plant defense response, pigments, and cell signaling. Plant natural product methyltransferases are part of the Class I methyltransferase-superfamily containing the canonical Rossmann fold. Recent advances in genomics have accelerated the functional characterization of plant natural product methyltransferases, allowing for the determination of substrate specificities and regioselectivity and further realizing the potential for enzyme engineering. This review compiles known biochemically characterized plant natural product methyltransferases that have contributed to our knowledge in the diversification of small molecules mediated by methylation steps.
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Affiliation(s)
- Audrey Lashley
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
| | - Ryan Miller
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
- School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA 70112, USA
| | - Stephanie Provenzano
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
- School of Medicine, Louisiana State University Health Shreveport, Shreveport, LA 71103, USA
| | - Sara-Alexis Jarecki
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
| | - Paul Erba
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
- School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA 70112, USA
| | - Vonny Salim
- Department of Biological Sciences, Louisiana State University, Shreveport, LA 71115, USA
- Correspondence:
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Abdelraheem E, Thair B, Varela RF, Jockmann E, Popadić D, Hailes HC, Ward JM, Iribarren AM, Lewkowicz ES, Andexer JN, Hagedoorn PL, Hanefeld U. Methyltransferases, functions and applications. Chembiochem 2022; 23:e202200212. [PMID: 35691829 PMCID: PMC9539859 DOI: 10.1002/cbic.202200212] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/10/2022] [Indexed: 11/25/2022]
Abstract
In this review the current state‐of‐the‐art of S‐adenosylmethionine (SAM)‐dependent methyltransferases and SAM are evaluated. Their structural classification and diversity is introduced and key mechanistic aspects presented which are then detailed further. Then, catalytic SAM as a target for drugs, and approaches to utilise SAM as a cofactor in synthesis are introduced with different supply and regeneration approaches evaluated. The use of SAM analogues are also described. Finally O‐, N‐, C‐ and S‐MTs, their synthetic applications and potential for compound diversification is given.
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Affiliation(s)
| | - Benjamin Thair
- University College London Faculty of Mathematical and Physical Sciences, department of Chemistry, UNITED KINGDOM
| | - Romina Fernández Varela
- Universidad nacional di Quilmes, 3Laboratorio de Biotransformaciones y Química de Ácidos Nucleicos, ARGENTINA
| | - Emely Jockmann
- Albert-Ludwigs-Universitat Freiburg Universitatsbibliothek Freiburg, Pharmacie, GERMANY
| | | | - Helen C Hailes
- University College London Faculty of Mathematical and Physical Sciences, department of Chemistry, UNITED KINGDOM
| | - John M Ward
- University College London, Department of Biochemical Engineering, UNITED KINGDOM
| | - Adolfo M Iribarren
- Universidad Nacional de Quilmes, 3Laboratorio de Biotransformaciones y Química de Ácidos Nucleicos, ARGENTINA
| | - Elizabeth S Lewkowicz
- Universidad Nacional de Quilmes, Laboratorio de Biotransformaciones y Química de Ácidos Nucleicos, ARGENTINA
| | | | | | - Ulf Hanefeld
- Technische Universiteit Delft, Gebouw voor Scheikunde, Julianalaan 136, 2628 BL, Delft, NETHERLANDS
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7
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Xue Y, Liang Y, Zhang W, Geng C, Feng D, Huang X, Dong S, Zhang Y, Sun J, Qi F, Lu X. Characterization and Structural Analysis of Emodin- O-Methyltransferase from Aspergillus terreus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:5728-5737. [PMID: 35475366 DOI: 10.1021/acs.jafc.2c01281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
All O-methylated derivatives of emodin, including physcion, questin, and 1-O-methylemodin, show potential antifungal activities. Notably, emodin and questin are two pivotal intermediates of geodin biosynthesis in Aspergillus terreus. Although most of the geodin biosynthetic steps have been investigated, the key O-methyltransferase (OMT) responsible for the O-methylation of emodin to generate questin has remained unidentified. Herein, through phylogenetic tree analysis and in vitro biochemical assays, the long-sought class II emodin-O-methyltransferase GedA has been functionally characterized. Additionally, the catalytic mechanism and key residues at the catalytic site of GedA were elucidated by enzyme-substrate-methyl donor analogue ternary complex crystal structure determination and site-directed mutagenesis. As we demonstrate, GedA adopts a typical general acid/base (E446/H373)-mediated transmethylation mechanism. In particular, residue D374 is also crucial for efficient catalysis through blocking the formation of intramolecular hydrogen bonds in emodin. This study will facilitate future engineering of GedA for the production of physcion or other site-specific O-methylated anthraquinone derivatives with potential applications as biopesticides.
