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Lidbury IDEA, Hitchcock A, Groenhof SRM, Connolly AN, Moushtaq L. New insights in bacterial organophosphorus cycling: From human pathogens to environmental bacteria. Adv Microb Physiol 2024; 84:1-49. [PMID: 38821631 DOI: 10.1016/bs.ampbs.2023.12.003] [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] [Indexed: 06/02/2024]
Abstract
In terrestrial and aquatic ecosystems, phosphorus (P) availability controls primary production, with consequences for climate regulation and global food security. Understanding the microbial controls on the global P cycle is a prerequisite for minimising our reliance on non-renewable phosphate rock reserves and reducing pollution associated with excessive P fertiliser use. This recognised importance has reinvigorated research into microbial P cycling, which was pioneered over 75 years ago through the study of human pathogenic bacteria-host interactions. Immobilised organic P represents a significant fraction of the total P pool. Hence, microbes have evolved a plethora of mechanisms to transform this fraction into labile inorganic phosphate, the building block for numerous biological molecules. The 'genomics era' has revealed an extraordinary diversity of organic P cycling genes exist in the environment and studies going 'back to the lab' are determining how this diversity relates to function. Through this integrated approach, many hitherto unknown genes and proteins that are involved in microbial P cycling have been discovered. Not only do these fundamental discoveries push the frontier of our knowledge, but several examples also provide exciting opportunities for biotechnology and present possible solutions for improving the sustainability of how we grow our food, both locally and globally. In this review, we provide a comprehensive overview of bacterial organic P cycling, covering studies on human pathogens and how this knowledge is informing new discoveries in environmental microbiology.
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Affiliation(s)
- Ian D E A Lidbury
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom.
| | - Andrew Hitchcock
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom; Plants, Photosynthesis, and Soil, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Sophie R M Groenhof
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Alex N Connolly
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Laila Moushtaq
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
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2
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Polidore ALA, Caserio AD, Zhu L, Metcalf WW. Complete Biochemical Characterization of Pantaphos Biosynthesis Highlights an Unusual Role for a SAM-Dependent Methyltransferase. Angew Chem Int Ed Engl 2024; 63:e202317262. [PMID: 38141166 PMCID: PMC10873477 DOI: 10.1002/anie.202317262] [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: 11/13/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 12/25/2023]
Abstract
Pantaphos is small molecule virulence factor made by the plant pathogen Pantoea ananatis. An 11 gene operon, designated hvr for high virulence, is required for production of this phosphonic acid natural product, but the metabolic steps used in its production have yet to be established. Herein, we determine the complete biosynthetic pathway using a combination of bioinformatics, in vitro biochemistry and in vivo heterologous expression. Only 6 of the 11 hvr genes are needed to produce pantaphos, while a seventh is likely to be required for export. Surprisingly, the pathway involves a series of O-methylated intermediates, which are then hydrolyzed to produce the final product. The methylated intermediates are produced by an irreversible S-adenosylmethione (SAM)-dependent methyltransferase that is required to drive a thermodynamically unfavorable dehydration in the preceding step, a function not previously attributed to members of this enzyme class. Methylation of pantaphos by the same enzyme is also likely to limit its toxicity in the producing organism. The pathway also involves a novel flavin-dependent monooxygenase that differs from homologous proteins due to its endogenous flavin-reductase activity. Heterologous production of pantaphos by Escherichia coli strains expressing the minimal gene set strongly supports the in vitro biochemical data.
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Affiliation(s)
- Alexander L A Polidore
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin, Urbana, IL 61874, USA
| | - Angelica D Caserio
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin, Urbana, IL 61874, USA
| | - Lingyang Zhu
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 S Mathews Ave, Urbana, IL 61874, USA
| | - William W Metcalf
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin, Urbana, IL 61874, USA
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61874, USA
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3
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Barona-Gómez F, Chevrette MG, Hoskisson PA. On the evolution of natural product biosynthesis. Adv Microb Physiol 2023; 83:309-349. [PMID: 37507161 DOI: 10.1016/bs.ampbs.2023.05.001] [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] [Indexed: 07/30/2023]
Abstract
Natural products are the raw material for drug discovery programmes. Bioactive natural products are used extensively in medicine and agriculture and have found utility as antibiotics, immunosuppressives, anti-cancer drugs and anthelminthics. Remarkably, the natural role and what mechanisms drive evolution of these molecules is relatively poorly understood. The exponential increase in genome and chemical data in recent years, coupled with technical advances in bioinformatics and genetics have enabled progress to be made in understanding the evolution of biosynthetic gene clusters and the products of their enzymatic machinery. Here we discuss the diversity of natural products, incorporating the mechanisms that govern evolution of metabolic pathways and how this can be applied to biosynthetic gene clusters. We build on the nomenclature of natural products in terms of primary, integrated, secondary and specialised metabolism and place this within an ecology-evolutionary-developmental biology framework. This eco-evo-devo framework we believe will help to clarify the nature and use of the term specialised metabolites in the future.
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Affiliation(s)
| | - Marc G Chevrette
- Department of Microbiology and Cell Sciences, University of Florida, Museum Drive, Gainesville, FL, United States; University of Florida Genetics Institute, University of Florida, Mowry Road, Gainesville, FL, United States
| | - Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Cathedral Street, Glasgow, United Kingdom.
