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Yancey CE, Hart L, Hefferan S, Mohamed OG, Newmister SA, Tripathi A, Sherman DH, Dick GJ. Metabologenomics reveals strain-level genetic and chemical diversity of Microcystis secondary metabolism. mSystems 2024; 9:e0033424. [PMID: 38916306 PMCID: PMC11264947 DOI: 10.1128/msystems.00334-24] [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: 03/08/2024] [Accepted: 04/22/2024] [Indexed: 06/26/2024] Open
Abstract
Microcystis spp. are renowned for producing the hepatotoxin microcystin in freshwater cyanobacterial harmful algal blooms around the world, threatening drinking water supplies and public and environmental health. However, Microcystis genomes also harbor numerous biosynthetic gene clusters (BGCs) encoding the biosynthesis of other secondary metabolites, including many with toxic properties. Most of these BGCs are uncharacterized and currently lack links to biosynthesis products. However, recent field studies show that many of these BGCs are abundant and transcriptionally active in natural communities, suggesting potentially important yet unknown roles in bloom ecology and water quality. Here, we analyzed 21 xenic Microcystis cultures isolated from western Lake Erie to investigate the diversity of the biosynthetic potential of this genus. Through metabologenomic and in silico approaches, we show that these Microcystis strains contain variable BGCs, previously observed in natural populations, and encode distinct metabolomes across cultures. Additionally, we find that the majority of metabolites and gene clusters are uncharacterized, highlighting our limited understanding of the chemical repertoire of Microcystis spp. Due to the complex metabolomes observed in culture, which contain a wealth of diverse congeners as well as unknown metabolites, these results underscore the need to deeply explore and identify secondary metabolites produced by Microcystis beyond microcystins to assess their impacts on human and environmental health.IMPORTANCEThe genus Microcystis forms dense cyanobacterial harmful algal blooms (cyanoHABs) and can produce the toxin microcystin, which has been responsible for drinking water crises around the world. While microcystins are of great concern, Microcystis also produces an abundance of other secondary metabolites that may be of interest due to their potential for toxicity, ecological importance, or pharmaceutical applications. In this study, we combine genomic and metabolomic approaches to study the genes responsible for the biosynthesis of secondary metabolites as well as the chemical diversity of produced metabolites in Microcystis strains from the Western Lake Erie Culture Collection. This unique collection comprises Microcystis strains that were directly isolated from western Lake Erie, which experiences substantial cyanoHAB events annually and has had negative impacts on drinking water, tourism, and industry.
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Affiliation(s)
- Colleen E. Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Lauren Hart
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Sierra Hefferan
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology, and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Osama G. Mohamed
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Sean A. Newmister
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology, and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Gregory J. Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research (CIGLR), School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
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2
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Campos TGV, Gama WA, Geraldes V, Yoon J, Crnkovic CM, Pinto E, Jacinavicius FR. New records on toxic cyanobacteria from Brazil: Exploring their occurrence and geography. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172689. [PMID: 38692315 DOI: 10.1016/j.scitotenv.2024.172689] [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: 09/06/2023] [Revised: 04/12/2024] [Accepted: 04/20/2024] [Indexed: 05/03/2024]
Abstract
Cyanobacterial Harmful Algal Blooms (CyanoHABs) pose a significant threat to communities globally, impacting ecosystems and public health. This study provides an in-depth review of the current state of cyanotoxins and the distribution of CyanoHABs species in Brazil, while also detailing the methods used for their detection. Four hundred and twenty-one incidents were analyzed from 1993 to 2021, compiling cyanotoxin records and toxic CyanoHABs occurrences. The investigation begins with the first detection of microcystins in 1994 and highlights pivotal moments, like the 1996 "Caruaru Syndrome" outbreak. This event encouraged research and updated cyanotoxin-monitoring guidelines. The Brazilian drought period of 2015-2016 exacerbated cyanobacterial growth and saxitoxin levels, coinciding with Zika-related microcephaly. This study delves into methods used for cyanotoxin analysis, including ELISA, bioassays, HPLC, and LC-MS. Additionally, we investigated the toxicity of 37 cyanobacterial strains isolated from various Brazilian environments. Extracts were tested against Artemia salina and analyzed by LC-MS. Results revealed toxicity in extracts from 49 % of cyanobacterial strains. LC-MS results were analyzed using GNPS MS/MS molecular networking for comparing experimental spectra with those of cyanotoxin standards against in-house databases and the existing literature. Our research underscores the variability in cyanotoxin production among species and over time, extending beyond microcystins. LC-MS results, interpreted through the GNPS platform, revealed six cyanotoxin groups in Brazilian strains. Yet, compounds present in 75 % of the toxic extracts remained unidentified. Further research is crucial for fully comprehending the impact of potentially harmful organisms on water quality and public health management strategies. The study highlights the urgent need for continuously monitoring cyanobacteria and the cyanotoxin inclusion of management in public health policies.