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Affiliation(s)
- Yingying Xue
- Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo & Rattan Science and Technology, Beijing 100102, China
| | - Yajing Liang
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Wei Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ce Geng
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Dandan Feng
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Xuenian Huang
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sheng Dong
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Yingfang Zhang
- Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo & Rattan Science and Technology, Beijing 100102, China
| | - Jia Sun
- Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo & Rattan Science and Technology, Beijing 100102, China
| | - Feifei Qi
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Xuefeng Lu
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Marine Biology and Biotechnology Laboratory, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266101, China
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Somaletha Chandran K, Humphries J, Goodger JQ, Woodrow IE. Molecular Characterisation of Flavanone O-methylation in Eucalyptus. Int J Mol Sci 2022; 23:ijms23063190. [PMID: 35328610 PMCID: PMC8954846 DOI: 10.3390/ijms23063190] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 11/17/2022] Open
Abstract
Flavonoids are ubiquitous polyphenolic compounds in plants, long recognised for their health-promoting properties in humans. Methylated flavonoids have received increasing attention due to the potential of methylation to enhance medicinal efficacy. Recently, Eucalyptus species with high levels of the O-methylated flavanone pinostrobin have been identified. Pinostrobin has potential commercial value due to its numerous pharmacological and functional food benefits. Little is known about the identity or mode of action of the enzymes involved in methylating flavanones. This study aimed to identify and characterise the methyltransferase(s) involved in the regiospecific methylation of pinostrobin in Eucalyptus and thereby add to our limited understanding of flavanone biosynthesis in plants. RNA-seq analysis of leaf tips enabled the isolation of a gene encoding a flavanone 7-O-methyltransferase (EnOMT1) in Eucalyptus. Biochemical characterisation of its in vitro activity revealed a range of substrates upon which EnOMT1 acts in a regiospecific manner. Comparison to a homologous sequence from a Eucalyptus species lacking O-methylated flavonoids identified critical catalytic amino acid residues within EnOMT1 responsible for its activity. This detailed molecular characterisation identified a methyltransferase responsible for chemical ornamentation of the core flavanone structure of pinocembrin and helps shed light on the mechanism of flavanone biosynthesis in Eucalyptus.
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Affiliation(s)
| | - John Humphries
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia; (K.S.C.); (J.H.)
| | - Jason Q.D. Goodger
- School of Ecosystem and Forest Sciences, The University of Melbourne, Parkville, VIC 3010, Australia;
- Correspondence:
| | - Ian E. Woodrow
- School of Ecosystem and Forest Sciences, The University of Melbourne, Parkville, VIC 3010, Australia;
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Acyltransferase AniI, a Tailoring Enzyme with Broad Substrate Tolerance for High-Level Production of Anisomycin. Appl Environ Microbiol 2021; 87:e0017221. [PMID: 33931417 DOI: 10.1128/aem.00172-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anisomycin (compound 1), a pyrrolidine antibiotic, exhibits diverse biological and pharmacologic activities. The biosynthetic gene cluster of compound 1 has been identified previously, and the multistep assembly of the core benzylpyrrolidine scaffold was characterized. However, enzymatic modifications, such as acylation, involved in compound 1 biosynthesis are unknown. In this study, the genetic manipulation of aniI proved that it encoded an indispensable acetyltransferase for compound 1 biosynthesis. Bioinformatics analysis suggested AniI