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4
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The functional importance of bacterial oxidative phosphonate pathways. Biochem Soc Trans 2023; 51:487-499. [PMID: 36892197 DOI: 10.1042/bst20220479] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/10/2023]
Abstract
Organophosphonates (Pns) are a unique class of natural products characterized by a highly stable C-P bond. Pns exhibit a wide array of interesting structures as well as useful bioactivities ranging from antibacterial to herbicidal. More structurally simple Pns are scavenged and catabolized by bacteria as a source of phosphorus. Despite their environmental and industrial importance, the pathways involved in the metabolism of Pns are far from being fully elucidated. Pathways that have been characterized often reveal unusual chemical transformations and new enzyme mechanisms. Among these, oxidative enzymes play an outstanding role during the biosynthesis and degradation of Pns. They are to a high extent responsible for the structural diversity of Pn secondary metabolites and for the break-down of both man-made and biogenic Pns. Here, we review our current understanding of the importance of oxidative enzymes for microbial Pn metabolism, discuss the underlying mechanistic principles, similarities, and differences between pathways. This review illustrates Pn biochemistry to involve a mix of classical redox biochemistry and unique oxidative reactions, including ring formations, rearrangements, and desaturations. Many of these reactions are mediated by specialized iron-dependent oxygenases and oxidases. Such enzymes are the key to both early pathway diversification and late-stage functionalization of complex Pns.
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5
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Ju KS, Nair SK. Convergent and divergent biosynthetic strategies towards phosphonic acid natural products. Curr Opin Chem Biol 2022; 71:102214. [PMID: 36202046 PMCID: PMC9722595 DOI: 10.1016/j.cbpa.2022.102214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 01/27/2023]
Abstract
The phosphonate class of natural products have received significant interests in the post-genomic era due to the relative ease with which their biosynthetic genes may be identified and the resultant final products be characterized. Recent large-scale studies of the elucidation and distributions of phosphonate pathways have provided a robust landscape for deciphering the underlying biosynthetic logic. A recurrent theme in phosphonate biosynthetic pathways is the interweaving of enzymatic reactions across different routes, which enables diversification to elaborate chemically novel scaffolds. Here, we provide a few vignettes of how Nature has utilized both convergent and divergent biosynthetic strategies to compile pathways for production of novel phosphonates. These examples illustrate how common intermediates may either be generated or intercepted to diversify chemical scaffolds and provides a starting point for both biotechnological and synthetic biological applications towards new phosphonates by similar combinatorial approaches.
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Affiliation(s)
- Kou-San Ju
- Department of Microbiology, The Ohio State University, Columbus OH 43210,Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus OH 43210,Infectious Diseases Institute. The Ohio State University, Columbus OH 43210,Corresponding authors: Kou-San Ju () and Satish K. Nair ()
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, IL 61801,Carl Woese Institute for Genomic Biology. University of Illinois, Urbana, IL 61801,Corresponding authors: Kou-San Ju () and Satish K. Nair ()
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6
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McHugh RE, Munnoch JT, Braes RE, McKean IJW, Giard J, Taladriz-Sender A, Peschke F, Burley GA, Roe AJ, Hoskisson PA. Biosynthesis of Aurodox, a Type III Secretion System Inhibitor from Streptomyces goldiniensis. Appl Environ Microbiol 2022; 88:e0069222. [PMID: 35867559 PMCID: PMC9361827 DOI: 10.1128/aem.00692-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/26/2022] [Indexed: 11/20/2022] Open
Abstract
The global increase in antimicrobial-resistant infections means that there is a need to develop new antimicrobial molecules and strategies to combat the issue. Aurodox is a linear polyketide natural product that is produced by Streptomyces goldiniensis, yet little is known about aurodox biosynthesis or the nature of the biosynthetic gene cluster (BGC) that encodes its production. To gain a deeper understanding of aurodox biosynthesis by S. goldiniensis, the whole genome of the organism was sequenced, revealing the presence of an 87 kb hybrid polyketide synthase/non-ribosomal peptide synthetase (PKS/NRPS) BGC. The aurodox BGC shares significant homology with the kirromycin BGC from S. collinus Tϋ 365. However, the genetic organization of the BGC differs significantly. The candidate aurodox gene cluster was cloned and expressed in a heterologous host to demonstrate that it was responsible for aurodox biosynthesis and disruption of the primary PKS gene (aurAI) abolished aurodox production. These data supported a model whereby the initial core biosynthetic reactions involved in aurodox biosynthesis followed that of kirromycin. Cloning aurM* from S. goldiniensis and expressing this in the kirromycin producer S. collinus Tϋ 365 enabled methylation of the pyridone group, suggesting this is the last step in biosynthesis. This methylation step is also sufficient to confer the unique type III secretion system inhibitory properties to aurodox. IMPORTANCE Enterohemorrhagic Escherichia coli (EHEC) is a significant global pathogen for which traditional antibiotic treatment is not recommended. Aurodox inhibits the ability of EHEC to establish infection in the host gut through the specific targeting of the type III secretion system while circumventing the induction of toxin production associated with traditional antibiotics. These properties suggest aurodox could be a promising anti-virulence compound for EHEC, which merits further investigation. Here, we characterized the aurodox biosynthetic gene cluster from Streptomyces goldiniensis and established the key enzymatic steps of aurodox biosynthesis that give rise to the unique anti-virulence activity. These data provide the basis for future chemical and genetic approaches to produce aurodox derivatives with increased efficacy and the potential to engineer novel elfamycins.