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Affiliation(s)
- Thaíssa Giovanna Valverde Campos
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil
| | - Watson A Gama
- Federal Rural University of Pernambuco, Rua Dom Manuel de Medeiros, s/n, Dois Irmãos, CEP 52171-900, Recife, PE, Brazil
| | - Vanessa Geraldes
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil; Centre for Nuclear Energy in Agriculture, University of São Paulo, CEP 13418-260, Piracicaba, SP, Brazil
| | - Jaewon Yoon
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil
| | - Camila M Crnkovic
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil
| | - Ernani Pinto
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil; Centre for Nuclear Energy in Agriculture, University of São Paulo, CEP 13418-260, Piracicaba, SP, Brazil
| | - Fernanda Rios Jacinavicius
- University of São Paulo, School of Pharmaceutical Sciences, Avenida Prof. Lineu Prestes, 580, Butantã, CEP 05508-900 São Paulo, SP, Brazil; Centre for Nuclear Energy in Agriculture, University of São Paulo, CEP 13418-260, Piracicaba, SP, Brazil.
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3
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Crooke AM, Chand AK, Cui Z, Balskus EP. Elucidation of Chalkophomycin Biosynthesis Reveals N-Hydroxypyrrole-Forming Enzymes. J Am Chem Soc 2024; 146:16268-16280. [PMID: 38810110 PMCID: PMC11177257 DOI: 10.1021/jacs.4c04712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/31/2024]
Abstract
Reactive functional groups, such as N-nitrosamines, impart unique bioactivities to the natural products in which they are found. Recent work has illuminated enzymatic N-nitrosation reactions in microbial natural product biosynthesis, motivating interest in discovering additional metabolites constructed using such reactivity. Here, we use a genome mining approach to identify over 400 cryptic biosynthetic gene clusters (BGCs) encoding homologues of the N-nitrosating biosynthetic enzyme SznF, including the BGC for chalkophomycin, a CuII-binding metabolite that contains a C-type diazeniumdiolate and N-hydroxypyrrole. Characterizing chalkophomycin biosynthetic enzymes reveals previously unknown enzymes responsible for N-hydroxypyrrole biosynthesis, including the first prolyl-N-hydroxylase, and a key step in the assembly of the diazeniumdiolate-containing amino acid graminine. Discovery of this pathway enriches our understanding of the biosynthetic logic employed in constructing unusual heteroatom-heteroatom bond-containing functional groups, enabling future efforts in natural product discovery and biocatalysis.
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Affiliation(s)
- Anne Marie Crooke
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Anika K. Chand
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Zheng Cui
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Emily P. Balskus
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
- Howard
Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, United States
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4
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Crooke AM, Chand AK, Cui Z, Balskus EP. Elucidation of chalkophomycin biosynthesis reveals N-hydroxypyrrole-forming enzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.24.577118. [PMID: 38328124 PMCID: PMC10849742 DOI: 10.1101/2024.01.24.577118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Reactive functional groups, such as N-nitrosamines, impart unique bioactivities to the natural products in which they are found. Recent work has illuminated enzymatic N-nitrosation reactions in microbial natural product biosynthesis, motivating an interest in discovering additional metabolites constructed using such reactivity. Here, we use a genome mining approach to identify over 400 cryptic biosynthetic gene clusters (BGCs) encoding homologs of the N-nitrosating biosynthetic enzyme SznF, including the BGC for chalkophomycin, a CuII-binding metabolite that contains a C-type diazeniumdiolate and N-hydroxypyrrole. Characterizing chalkophomycin biosynthetic enzymes reveals previously unknown enzymes responsible for N-hydroxypyrrole biosynthesis, including the first prolyl-N-hydroxylase, and a key step in assembly of the diazeniumdiolate-containing amino acid graminine. Discovery of this pathway enriches our understanding of the biosynthetic logic employed in constructing unusual heteroatom-heteroatom bond-containing functional groups, enabling future efforts in natural product discovery and biocatalysis.
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Affiliation(s)
- Anne Marie Crooke
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anika K. Chand
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Zheng Cui
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
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5
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Baunach M, Guljamow A, Miguel-Gordo M, Dittmann E. Harnessing the potential: advances in cyanobacterial natural product research and biotechnology. Nat Prod Rep 2024; 41:347-369. [PMID: 38088806 DOI: 10.1039/d3np00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Covering: 2000 to 2023Cyanobacteria produce a variety of bioactive natural products that can pose a threat to humans and animals as environmental toxins, but also have potential for or inspire pharmaceutical use. As oxygenic phototrophs, cyanobacteria furthermore hold great promise for sustainable biotechnology. Yet, the necessary tools for exploiting their biotechnological potential have so far been established only for a few model strains of cyanobacteria, while large untapped biosynthetic resources are hidden in slow-growing cyanobacterial genera that are difficult to access by genetic techniques. In recent years, several approaches have been developed to circumvent the bottlenecks in cyanobacterial natural product research. Here, we summarize current progress that has been made in unlocking or characterizing cryptic metabolic pathways using integrated omics techniques, orphan gene cluster activation, use of genetic approaches in original producers, heterologous expression and chemo-enzymatic techniques. We are mainly highlighting genomic mining concepts and strategies towards high-titer production of cyanobacterial natural products from the last 10 years and discuss the need for further research developments in this field.