as a member of maltose (MAT) and galactoside O-acetyltransferases (GAT) with C-terminal left-handed parallel beta-helix (LbH) subdomain, which were referred to as LbH-MAT-GAT sugar O-acetyltransferases. However, the biochemical assay identified that its target site was the hydroxyl group of the pyrrolidine ring. AniI was found to be tolerant of acyl donors with different chain lengths for the biosynthesis of compound 1 and derivatives 12 and 13 with butyryl and isovaleryl groups, respectively. Meanwhile, it showed comparable activity toward biosynthetic intermediates and synthesized analogues, suggesting promiscuity to the pyrrolidine ring structure of compound 1. These data may inspire new viable synthetic routes for the construction of more complex pyrrolidine ring scaffolds in compound 1. Finally, the overexpression of aniI under the control of strong promoters contributed to the higher productivities of compound 1 and its analogues. These findings reported here not only improve the understanding of anisomycin biosynthesis but also expand the substrate scope of O-acetyltransferase working on the pyrrolidine ring and pave the way for future metabolic engineering construction of high-yield strains. IMPORTANCE Acylation is an important tailoring reaction during natural product biosynthesis. Acylation could increase the structural diversity and affect the chemical stability, volatility, biological activity, and even the cellular localization of specialized compounds. Many acetyltransferases have been reported in natural product biosynthesis. The typical example of the LbH-MAT-GAT sugar O-acetyltransferase subfamily was reported to catalyze the coenzyme A (CoA)-dependent acetylation of the 6-hydroxyl group of sugars. However, no protein of this family has been characterized to acetylate a nonsugar secondary metabolic product. Here, AniI was found to catalyze the acylation of the hydroxyl group of the pyrrolidine ring and be tolerant of diverse acyl donors and acceptors, which made the biosynthesis more efficient and exclusive for biosynthesis of compound 1 and its derivatives. Moreover, the overexpression of aniI serves as a successful example of genetic manipulation of a modification gene for the high production of final products and might set the stage for future metabolic engineering.
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Kong L, Wang Q, Yang W, Shen J, Li Y, Zheng X, Wang L, Chu Y, Deng Z, Chooi YH, You D. Three Recently Diverging Duplicated Methyltransferases Exhibit Substrate-Dependent Regioselectivity Essential for Xantholipin Biosynthesis. ACS Chem Biol 2020; 15:2107-2115. [PMID: 32649177 DOI: 10.1021/acschembio.0c00296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Polycyclic xanthones are characterized by highly oxygenated, angular hexacyclic frameworks and exhibit diverse biological activities. Although many of them have been isolated and chemically synthesized, the detailed biosynthetic machinery awaits discovery. Recently, xanthone construction in the xantholipin (1) pathway was shown to involve cryptic demethoxylation. This suggested a rationale for the existence of three O-methyltransferase (OMT) genes in the gene cluster, although there are only two O-methyl groups in the structure of 1. Here, in vivo and in vitro analysis have been used to show that the three paralogous OMTs, XanM1-M3, introduce individual methyl groups at specific points in the biosynthetic pathway. Each OMT can to some extent take over the role of the other OMTs, although they exhibit highly substrate-dependent regiospecificity. In addition, phylogenetic analysis suggests their evolution from a common ancestor. Four putative ancestral proteins were constructed, and one of them performed all the functions of XanM1-M3, while the others possessed more limited catalytic functions. The results suggest that a promiscuous common ancestor may have been able to catalyze all three reactions prior to gene duplication and functional divergence. The characterization of XanM1-M3 expands the enzyme inventory for polycyclic xanthone biosynthesis and suggests novel directed evolution approaches to diversifying natural product pathways.