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Affiliation(s)
- Rebecca E. McHugh
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - John T. Munnoch
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Robyn E. Braes
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Iain J. W. McKean
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
| | - Josephine Giard
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | - Frederik Peschke
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
| | - Glenn A. Burley
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
| | - Andrew J. Roe
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Paul A. Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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7
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Characterization of the cobalamin-dependent radical S-adenosyl-l-methionine enzyme C-methyltransferase Fom3 in fosfomycin biosynthesis. Methods Enzymol 2022; 669:45-70. [PMID: 35644180 DOI: 10.1016/bs.mie.2021.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fosfomycin is a clinically used broad-spectrum antibiotic that has the structure of an oxirane ring with a phosphonic acid substituent and a methyl substituent. In nature, fosfomycin is produced by Streptomyces spp. and Pseudomonas sp., but biosynthesis of fosfomycin significantly differs between the two bacteria, especially in the incorporation mechanism of the methyl group. It has been proposed that the cobalamin-dependent radical S-adenosyl-l-methionine (SAM) enzyme Fom3 is responsible for the methyl-transfer reaction in Streptomyces fosfomycin biosynthesis. In this chapter, we describe the experimental methods to characterize Fom3. We performed the methylation reaction with the purified recombinant Fom3, revealing that Fom3 recognizes a cytidylylated 2-hydroxyethylphosphonate as a substrate and catalyzes stereoselective methylation of the sp3 carbon at the C2 position to afford cytidylylated (S)-2-hydroxypropylphosphonate. Reaction analysis using deuterium-labeled substrates showed that the 5'-deoxyadenosyl radical generated by reductive cleavage of SAM stereoselectively abstracts the pro-R hydrogen atom of the CH bond at the C2 position of cytidylylated 2-hydroxyethylphosphonate. Therefore, the C-methylation reaction catalyzed by Fom3 proceeds with inversion of the configuration at the C2 position. Experimental methods to elucidate the chemical structures of the substrate and products and the stereochemical course in the Fom3-catalyzed reaction could give information to progress investigation of cobalamin-dependent radical SAM C-methyltransferases.
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8
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Gupta D, Shalvarjian KE, Nayak DD. An archaea-specific c-type cytochrome maturation machinery is crucial for methanogenesis in Methanosarcina acetivorans. eLife 2022; 11:76970. [PMID: 35380107 PMCID: PMC9084895 DOI: 10.7554/elife.76970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
c-Type cytochromes (cyt c) are proteins that undergo post-translational modification to covalently bind heme, which allows them to facilitate redox reactions in electron transport chains across all domains of life. Genomic evidence suggests that cyt c are involved in electron transfer processes among the Archaea, especially in members that produce or consume the potent greenhouse gas methane. However, neither the maturation machinery for cyt c in Archaea nor their role in methane metabolism has ever been functionally characterized. Here, we have used CRISPR-Cas9 genome editing tools to map a distinct pathway for cyt c biogenesis in the model methanogenic archaeon Methanosarcina acetivorans, and have also identified substrate-specific functional roles for cyt c during methanogenesis. Although the cyt c maturation machinery from M. acetivorans is universally conserved in the Archaea, our evolutionary analyses indicate that different clades of Archaea acquired this machinery through multiple independent horizontal gene transfer events from different groups of Bacteria. Overall, we demonstrate the convergent evolution of a novel Archaea-specific cyt c maturation machinery and its physiological role during methanogenesis, a process which contributes substantially to global methane emissions. Archaea are single-celled organisms that were discovered over half a century ago. Recently, there has been a renewed interest in these microbes because theyplay a key role in climate change by controlling greenhouse gas emissions, like methane. Indeed, methane-producing Archaea generate nearly 70% of the methane gas released into the atmosphere. A group of proteins called c-type cytochromes are essential to energy generation in several methane-producing archaea. However, it is a mystery how Archaea assemble their c-type cytochromes. In fact, genomic studies suggest that Archaea are missing some of the c-type cytochrome assembly machinery that bacteria use. This has led scientists to suspect that Archaea have an alternate mechanism for building these essential components. To solve this mystery, Gupta, Shalvarjian, and Nayak used CRISPR-Cas9 gene-editing tools to characterize which proteins are essential for c-type cytochrome production in Methanosarcina acetivorans, a species of Archaea that produces methane. These experiments showed that M. acetivorans discarded a few parts of the process used by bacteria to generate c-type cytochromes, streamlining the assembly of these proteins. By comparing the genes of different Archaeal species, Gupta, Shalvarjian and Nayak were able to determine that Archaea acquired the genes for producing c-type cytochromes from bacteria via horizontal gene transfer, a process in which genes move directly from one organism into another. The streamlining of the process took place later, as different Archaeal species evolved independently, but losing the same parts of the process. Gupta Shalvajiran and Nayak’s experiments also showed that c-type cytochromes are essential for the growth and fitness of methane-producing Archaea like M. acetivorans. The role of c-type cytochromes in methane production varies in different species of Archaea depending on their growth substrate or where they live. These results provide vital information about how Archaea produce methane, and the tools and techniques developed will aid further investigation of the role of Archaea in climate change.