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Affiliation(s)
- Martin Baunach
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
- University of Bonn, Institute of Pharmaceutical Biology, Nußallee 6, 53115 Bonn, Germany
| | - Arthur Guljamow
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
| | - María Miguel-Gordo
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
| | - Elke Dittmann
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
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6
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Woodhouse JN, Burford MA, Neilan BA, Jex A, Tichkule S, Sivonen K, Fewer DP, Grossart HP, Willis A. Long-term stability of the genome structure of the cyanobacterium, Dolichospermum in a deep German lake. HARMFUL ALGAE 2024; 133:102600. [PMID: 38485438 DOI: 10.1016/j.hal.2024.102600] [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: 11/11/2022] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 03/19/2024]
Abstract
Dolichospermum is a cyanobacterial genus commonly associated with toxic blooms in lakes and brackish water bodies worldwide, and is a long-term resident of Lake Stechlin, northeastern Germany. In recent decades, shifts in the phosphorus loading and phytoplankton species composition have seen increased biomass of Dolichospermum during summer blooms from 1998, peaking around 2005, and declining after 2020. Cyanobacteria are known to rapidly adapt to new environments, facilitated by genome adaptation. To investigate the changes in genomic features that may have occurred in Lake Stechlin Dolichospermum during this time of increased phosphorus loading and higher biomass, whole genome sequence analysis was performed on samples of ten akinetes isolated from ten, 1 cm segments of a sediment core, representing a ∼45-year period from 1970 to 2017. Comparison of these genomes with genomes of extant isolates revealed a clade of Dolichospermum that clustered with the ADA-6 genus complex, with remarkable genome stability, without gene gain or loss events in response to recent environmental changes. The genome characteristics indicate that this species is suited to a deep-chlorophyll maximum, including additional light-harvesting and phosphorus scavenging genes. Population SNP analysis revealed two sub-populations that shifted in dominance as the lake transitioned between oligotrophic and eutrophic conditions. Overall, the results show little change within the population, despite diversity between extant populations from different geographic locations and the in-lake changes in phosphorus concentrations.
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Affiliation(s)
- J N Woodhouse
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany
| | - M A Burford
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Brisbane, Australia
| | - B A Neilan
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan 2308, NSW, Australia
| | - A Jex
- Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | - S Tichkule
- Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - K Sivonen
- Department of Microbiology, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland
| | - D P Fewer
- Department of Microbiology, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland
| | - H-P Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775 Stechlin, Germany; Department of Biochemistry and Biology, Potsdam University, 14469 Potsdam, Germany
| | - A Willis
- Australian Rivers Institute, and School of Environment and Science, Griffith University, Brisbane, Australia.
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Fernandes KA, Fadul JC, Fiore MF, Pinto E. A systematic review on guanitoxin: General characteristics and ecological risks. CHEMOSPHERE 2024; 352:141277. [PMID: 38307340 DOI: 10.1016/j.chemosphere.2024.141277] [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: 05/30/2023] [Revised: 11/17/2023] [Accepted: 01/20/2024] [Indexed: 02/04/2024]
Abstract
Guanitoxin (GNT) is a potent cyanotoxin, with a relatively low number of publications (n = 51) compared to other cyanotoxins. Among the published studies, 35 % were on the effect of the toxin in animals, mainly in rodents and in vitro testing, followed by studies that identified species of cyanobacteria that produce GNT in aquatic systems and consequently accidental poisoning in wild and domestic animals (27 %). Studies that developed or tested methods for identifying the molecule, based on colorimetric and analytical techniques, represented 14 %, while 8 % were on GNT biosynthesis. Review articles and chemical isolation (6 %) and on the stability of the molecule (4 %) were the topics with the lowest number of publications. The results show the occurrence of GNT was identified mainly in eutrophic environments with a higher incidence in the American continent. Chemical characteristics of the molecule, such as short half-life in the environment, instability in solutions with alkaline pH values, temperature >23 °C, added to the lack of an analytical standard, are factors that make it difficult to identify and quantify it. However, GNT monitoring can be performed using LC-MS-MRM methods or genes specific to the newly discovered molecule.
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Affiliation(s)
- Kelly Afonsina Fernandes
- Center for Nuclear Energy in Agriculture, University of São Paulo. Piracicaba, São Paulo, Brazil.