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Affiliation(s)
- Lingxin Kong
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Qing Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Weinan Yang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jufang Shen
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yan Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Xiaoqing Zheng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Lu Wang
- Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Yiwen Chu
- Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu 610052, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yit-Heng Chooi
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia 6009, Australia
| | - Delin You
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China
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11
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Valentic TR, Payne JT, Smolke CD. Structure-Guided Engineering of a Scoulerine 9-O-Methyltransferase Enables the Biosynthesis of Tetrahydropalmatrubine and Tetrahydropalmatine in Yeast. ACS Catal 2020. [DOI: 10.1021/acscatal.9b05417] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Timothy R. Valentic
- Department of Bioengineering, Stanford University, 443 Via Ortega, MC 4245, Stanford, California 94305, United States
| | - James T. Payne
- Department of Bioengineering, Stanford University, 443 Via Ortega, MC 4245, Stanford, California 94305, United States
| | - Christina D. Smolke
- Department of Bioengineering, Stanford University, 443 Via Ortega, MC 4245, Stanford, California 94305, United States
- Chan Zuckerberg Biohub, San Francisco, California 94158, United States
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12
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Li Y, Winzer T, He Z, Graham IA. Over 100 Million Years of Enzyme Evolution Underpinning the Production of Morphine in the Papaveraceae Family of Flowering Plants. PLANT COMMUNICATIONS 2020; 1:100029. [PMID: 32685922 PMCID: PMC7357826 DOI: 10.1016/j.xplc.2020.100029] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/06/2019] [Accepted: 02/03/2020] [Indexed: 05/06/2023]
Abstract
Phylogenomic analysis of whole genome sequences of five benzylisoquinoline alkaloid (BIA)-producing species from the Ranunculales and Proteales orders of flowering plants revealed the sequence and timing of evolutionary events leading to the diversification of these compounds. (S)-Reticuline is a pivotal intermediate in the synthesis of many BIAs and our analyses revealed parallel evolution between the two orders, which diverged ∼122 million years ago (MYA). Berberine is present in species across the entire Ranunculales, and we found co-evolution of genes essential for production of the protoberberine class. The benzophenanthridine class, which includes the antimicrobial compound sanguinarine, is specific to the Papaveraceae family of Ranunculales, and biosynthetic genes emerged after the split with the Ranunculaceae family ∼110 MYA but before the split of the three Papaveraceae species used in this study at ∼77 MYA. The phthalideisoquinoline noscapine and morphinan class of BIAs are exclusive to the opium poppy lineage. Ks estimation of paralogous pairs indicates that morphine biosynthesis evolved more recently than 18 MYA in the Papaver genus. In the preceding 100 million years gene duplication, neofunctionalization and recruitment of additional enzyme classes, combined with gene clustering, gene fusion, and gene amplification, resulted in emergence of medicinally valuable BIAs including morphine and noscapine.
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Affiliation(s)
- Yi Li
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, UK
| | - Thilo Winzer
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, UK
| | - Zhesi He
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, UK
| | - Ian A. Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, UK
- Corresponding author
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13
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Menéndez-Perdomo IM, Facchini PJ. Isolation and characterization of two O-methyltransferases involved in benzylisoquinoline alkaloid biosynthesis in sacred lotus ( Nelumbo nucifera). J Biol Chem 2020; 295:1598-1612. [PMID: 31914404 PMCID: PMC7008365 DOI: 10.1074/jbc.ra119.011547] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/28/2019] [Indexed: 12/15/2022] Open
Abstract
Benzylisoquinoline alkaloids (BIAs) are a major class of plant metabolites with many pharmacological benefits. Sacred lotus (Nelumbo nucifera) is an ancient aquatic plant of medicinal value because of antiviral and immunomodulatory activities linked to its constituent BIAs. Although more than 30 BIAs belonging to the 1-benzylisoquinoline, aporphine, and bisbenzylisoquinoline structural subclasses and displaying a predominant R-enantiomeric conformation have been isolated from N. nucifera, its BIA biosynthetic genes and enzymes remain unknown. Herein, we report the isolation and biochemical characterization of two O-methyltransferases (OMTs) involved in BIA biosynthesis in sacred lotus. Five homologous genes, designated NnOMT1-5 and encoding polypeptides sharing >40% amino acid sequence identity, were expressed in Escherichia coli Functional characterization of the purified recombinant proteins revealed that NnOMT1 is a regiospecific 1-benzylisoquinoline 6-O-methyltransferase (6OMT) accepting both R- and S-substrates, whereas NnOMT5 is mainly a 7-O-methyltransferase (7OMT), with relatively minor 6OMT activity and a strong stereospecific preference for S-enantiomers. Available aporphines were not accepted as substrates by either enzyme, suggesting that O-methylation precedes BIA formation from 1-benzylisoquinoline intermediates. Km values for NnOMT1 and NnOMT5 were 20 and 13 μm for (R,S)-norcoclaurine and (S)-N-methylcoclaurine, respectively, similar to those for OMTs from other BIA-producing plants. Organ-based correlations of alkaloid content, OMT activity in crude extracts, and OMT gene expression supported physiological roles for NnOMT1 and NnOMT5 in BIA metabolism, occurring primarily in young leaves and embryos of sacred lotus. In summary, our work identifies two OMTs involved in BIA metabolism in the medicinal plant N. nucifera.