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Affiliation(s)
- Dinesh Gupta
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Katie E Shalvarjian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Dipti D Nayak
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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9
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Abstract
Microbial phosphonate biosynthetic machinery has been identified in ~5 % of bacterial genomes and encodes natural products like fosfomycin as well as cell surface decorations. Almost all biological phosphonates originate from the rearrangement of phosphoenolpyruvate (PEP) to phosphonopyruvate (PnPy) catalysed by PEP mutase (Ppm), and PnPy is often converted to phosphonoacetaldehyde (PnAA) by PnPy decarboxylase (Ppd). Seven enzymes are known or likely to act on either PnPy or PnAA as early branch points en route to diverse biosynthetic outcomes, and these enzymes may be broadly classified into three reaction types: hydride transfer, aminotransfer, and carbon-carbon bond formation. However, the relative abundance of these branch points in microbial phosphonate biosynthesis is unknown. Also unknown is the proportion of ppm-containing gene neighbourhoods encoding new branch point enzymes and potentially novel phosphonates. In this study we computationally sorted 434 ppm-containing gene neighbourhoods based on these seven branch point enzymes. Unsurprisingly, the majority (56 %) of these pathways encode for production of the common naturally occurring compound 2-aminoethylphosphonate (AEP) or a hydroxylated derivative. The next most abundant genetically encoded intermediates were phosphonoalanine (PnAla, 9.2 %), 2-hydroxyethylphosphonate (HEP, 8.5 %), and phosphonoacetate (PnAc, 6 %). Significantly, about 13 % of the gene neighbourhoods could not be assigned to any of the seven branch points and may encode novel phosphonates. Sequence similarity network analysis revealed families of unusual gene neighbourhoods including possible production of phosphonoacrylate and phosphonofructose, the apparent biosynthetic use of the C-P lyase operon, and a virus-encoded phosphonate. Overall, these results highlight the utility of branch point inventories to identify novel gene neighbourhoods and guide future phosphonate discovery efforts.
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Affiliation(s)
- Siwei Li
- Department of Chemistry & Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
| | - Geoff P. Horsman
- Department of Chemistry & Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
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10
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Santos-Aberturas J, Vior NM. Beyond Soil-Dwelling Actinobacteria: Fantastic Antibiotics and Where to Find Them. Antibiotics (Basel) 2022; 11:195. [PMID: 35203798 PMCID: PMC8868522 DOI: 10.3390/antibiotics11020195] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/10/2022] Open
Abstract
Bacterial secondary metabolites represent an invaluable source of bioactive molecules for the pharmaceutical and agrochemical industries. Although screening campaigns for the discovery of new compounds have traditionally been strongly biased towards the study of soil-dwelling Actinobacteria, the current antibiotic resistance and discovery crisis has brought a considerable amount of attention to the study of previously neglected bacterial sources of secondary metabolites. The development and application of new screening, sequencing, genetic manipulation, cultivation and bioinformatic techniques have revealed several other groups of bacteria as producers of striking chemical novelty. Biosynthetic machineries evolved from independent taxonomic origins and under completely different ecological requirements and selective pressures are responsible for these structural innovations. In this review, we summarize the most important discoveries related to secondary metabolites from alternative bacterial sources, trying to provide the reader with a broad perspective on how technical novelties have facilitated the access to the bacterial metabolic dark matter.
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Affiliation(s)
| | - Natalia M. Vior
- Department of Molecular Microbiology, John Innes Centre, Norwich NR7 4UH, UK
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11
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Differences in fosfomycin resistance mechanisms between Pseudomonas aeruginosa and Enterobacterales. Antimicrob Agents Chemother 2021; 66:e0144621. [PMID: 34807759 DOI: 10.1128/aac.01446-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidrug-resistant (MDR) Pseudomonas aeruginosa presents a serious threat to public health due to its widespread resistance to numerous antibiotics. P. aeruginosa commonly causes nosocomial infections including urinary tract infections (UTI) which have become increasingly difficult to treat. The lack of effective therapeutic agents has renewed interest in fosfomycin, an old drug discovered in the 1960s and approved prior to the rigorous standards now required for drug approval. Fosfomycin has a unique structure and mechanism of action, making it a favorable therapeutic alternative for MDR pathogens that are resistant to other classes of antibiotics. The absence of susceptibility breakpoints for fosfomycin against P. aeruginosa limits its clinical use and interpretation due to extrapolation of breakpoints established for Escherichia coli or Enterobacterales without supporting evidence. Furthermore, fosfomycin use and efficacy for treatment of P. aeruginosa is also limited by both inherent and acquired resistance mechanisms. This narrative review provides an update on currently identified resistance mechanisms to fosfomycin, with a focus on those mediated by P. aeruginosa such as peptidoglycan recycling enzymes, chromosomal Fos enzymes, and transporter mutation. Additional fosfomycin resistance mechanisms exhibited by Enterobacterales including mutations in transporters and associated regulators, plasmid mediated Fos enzymes, kinases, and murA modification, are also summarized and contrasted. These data highlight that different fosfomycin resistance mechanisms may be associated with elevated MIC values in P. aeruginosa compared to Enterobacterales, emphasizing that extrapolation of E. coli breakpoints to P. aeruginosa should be avoided.