| | - Jéssica Chaves Fadul
- Center for Nuclear Energy in Agriculture, University of São Paulo. Piracicaba, São Paulo, Brazil
| | - Marli Fátima Fiore
- Center for Nuclear Energy in Agriculture, University of São Paulo. Piracicaba, São Paulo, Brazil
| | - Ernani Pinto
- Center for Nuclear Energy in Agriculture, University of São Paulo. Piracicaba, São Paulo, Brazil
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8
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Liao Y, Wang XJ, Ma GL, Candra H, Qiu En SL, Khandelwal S, Liang ZX. Biosynthesis of Octacosamicin A: Uncommon Starter/extender Units and Product Releasing via Intermolecular Amidation. Chembiochem 2024; 25:e202300590. [PMID: 37908177 DOI: 10.1002/cbic.202300590] [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: 08/22/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 11/02/2023]
Abstract
Octacosamicin A is an antifungal metabolite featuring a linear polyene-polyol chain flanked by N-hydroxyguanidine and glycine moieties. We report here that sub-inhibitory concentrations of streptomycin elicited the production of octacosamicin A in Amycolatopsis azurea DSM 43854T . We identified the biosynthetic gene cluster (oca BGC) that encodes a modular polyketide synthase (PKS) system for assembling the polyene-polyol chain of octacosamicin A. Our analysis suggested that the N-hydroxyguanidine unit originates from a 4-guanidinobutyryl-CoA starter unit, while the PKS incorporates an α-hydroxyketone moiety using a (2R)-hydroxymalonyl-CoA extender unit. The modular PKS system contains a non-canonical terminal module that lacks thioesterase (TE) and acyl carrier protein (ACP) domains, indicating the biosynthesis is likely to employ an unconventional and cryptic off-loading mechanism that attaches glycine to the polyene-polyol chain via an intermolecular amidation reaction.
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Affiliation(s)
- Yanghui Liao
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
| | - Xue-Jiao Wang
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
| | - Guang-Lei Ma
- Future Health Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing, 314102, China
| | - Hartono Candra
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
| | - Sean Lee Qiu En
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
| | - Srashti Khandelwal
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, 67551, Singapore
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9
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Metcalf JS, Banack SA, Cox PA. Cyanotoxin Analysis of Air Samples from the Great Salt Lake. Toxins (Basel) 2023; 15:659. [PMID: 37999522 PMCID: PMC10675144 DOI: 10.3390/toxins15110659] [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: 09/27/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
The Great Salt Lake in Utah is the largest saline lake in the Western hemisphere and one of the largest terminal lakes in the world. Situated at the eastern edge of the Great Basin, it is a remnant of the freshwater Lake Bonneville whose water level precipitously lowered about 12,000 years ago due to a natural break in Red Rock pass to the north. It contains a diverse assemblage of cyanobacteria which vary spatially dependent on salinity. In 1984, the waters of the Great Salt Lake occupied 8500 km2. Nearly four decades later, the waters occupy 2500 km2-a reduction in surface area of 71%. With predominantly westerly winds, there is a potential for the adjacent metropolitan residents to the east to be exposed to airborne cyanobacteria- and cyanotoxin-containing dust. During the summer and fall months of 2022, air and dried sediment samples were collected and assessed for the presence of BMAA which has been identified as a risk factor for ALS. Collection of air samples equivalent to a person breathing for 1 h resulted in BMAA and isomers being found in some air samples, along with their presence in exposed lakebed samples. There was no clear relationship between the presence of these toxins in airborne and adjacent lakebed samples, suggesting that airborne toxins may originate from diffuse rather than point sources. These findings confirm that continued low water levels in the Great Salt Lake may constitute an increasing health hazard for the 2.5 million inhabitants of communities along the Wasatch Front.
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Affiliation(s)
- James S. Metcalf
- Brain Chemistry Labs, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
| | | | - Paul Alan Cox
- Brain Chemistry Labs, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
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Metcalf JS, Banack SA, Wyatt PB, Nunn PB, Cox PA. A Direct Analysis of β- N-methylamino-l-alanine Enantiomers and Isomers and Its Application to Cyanobacteria and Marine Mollusks. Toxins (Basel) 2023; 15:639. [PMID: 37999501 PMCID: PMC10674937 DOI: 10.3390/toxins15110639] [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: 08/17/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 11/25/2023] Open
Abstract
Of the wide variety of toxic compounds produced by cyanobacteria, the neurotoxic amino acid β-N-methylamino-l-alanine (BMAA) has attracted attention as a result of its association with chronic human neurodegenerative diseases such as ALS and Alzheimer's. Consequently, specific detection methods are required to assess the presence of BMAA and its isomers in environmental and clinical materials, including cyanobacteria and mollusks. Although the separation of isomers such as β-amino-N-methylalanine (BAMA), N-(2-aminoethyl)glycine (AEG) and 2,4-diaminobutyric acid (DAB) from BMAA has been demonstrated during routine analysis, a further compounding factor is the potential presence of enantiomers for some of these isomers. Current analytical methods for BMAA mostly do not discriminate between enantiomers, and the chiral configuration of BMAA in cyanobacteria is still largely unexplored. To understand the potential for the occurrence of D-BMAA in cyanobacteria, a chiral UPLC-MS/MS method was developed to separate BMAA enantiomers and isomers and to determine the enantiomeric configuration of endogenous free BMAA in a marine Lyngbya mat and two mussel reference materials. After extraction, purification and derivatization with N-(4-nitrophenoxycarbonyl)-l-phenylalanine 2-methoxyethyl ester ((S)-NIFE), both L- and D-BMAA were identified as free amino acids in cyanobacterial materials, whereas only L-BMAA was identified in mussel tissues. The finding of D-BMAA in biological environmental materials raises questions concerning the source and role of BMAA enantiomers in neurological disease.