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Affiliation(s)
| | - Peter J Facchini
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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14
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Morris JS, Yu L, Facchini PJ. A single residue determines substrate preference in benzylisoquinoline alkaloid N-methyltransferases. PHYTOCHEMISTRY 2020; 170:112193. [PMID: 31765874 DOI: 10.1016/j.phytochem.2019.112193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 06/10/2023]
Abstract
N-methylation is a recurring feature in the biosynthesis of many plant specialized metabolites, including alkaloids. A crucial step in the conserved central pathway that provides intermediates for the biosynthesis of benzylisoquinoline alkaloids (BIAs) involves conversion of the secondary amine (S)-coclaurine into the tertiary amine (S)-N-methylcoclaurine by coclaurine N-methyltransferase (CNMT). Subsequent enzymatic steps yield the core intermediate (S)-reticuline, from which various branch pathways for the biosynthesis of major BIAs such as morphine, noscapine and sanguinarine diverge. An additional N-methylation yielding quaternary BIAs is catalyzed by reticuline N-methyltransferase (RNMT), such as in the branch pathway leading to the taxonomically widespread and ecologically significant alkaloid magnoflorine. Despite their functional differences, analysis of primary sequence information has been unable to accurately distinguish between CNMT-like and RNMT-like enzymes, necessitating laborious in vitro screening. Furthermore, despite a recent emphasis on structural characterization of BIA NMTs, the features and mechanisms underlying the CNMT-RNMT functional dichotomy were unknown. We report the identification of structural variants tightly correlated with function in known BIA NMTs and show through reciprocal mutagenesis that a single residue acts as a switch between CNMT- and RNMT-like functions. We use yeast in vivo screening to show that this discovery allows for accurate prediction of activity strictly from primary sequence information and, on this basis, improve the annotation of previously reported putative BIA NMTs. Our results highlight the unusually short mutational distance separating ancestral CNMT-like enzymes from more evolutionarily advanced RNMT-like enzymes, and thus help explain the widespread yet sporadic occurrence of quaternary BIAs in plants. While this is the first report of structural variants controlling mono-versus di-methylation activity among plant NMT enzymes, comparison with bacterial MT enzymes also suggests possible convergent evolution.
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Affiliation(s)
- Jeremy S Morris
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada
| | - Lisa Yu
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada
| | - Peter J Facchini
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada.
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15
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Morris JS, Facchini PJ. Molecular Origins of Functional Diversity in Benzylisoquinoline Alkaloid Methyltransferases. FRONTIERS IN PLANT SCIENCE 2019; 10:1058. [PMID: 31543888 PMCID: PMC6730481 DOI: 10.3389/fpls.2019.01058] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/30/2019] [Indexed: 05/25/2023]
Abstract
O- and N-methylations are ubiquitous and recurring features in the biosynthesis of many specialized metabolites. Accordingly, the methyltransferase (MT) enzymes catalyzing these modifications are directly responsible for a substantial fraction of the vast chemodiversity observed in plants. Enabled by DNA sequencing and synthesizing technologies, recent studies have revealed and experimentally validated the trajectories of molecular evolution through which MTs, such as those biosynthesizing caffeine, emerge and shape plant chemistry. Despite these advances, the evolutionary origins of many other alkaloid MTs are still unclear. Focusing on benzylisoquinoline alkaloid (BIA)-producing plants such as opium poppy, we review the functional breadth of BIA N- and O-MT enzymes and their relationship with the chemical diversity of their host species. Drawing on recent structural studies, we discuss newfound insight regarding the molecular determinants of BIA MT function and highlight key hypotheses to be tested. We explore what is known and suspected concerning the evolutionary histories of BIA MTs and show that substantial advances in this domain are within reach. This new knowledge is expected to greatly enhance our conceptual understanding of the evolutionary origins of specialized metabolism.
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