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Pacheco-Moreno A, Stefanato FL, Ford JJ, Trippel C, Uszkoreit S, Ferrafiat L, Grenga L, Dickens R, Kelly N, Kingdon AD, Ambrosetti L, Nepogodiev SA, Findlay KC, Cheema J, Trick M, Chandra G, Tomalin G, Malone JG, Truman AW. Pan-genome analysis identifies intersecting roles for Pseudomonas specialized metabolites in potato pathogen inhibition. eLife 2021; 10:71900. [PMID: 34792466 PMCID: PMC8719888 DOI: 10.7554/elife.71900] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/16/2021] [Indexed: 11/29/2022] Open
Abstract
Agricultural soil harbors a diverse microbiome that can form beneficial relationships with plants, including the inhibition of plant pathogens. Pseudomonas spp. are one of the most abundant bacterial genera in the soil and rhizosphere and play important roles in promoting plant health. However, the genetic determinants of this beneficial activity are only partially understood. Here, we genetically and phenotypically characterize the Pseudomonas fluorescens population in a commercial potato field, where we identify strong correlations between specialized metabolite biosynthesis and antagonism of the potato pathogens Streptomyces scabies and Phytophthora infestans. Genetic and chemical analyses identified hydrogen cyanide and cyclic lipopeptides as key specialized metabolites associated with S. scabies inhibition, which was supported by in planta biocontrol experiments. We show that a single potato field contains a hugely diverse and dynamic population of Pseudomonas bacteria, whose capacity to produce specialized metabolites is shaped both by plant colonization and defined environmental inputs. Potato scab and blight are two major diseases which can cause heavy crop losses. They are caused, respectively, by the bacterium Streptomyces scabies and an oomycete (a fungus-like organism) known as Phytophthora infestans. Fighting these disease-causing microorganisms can involve crop management techniques – for example, ensuring that a field is well irrigated helps to keep S. scabies at bay. Harnessing biological control agents can also offer ways to control disease while respecting the environment. Biocontrol bacteria, such as Pseudomonas, can produce compounds that keep S. scabies and P. infestans in check. However, the identity of these molecules and how irrigation can influence Pseudomonas population remains unknown. To examine these questions, Pacheco-Moreno et al. sampled and isolated hundreds of Pseudomonas strains from a commercial potato field, closely examining the genomes of 69 of these. Comparing the genetic information of strains based on whether they could control the growth of S. scabies revealed that compounds known as cyclic lipopeptides are key to controlling the growth of S. scabies and P. infestans. Whether the field was irrigated also had a large impact on the strains forming the Pseudomonas population. Working out how Pseudomonas bacteria block disease could speed up the search for biological control agents. The approach developed by Pacheco-Moreno et al. could help to predict which strains might be most effective based on their genetic features. Similar experiments could also work for other combinations of plants and diseases.
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Affiliation(s)
- Alba Pacheco-Moreno
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jonathan J Ford
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Christine Trippel
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Simon Uszkoreit
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Laura Ferrafiat
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Lucia Grenga
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Ruth Dickens
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Nathan Kelly
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Alexander Dh Kingdon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Liana Ambrosetti
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich, United Kingdom
| | - Kim C Findlay
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Jitender Cheema
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Martin Trick
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
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Simon MA, Ongpipattanakul C, Nair SK, van der Donk WA. Biosynthesis of fosfomycin in pseudomonads reveals an unexpected enzymatic activity in the metallohydrolase superfamily. Proc Natl Acad Sci U S A 2021; 118:e2019863118. [PMID: 34074759 PMCID: PMC8201877 DOI: 10.1073/pnas.2019863118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The epoxide-containing phosphonate natural product fosfomycin is a broad-spectrum antibiotic used in the treatment of cystitis. Fosfomycin is produced by both the plant pathogen Pseudomonas syringae and soil-dwelling streptomycetes. While the streptomycete pathway has recently been fully elucidated, the pseudomonad pathway is still mostly elusive. Through a systematic evaluation of heterologous expression of putative biosynthetic enzymes, we identified the central enzyme responsible for completing the biosynthetic pathway in pseudomonads. The missing transformation involves the oxidative decarboxylation of the intermediate 2-phosphonomethylmalate to a new intermediate, 3-oxo-4-phosphonobutanoate, by PsfC. Crystallographic studies reveal that PsfC unexpectedly belongs to a new class of diiron metalloenzymes that are part of the polymerase and histidinol phosphatase superfamily.