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Affiliation(s)
- James S. Metcalf
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| | - Peter B. Wyatt
- The School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (P.B.W.); (P.B.N.)
| | - Peter B. Nunn
- The School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (P.B.W.); (P.B.N.)
| | - Paul A. Cox
- Brain Chemistry Labs, Box 3464, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
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11
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Li Z, Zhu X, Wu Z, Sun T, Tong Y. Recent Advances in Cyanotoxin Synthesis and Applications: A Comprehensive Review. Microorganisms 2023; 11:2636. [PMID: 38004647 PMCID: PMC10673588 DOI: 10.3390/microorganisms11112636] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
Over the past few decades, nearly 300 known cyanotoxins and more than 2000 cyanobacterial secondary metabolites have been reported from the environment. Traditional studies have focused on the toxic cyanotoxins produced by harmful cyanobacteria, which pose a risk to both human beings and wildlife, causing acute and chronic poisoning, resulting in diarrhea, nerve paralysis, and proliferation of cancer cells. Actually, the biotechnological potential of cyanotoxins is underestimated, as increasing studies have demonstrated their roles as valuable products, including allelopathic agents, insecticides and biomedicines. To promote a comprehensive understanding of cyanotoxins, a critical review is in demand. This review aims to discuss the classifications; biosynthetic pathways, especially heterogenous production; and potential applications of cyanotoxins. In detail, we first discuss the representative cyanotoxins and their toxic effects, followed by an exploration of three representative biosynthetic pathways (non-ribosomal peptide synthetases, polyketide synthetases, and their combinations). In particular, advances toward the heterologous biosynthesis of cyanotoxins in vitro and in vivo are summarized and compared. Finally, we indicate the potential applications and solutions to bottlenecks for cyanotoxins. We believe that this review will promote a comprehensive understanding, synthetic biology studies, and potential applications of cyanotoxins in the future.
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Affiliation(s)
- Zipeng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; (Z.L.); (Z.W.)
| | - Xiaofei Zhu
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China;
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; (Z.L.); (Z.W.)
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China;
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; (Z.L.); (Z.W.)
- College of Ecology and Environment, Tibet University, Lhasa 850000, China
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12
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Jacinavicius FR, Valverde Campos TG, Passos LS, Pinto E, Geraldes V. A rapid LC-MS/MS method for multi-class identification and quantification of cyanotoxins. Toxicon 2023; 234:107282. [PMID: 37678578 DOI: 10.1016/j.toxicon.2023.107282] [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: 06/26/2023] [Revised: 08/16/2023] [Accepted: 09/04/2023] [Indexed: 09/09/2023]
Abstract
Cyanobacteria can form harmful blooms in specific environmental conditions due to certain species producing toxic metabolites known as cyanotoxins. These toxins pose significant risks to public health and the environment, making it critical to identify and quantify them in food and water sources to avoid contamination. However, current screening methods only focus on a single class of cyanotoxins, limiting their effectiveness. Thus, fast and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed to analyze eighteen cyanotoxins simultaneously. A simplified extraction procedure using lyophilized samples of cyanobacterial biomass was also used, eliminating the need for traditional solid-phase extraction methods. This method uses multiple reaction monitoring and allows accurate determination and quantification of eighteen cyanotoxins, including anatoxin-a, homoanatoxin-a, cylindrospermopsin, deoxy-cylindrospermopsin, nodularin, guanitoxin, seven microcystins (RR, [D-Asp3] RR, LA, LR, LY, LW, and YR), and five saxitoxins (gonyautoxins - GTX-1&4, GTX-2&3, GTX-5), decarbamoylgonyautoxin (dcGTX-2&3), and N-Sulfocarbamoylgonyautoxin (C1&C2), all in a short acquisition time of 8 min. Therefore, this method provides a simple and efficient approach to identify and quantify harmful compounds produced by cyanobacteria. Hence, this represents the first method to detecting guanitoxin among cyanotoxins. By expanding the range of toxins analyzed, this method can help ensure high-quality food and drinking water and protect recreational users from exposure to cyanotoxins.
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Affiliation(s)
- Fernanda Rios Jacinavicius
- Laboratory of Toxins and Natural Algae Products, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Larissa Souza Passos
- Laboratory of Environmental Biogeochemistry, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Ernani Pinto
- Laboratory of Toxins and Natural Algae Products, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil; Laboratory of Environmental Biogeochemistry, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil; Center for Carbon Research in Tropical Agriculture (CCARBON - CEPID), University of São Paulo, São Paulo, Brazil.