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Affiliation(s)
- Max A Simon
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Chayanid Ongpipattanakul
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Satish K Nair
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Wilfred A van der Donk
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- HHMI, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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14
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McLaughlin M, Pallitsch K, Wallner G, van der Donk WA, Hammerschmidt F. Overall Retention of Methyl Stereochemistry during B 12-Dependent Radical SAM Methyl Transfer in Fosfomycin Biosynthesis. Biochemistry 2021; 60:1587-1596. [PMID: 33942609 PMCID: PMC8158854 DOI: 10.1021/acs.biochem.1c00113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/24/2021] [Indexed: 11/30/2022]
Abstract
Methylcobalamin-dependent radical S-adenosylmethionine (SAM) enzymes methylate non-nucleophilic atoms in a range of substrates. The mechanism of the methyl transfer from cobalt to the receiving atom is still mostly unresolved. Here we determine the stereochemical course of this process at the methyl group during the biosynthesis of the clinically used antibiotic fosfomycin. In vitro reaction of the methyltransferase Fom3 using SAM labeled with 1H, 2H, and 3H in a stereochemically defined manner, followed by chemoenzymatic conversion of the Fom3 product to acetate and subsequent stereochemical analysis, shows that the overall reaction occurs with retention of configuration. This outcome is consistent with a double-inversion process, first in the SN2 reaction of cob(I)alamin with SAM to form methylcobalamin and again in a radical transfer of the methyl group from methylcobalamin to the substrate. The methods developed during this study allow high-yield in situ generation of labeled SAM and recombinant expression and purification of the malate synthase needed for chiral methyl analysis. These methods facilitate the broader use of in vitro chiral methyl analysis techniques to investigate the mechanisms of other novel enzymes.
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Affiliation(s)
- Martin
I. McLaughlin
- Department
of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | | | - Gabriele Wallner
- Institute
of Inorganic Chemistry, University of Vienna, Vienna 1090, Austria
| | - Wilfred A. van der Donk
- Department
of Chemistry and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Howard
Hughes Medical Institute, University of
Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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15
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Shiraishi T, Kuzuyama T. Biosynthetic pathways and enzymes involved in the production of phosphonic acid natural products. Biosci Biotechnol Biochem 2021; 85:42-52. [PMID: 33577658 DOI: 10.1093/bbb/zbaa052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/04/2020] [Indexed: 02/07/2023]
Abstract
Phosphonates are organophosphorus compounds possessing a characteristic C-P bond in which phosphorus is directly bonded to carbon. As phosphonates mimic the phosphates and carboxylates of biological molecules to potentially inhibit metabolic enzymes, they could be lead compounds for the development of a variety of drugs. Fosfomycin (FM) is a representative phosphonate natural product that is widely used as an antibacterial drug. Here, we review the biosynthesis of FM, which includes a recent breakthrough to find a missing link in the biosynthetic pathway that had been a mystery for a quarter-century. In addition, we describe the genome mining of phosphonate natural products using the biosynthetic gene encoding an enzyme that catalyzes C-P bond formation. We also introduce the chemoenzymatic synthesis of phosphonate derivatives. These studies expand the repertoires of phosphonates and the related biosynthetic machinery. This review mainly covers the years 2012-2020.
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Affiliation(s)
- Taro Shiraishi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tomohisa Kuzuyama
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology (CRIIM), The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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16
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Abstract
Microbial natural products, particularly those produced by filamentous Actinobacteria, underpin the majority of clinically used antibiotics. Unfortunately, only a few new antibiotic classes have been discovered since the 1970s, which has exacerbated fears of a postapocalyptic world in which antibiotics have lost their utility. Excitingly, the genome sequencing revolution painted an entirely new picture, one in which an average strain of filamentous Actinobacteria harbors 20 to 50 natural product biosynthetic pathways but expresses very few of these under laboratory conditions. Microbial natural products, particularly those produced by filamentous Actinobacteria, underpin the majority of clinically used antibiotics. Unfortunately, only a few new antibiotic classes have been discovered since the 1970s, which has exacerbated fears of a postapocalyptic world in which antibiotics have lost their utility. Excitingly, the genome sequencing revolution painted an entirely new picture, one in which an average strain of filamentous Actinobacteria harbors 20 to 50 natural product biosynthetic pathways but expresses very few of these under laboratory conditions. Development of methodology to access this “hidden” biochemical diversity has the potential to usher in a second Golden Era of antibiotic discovery. The proliferation of genomic data has led to inconsistent use of “cryptic” and “silent” when referring to biosynthetic gene clusters identified by bioinformatic analysis. In this Perspective, we discuss this issue and propose to formalize the use of this terminology.
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17
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Zhou C, Luo X, Chen N, Zhang L, Gao J. C-P Natural Products as Next-Generation Herbicides: Chemistry and Biology of Glufosinate. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:3344-3353. [PMID: 32125843 DOI: 10.1021/acs.jafc.0c00052] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In modern agriculture and weed management practices, herbicides have been widely used to control weeds effectively and represent more than 50% of commercial pesticides applied in the world. Herbicides with unique mechanisms of actions (MOA) have historically been discovered and commercialized every two or three years from the 1950s to the 1980s. However, this trend lowered dramatically as no herbicide with a novel MOA has been marketed for more than 30 years. The fast-growing resistance to commercial herbicides has reignited the agricultural chemical industry interest in new structural scaffolds targeting novel sites in plants. Carbon-phosphorus bonds (C-P) containing natural products (NPs) have played an essential role in herbicide discovery as the chemical diversity, and the promising bioactivity of natural C-P phytotoxins can provide exciting opportunities for the discovery of both natural and semisynthetic herbicides with novel targets. Among commercial herbicides, glyphosate (Roundup), a famous C-P containing herbicide, is by far the most universally used herbicide worldwide. Furthermore, glufosinate is one of the most widely used natural herbicides in the world. Therefore, C-P NPs are a treasure for discovering new herbicides with novel mechanisms of actions (MOAs). Here, we present an overview of the chemistry and biology of glufosinate including isolation and characterization, mode of action, herbicidal use, biosynthesis, and chemical synthesis since its discovery in order to not only help scientists reassess the role of this famous herbicide in the field of agrichemical chemistry but also build a new stage for discovering novel C-P herbicides with new MOAs.
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Affiliation(s)
- Chengzeng Zhou
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiaoxia Luo
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production & Construction Corps, College of Life Science, Tarim University, Alar 843300, China
| | - Nengyi Chen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lili Zhang
- Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin of Xinjiang Production & Construction Corps, College of Life Science, Tarim University, Alar 843300, China
| | - Jiangtao Gao
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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18
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Nayak DD, Liu A, Agrawal N, Rodriguez-Carerro R, Dong SH, Mitchell DA, Nair SK, Metcalf WW. Functional interactions between posttranslationally modified amino acids of methyl-coenzyme M reductase in Methanosarcina acetivorans. PLoS Biol 2020; 18:e3000507. [PMID: 32092071 PMCID: PMC7058361 DOI: 10.1371/journal.pbio.3000507] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/05/2020] [Accepted: 02/04/2020] [Indexed: 01/27/2023] Open
Abstract
The enzyme methyl-coenzyme M reductase (MCR) plays an important role in mediating global levels of methane by catalyzing a reversible reaction that leads to the production or consumption of this potent greenhouse gas in methanogenic and methanotrophic archaea. In methanogenic archaea, the alpha subunit of MCR (McrA) typically contains four to six posttranslationally modified amino acids near the active site. Recent studies have identified enzymes performing two of these modifications (thioglycine and 5-[S]-methylarginine), yet little is known about the formation and function of the remaining posttranslationally modified residues. Here, we provide in vivo evidence that a dedicated S-adenosylmethionine-dependent methyltransferase encoded by a gene we designated methylcysteine modification (mcmA) is responsible for formation of S-methylcysteine in Methanosarcina acetivorans McrA. Phenotypic analysis of mutants incapable of cysteine methylation suggests that the S-methylcysteine residue might play a role in adaption to mesophilic conditions. To examine the interactions between the S-methylcysteine residue and the previously characterized thioglycine, 5-(S)-methylarginine modifications, we generated M. acetivorans mutants lacking the three known modification genes in all possible combinations. Phenotypic analyses revealed complex, physiologically relevant interactions between the modified residues, which alter the thermal stability of MCR in a combinatorial fashion that is not readily predictable from the phenotypes of single mutants. High-resolution crystal structures of inactive MCR lacking the modified amino acids were indistinguishable from the fully modified enzyme, suggesting that interactions between the posttranslationally modified residues do not exert a major influence on the static structure of the enzyme but rather serve to fine-tune the activity and efficiency of MCR.
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Affiliation(s)
- Dipti D. Nayak
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Andi Liu
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Neha Agrawal
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Roy Rodriguez-Carerro
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Shi-Hui Dong
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Douglas A. Mitchell
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
- Center for Biophysics & Quantitative Biology, University of Illinois, Urbana, Illinois, United States of America
| | - William W. Metcalf
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
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19
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Cao Y, Peng Q, Li S, Deng Z, Gao J. The intriguing biology and chemistry of fosfomycin: the only marketed phosphonate antibiotic. RSC Adv 2019; 9:42204-42218. [PMID: 35548698 PMCID: PMC9088020 DOI: 10.1039/c9ra08299a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/27/2019] [Indexed: 11/29/2022] Open
Abstract
Recently infectious diseases caused by the increased emergence and rapid spread of drug-resistant bacterial isolates have been one of the main threats to global public health because of a marked surge in both morbidity and mortality. The only phosphonate antibiotic in the clinic, fosfomycin, is a small broad-spectrum molecule that effectively inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme, MurA in both Gram-positive and Gram-negative bacteria. As fosfomycin has a novel mechanism of action, low toxicity, a broad spectrum of antibacterial activity, excellent pharmacodynamic/pharmacokinetic properties, and good bioavailability, it has been approved for clinical use in the treatment of urinary tract bacterial infections in many countries for several decades. Furthermore, its potential use for difficult-to-treat bacterial infections has become promising, and fosfomycin has become an ideal candidate for the effective treatment of bacterial infections caused by multidrug-resistant isolates, especially in combination with other therapeutic drugs. Here we aim to present an overview of the biology and chemistry of fosfomycin including isolation and characterization, pharmacology, biosynthesis and chemical synthesis since its discovery in order to not only help scientists reassess the role of this exciting drug in fighting antibiotic resistance but also build the stage for discovering more novel phosphonate antibiotics in the future.