| | - Vanessa Geraldes
- Laboratory of Toxins and Natural Algae Products, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil; Laboratory of Environmental Biogeochemistry, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
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13
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Zeng Z, Yang X, Cao Y, Pu S, Zhou X, Gu R, Zhang Y, Wu C, Luo X, He Y. High-efficiency SERS platform based on 3D porous PPDA@Au NPs as a substrate for the detection of pesticides on vegetables. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:4842-4850. [PMID: 37702073 DOI: 10.1039/d3ay00808h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Nowadays, the presence of highly toxic and persistent residues of pesticides in water and food around the world is becoming a serious problem, and so their rapid and sensitive detection is critical to human health. In this work, a 3D composite nanoparticle of porous PDA (polydopamine) microspheres and Au NPs (PPDA@Au NPs) was proposed as a SERS substrate to detect pesticides. Porous PDA as a substrate was first synthesized with F127 (Pluronic F127), dopamine hydrochloride, and 1,3,5-TMB (1,3,5-trimethylbenzene) under weakly alkaline conditions by a one-step method. Then, HAuCl4 was in situ reduced in the pores of PPDA spheres and grew sequentially for effecting the reducibility of PPDA. As a result, uniform 3D PPDA@Au NPs with "hot spots" were successfully synthesized as SERS substrates, which could effectively avoid the agglomeration of gold nanoparticles to greatly improve the sensitivity and uniformity of the SERS platform. At the same time, methyl parathion, 4-chlorophenol, and 2,4-D as representatives of pesticides were detected with the proposed PPDA@Au NP-based SERS platform, with detection limits lower than 7.26, 7.52, and 11 ng mL-1, separately. The current work presents a simple preparation method to prepare sensitive and uniform SERS platform PPDA@Au NPs, which have potential for applications in actual pesticide and drug testing.
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14
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Cordoza J, Chen PYT, Blaustein LR, Lima ST, Fiore MF, Chekan JR, Moore BS, McKinnie SMK. Mechanistic and Structural Insights into a Divergent PLP-Dependent l-Enduracididine Cyclase from a Toxic Cyanobacterium. ACS Catal 2023; 13:9817-9828. [PMID: 37497377 PMCID: PMC10367076 DOI: 10.1021/acscatal.3c01294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/21/2023] [Indexed: 07/28/2023]
Abstract
Cyclic arginine noncanonical amino acids (ncAAs) are found in several actinobacterial peptide natural products with therapeutically useful antibacterial properties. The preparation of ncAAs like enduracididine and capreomycidine currently takes multiple biosynthetic or chemosynthetic steps, thus limiting the commercial availability and applicability of these cyclic guanidine-containing amino acids. We recently discovered and characterized the biosynthetic pathway of guanitoxin, a potent freshwater cyanobacterial neurotoxin, that contains an arginine-derived cyclic guanidine phosphate within its highly polar structure. The ncAA l-enduracididine is an early intermediate in guanitoxin biosynthesis and is produced by GntC, a unique pyridoxal-5'-phosphate (PLP)-dependent enzyme. GntC catalyzes a cyclodehydration from a stereoselectively γ-hydroxylated l-arginine precursor via a reaction that functionally and mechanistically diverges from previously established actinobacterial cyclic arginine ncAA pathways. Herein, we interrogate l-enduracididine biosynthesis from the cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 using spectroscopy, stable isotope labeling techniques, and X-ray crystallography structure-guided site-directed mutagenesis. GntC initially facilitates the reversible deprotonations of the α- and β-positions of its substrate before catalyzing an irreversible diastereoselective dehydration and subsequent intramolecular cyclization. The comparison of holo- and substrate-bound GntC structures and activity assays on site-specific mutants further identified amino acid residues that contribute to the overall catalytic mechanism. These interdisciplinary efforts at structurally and functionally characterizing GntC enable an improved understanding of how nature divergently produces cyclic arginine ncAAs and generate additional tools for their biocatalytic production and downstream biological applications.
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Affiliation(s)
- Jennifer
L. Cordoza
- Department
of Chemistry and Biochemistry, University
of California, Santa
Cruz, California 95064, United States
| | - Percival Yang-Ting Chen
- Center
for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, La Jolla, California 92093, United States
| | - Linnea R. Blaustein
- Department
of Chemistry and Biochemistry, University
of California, Santa
Cruz, California 95064, United States
| | - Stella T. Lima
- Center
for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, La Jolla, California 92093, United States
- Center
for Nuclear Energy in Agriculture, University
of São Paulo, Piracicaba, São Paulo 13416-000, Brazil
| | - Marli F. Fiore
- Center
for Nuclear Energy in Agriculture, University
of São Paulo, Piracicaba, São Paulo 13416-000, Brazil
| | - Jonathan R. Chekan
- Center
for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, La Jolla, California 92093, United States
- Department
of Chemistry and Biochemistry, University
of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Bradley S. Moore
- Department
of Chemistry and Biochemistry, University
of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92903, United States
| | - Shaun M. K. McKinnie
- Department
of Chemistry and Biochemistry, University
of California, Santa
Cruz, California 95064, United States
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15
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Yancey CE, Yu F, Tripathi A, Sherman DH, Dick GJ. Expression of Microcystis Biosynthetic Gene Clusters in Natural Populations Suggests Temporally Dynamic Synthesis of Novel and Known Secondary Metabolites in Western Lake Erie. Appl Environ Microbiol 2023; 89:e0209222. [PMID: 37070981 PMCID: PMC10231183 DOI: 10.1128/aem.02092-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/02/2023] [Indexed: 04/19/2023] Open
Abstract
Microcystis spp. produce diverse secondary metabolites within freshwater cyanobacterial harmful algal blooms (cyanoHABs) around the world. In addition to the biosynthetic gene clusters (BGCs) encoding known compounds, Microcystis genomes harbor numerous BGCs of unknown function, indicating a poorly understood chemical repertoire. While recent studies show that Microcystis produces several metabolites in the lab and field, little work has focused on analyzing the abundance and expression of its broader suite of BGCs during cyanoHAB events. Here, we use metagenomic and metatranscriptomic approaches to track the relative abundance of Microcystis BGCs and their transcripts throughout the 2014 western Lake Erie cyanoHAB. The results indicate the presence of several transcriptionally active BGCs that are predicted to synthesize both known and novel secondary metabolites. The abundance and expression of these BGCs shifted throughout the bloom, with transcript abundance levels correlating with temperature, nitrate, and phosphorus concentrations and the abundance of co-occurring predatory and competitive eukaryotic microorganisms, suggesting the importance of both abiotic and biotic controls in regulating expression. This work highlights the need for understanding the chemical ecology and potential risks to human and environmental health posed by secondary metabolites that are produced but often unmonitored. It also indicates the prospects for identifying pharmaceutical-like molecules from cyanoHAB-derived BGCs. IMPORTANCE Microcystis spp. dominate cyanobacterial harmful algal blooms (cyanoHABs) worldwide and pose significant threats to water quality through the production of secondary metabolites, many of which are toxic. While the toxicity and biochemistry of microcystins and several other compounds have been studied, the broader suite of secondary metabolites produced by Microcystis remains poorly understood, leaving gaps in our understanding of their impacts on human and ecosystem health. We used community DNA and RNA sequences to track the diversity of genes encoding synthesis of secondary metabolites in natural Microcystis populations and assess patterns of transcription in western Lake Erie cyanoHABs. Our results reveal the presence of both known gene clusters that encode toxic secondary metabolites as well as novel ones that may encode cryptic compounds. This research highlights the need for targeted studies of the secondary metabolite diversity in western Lake Erie, a vital freshwater source to the United States and Canada.
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Affiliation(s)
- Colleen E. Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Fengan Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Natural Products Discovery Core, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Gregory J. Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, Ann Arbor, Michigan, USA
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16
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Yee DA, Niwa K, Perlatti B, Chen M, Li Y, Tang Y. Genome mining for unknown-unknown natural products. Nat Chem Biol 2023; 19:633-640. [PMID: 36702957 PMCID: PMC10159913 DOI: 10.1038/s41589-022-01246-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 12/20/2022] [Indexed: 01/27/2023]
Abstract
Genome mining of biosynthetic pathways with no identifiable core enzymes can lead to discovery of the so-called unknown (biosynthetic route)-unknown (molecular structure) natural products. Here we focused on a conserved fungal biosynthetic pathway that lacks a canonical core enzyme and used heterologous expression to identify the associated natural product, a highly modified cyclo-arginine-tyrosine dipeptide. Biochemical characterization of the pathway led to identification of a new arginine-containing cyclodipeptide synthase (RCDPS), which was previously annotated as a hypothetical protein and has no sequence homology to non-ribosomal peptide synthetase or bacterial cyclodipeptide synthase. RCDPS homologs are widely encoded in fungal genomes; other members of this family can synthesize diverse cyclo-arginine-Xaa dipeptides, and characterization of a cyclo-arginine-tryptophan RCDPS showed that the enzyme is aminoacyl-tRNA dependent. Further characterization of the biosynthetic pathway led to discovery of new compounds whose structures would not have been predicted without knowledge of RCDPS function.
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Affiliation(s)
- Danielle A Yee
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
- Hexagon Bio, Menlo Park, CA, USA
| | - Kanji Niwa
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Bruno Perlatti
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
- Hexagon Bio, Menlo Park, CA, USA
| | - Mengbin Chen
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Process Research and Development, Merck & Co., Inc., Rahway, NJ, USA
| | - Yuqing Li
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
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17
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Yancey CE, Mathiesen O, Dick GJ. Transcriptionally active nitrogen fixation and biosynthesis of diverse secondary metabolites by Dolichospermum and Aphanizomenon-like Cyanobacteria in western Lake Erie Microcystis blooms. HARMFUL ALGAE 2023; 124:102408. [PMID: 37164563 DOI: 10.1016/j.hal.2023.102408] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 05/12/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) in the western basin of Lake Erie are dominated by microcystin producing Microcystis spp., but other cyanobacterial taxa that coexist in these communities may play important roles in production of toxins and shaping bloom dynamics and community function. In this study, we used metagenomic and metatranscriptomic data from the 2014 western Lake Erie cyanoHAB to explore the genetic diversity and biosynthetic potential of cyanobacteria belonging to the Anabaena, Dolichospermum, Aphanizomenon (ADA) clade. We reconstructed two near-complete metagenome-assembled genomes from two distinct ADA clade species, each containing biosynthetic gene clusters that encode novel and known secondary metabolites, including those with toxic and/or known taste and odor properties, that were transcriptionally active. However, neither ADA metagenome-assembled genome contained genes encoding guanitoxins, anatoxins, or saxitoxins, which are known to be produced by ADA. The ADA cyanobacteria accounted for most of the metagenomic and metatranscriptomic reads from nitrogen fixation genes, suggesting they were the dominant N-fixers at the times and stations sampled. Despite their relatively low abundance, our results highlight the possibility that ADA taxa could influence the water quality and ecology of Microcystis blooms, although the extent of these impacts remains to be quantified.
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Affiliation(s)
- Colleen E Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA
| | - Olivia Mathiesen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA; Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 South State Road, Ann Arbor, MI 48108 USA.
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18
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Zwick CR, Renata H. Overview of Amino Acid Modifications by Iron- and α-Ketoglutarate-Dependent Enzymes. ACS Catal 2023. [DOI: 10.1021/acscatal.3c00424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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19
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Cordoza JL, Chen PYT, Blaustein LR, Lima ST, Fiore MF, Chekan JR, Moore BS, McKinnie SMK. Mechanistic and structural insights into a divergent PLP-dependent L-enduracididine cyclase from a toxic cyanobacterium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533663. [PMID: 36993528 PMCID: PMC10055224 DOI: 10.1101/2023.03.21.533663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Cyclic arginine noncanonical amino acids (ncAAs) are found in several actinobacterial peptide natural products with therapeutically useful antibacterial properties. The preparation of ncAAs like enduracididine and capreomycidine currently takes multiple biosynthetic or chemosynthetic steps, thus limiting the commercial availability and applicability of these cyclic guanidine-containing amino acids. We recently discovered and characterized the biosynthetic pathway of guanitoxin, a potent freshwater cya-nobacterial neurotoxin, that contains an arginine-derived cyclic guanidine phosphate within its highly polar structure. The ncAA L-enduracididine is an early intermediate in guanitoxin biosynthesis and is produced by GntC, a unique pyridoxal-5'-phosphate (PLP)-dependent enzyme. GntC catalyzes a cyclodehydration from a stereoselectively γ-hydroxylated L-arginine precursor via a reaction that functionally and mechanistically diverges from previously established actinobacterial cyclic arginine ncAA pathways. Herein, we interrogate L-enduracididine biosynthesis from the cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 using spectroscopic, stable isotope labeling techniques, and X-ray crystal structure-guided site-directed mutagenesis. GntC initially facilitates the reversible deprotonations of the α- and β-positions of its substrate prior to catalyzing an irreversible diastereoselective dehydration and subsequent intramolecular cyclization. The comparison of holo- and substrate bound GntC structures and activity assays on sitespecific mutants further identified amino acid residues that contribute to the overall catalytic mechanism. These interdisciplinary efforts at structurally and functionally characterizing GntC enables an improved understanding of how Nature divergently produces cyclic arginine ncAAs and generates additional tools for their biocatalytic production and downstream biological applications.
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20
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Chiang CY, Ohashi M, Tang Y. Deciphering chemical logic of fungal natural product biosynthesis through heterologous expression and genome mining. Nat Prod Rep 2023; 40:89-127. [PMID: 36125308 PMCID: PMC9906657 DOI: 10.1039/d2np00050d] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Covering: 2010 to 2022Heterologous expression of natural product biosynthetic gene clusters (BGCs) has become a widely used tool for genome mining of cryptic pathways, bottom-up investigation of biosynthetic enzymes, and engineered biosynthesis of new natural product variants. In the field of fungal natural products, heterologous expression of a complete pathway was first demonstrated in the biosynthesis of tenellin in Aspergillus oryzae in 2010. Since then, advances in genome sequencing, DNA synthesis, synthetic biology, etc. have led to mining, assignment, and characterization of many fungal BGCs using various heterologous hosts. In this review, we will highlight key examples in the last decade in integrating heterologous expression into genome mining and biosynthetic investigations. The review will cover the choice of heterologous hosts, prioritization of BGCs for structural novelty, and how shunt products from heterologous expression can reveal important insights into the chemical logic of biosynthesis. The review is not meant to be exhaustive but is rather a collection of examples from researchers in the field, including ours, that demonstrates the usefulness and pitfalls of heterologous biosynthesis in fungal natural product discovery.
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Affiliation(s)
- Chen-Yu Chiang
- Dept. of Chemical and Biomolecular Engineering, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - Masao Ohashi
- Dept. of Chemical and Biomolecular Engineering, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - Yi Tang
- Dept. of Chemical and Biomolecular Engineering, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
- Dept. of Chemistry and Biochemistry, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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21
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Hill RA, Sutherland A. Hot off the Press. Nat Prod Rep 2022. [PMID: 35929527 DOI: 10.1039/d2np90026b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as hyperispirone A from Hypericum beanii.
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Affiliation(s)
- Robert A Hill
- School of Chemistry, Glasgow University, Glasgow, UK, G12 8QQ.
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