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Affiliation(s)
- Yingying Cao
- College of Life Sciences, Fujian Agriculture and Forestry University Fuzhou 350002 China
| | - Qingyao Peng
- College of Life Sciences, Fujian Agriculture and Forestry University Fuzhou 350002 China
| | - Shanni Li
- College of Life Sciences, Fujian Agriculture and Forestry University Fuzhou 350002 China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Jiangtao Gao
- College of Life Sciences, Fujian Agriculture and Forestry University Fuzhou 350002 China
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20
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Chevrette MG, Gutiérrez-García K, Selem-Mojica N, Aguilar-Martínez C, Yañez-Olvera A, Ramos-Aboites HE, Hoskisson PA, Barona-Gómez F. Evolutionary dynamics of natural product biosynthesis in bacteria. Nat Prod Rep 2019; 37:566-599. [PMID: 31822877 DOI: 10.1039/c9np00048h] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Covering: 2008 up to 2019The forces of biochemical adaptive evolution operate at the level of genes, manifesting in complex phenotypes and the global biodiversity of proteins and metabolites. While evolutionary histories have been deciphered for some other complex traits, the origins of natural product biosynthesis largely remain a mystery. This fundamental knowledge gap is surprising given the many decades of research probing the genetic, chemical, and biophysical mechanisms of bacterial natural product biosynthesis. Recently, evolutionary thinking has begun to permeate this otherwise mechanistically dominated field. Natural products are now sometimes referred to as 'specialized' rather than 'secondary' metabolites, reinforcing the importance of their biological and ecological functions. Here, we review known evolutionary mechanisms underlying the overwhelming chemical diversity of bacterial secondary metabolism, focusing on enzyme promiscuity and the evolution of enzymatic domains that enable metabolic traits. We discuss the mechanisms that drive the assembly of natural product biosynthetic gene clusters and propose formal definitions for 'specialized' and 'secondary' metabolism. We further explore how biosynthetic gene clusters evolve to synthesize related molecular species, and in turn how the biological and ecological roles that emerge from metabolic diversity are acted on by selection. Finally, we reconcile chemical, functional, and genetic data into an evolutionary model, the dynamic chemical matrix evolutionary hypothesis, in which the relationships between chemical distance, biomolecular activity, and relative fitness shape adaptive landscapes.
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Affiliation(s)
- Marc G Chevrette
- Wisconsin Institute for Discovery, Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
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21
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GDGT cyclization proteins identify the dominant archaeal sources of tetraether lipids in the ocean. Proc Natl Acad Sci U S A 2019; 116:22505-22511. [PMID: 31591189 DOI: 10.1073/pnas.1909306116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glycerol dibiphytanyl glycerol tetraethers (GDGTs) are distinctive archaeal membrane-spanning lipids with up to eight cyclopentane rings and/or one cyclohexane ring. The number of rings added to the GDGT core structure can vary as a function of environmental conditions, such as changes in growth temperature. This physiological response enables cyclic GDGTs preserved in sediments to be employed as proxies for reconstructing past global and regional temperatures and to provide fundamental insights into ancient climate variability. Yet, confidence in GDGT-based paleotemperature proxies is hindered by uncertainty concerning the archaeal communities contributing to GDGT pools in modern environments and ambiguity in the environmental and physiological factors that affect GDGT cyclization in extant archaea. To properly constrain these uncertainties, a comprehensive understanding of GDGT biosynthesis is required. Here, we identify 2 GDGT ring synthases, GrsA and GrsB, essential for GDGT ring formation in Sulfolobus acidocaldarius Both proteins are radical S-adenosylmethionine proteins, indicating that GDGT cyclization occurs through a free radical mechanism. In addition, we demonstrate that GrsA introduces rings specifically at the C-7 position of the core GDGT lipid, while GrsB cyclizes at the C-3 position, suggesting that cyclization patterns are differentially controlled by 2 separate enzymes and potentially influenced by distinct environmental factors. Finally, phylogenetic analyses of the Grs proteins reveal that marine Thaumarchaeota, and not Euryarchaeota, are the dominant source of cyclized GDGTs in open ocean settings, addressing a major source of uncertainty in GDGT-based paleotemperature proxy applications.
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22
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Nayak DD, Metcalf WW. Methylamine-specific methyltransferase paralogs in Methanosarcina are functionally distinct despite frequent gene conversion. THE ISME JOURNAL 2019; 13:2173-2182. [PMID: 31053830 PMCID: PMC6776008 DOI: 10.1038/s41396-019-0428-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/28/2019] [Accepted: 04/03/2019] [Indexed: 11/09/2022]
Abstract
Sequenced archaeal genomes are mostly smaller and more streamlined than typical bacterial genomes; however, members of the Methanosarcina genus within the Euryarchaeaota are a significant exception, with M. acetivorans being the largest archaeal genome (5.8 Mbp) sequenced thus far. This finding is partially explained by extensive gene duplication within Methanosarcina spp. Significantly, the evolutionary pressures leading to gene duplication and subsequent genome expansion have not been well investigated, especially with respect to biological methane production (methanogenesis), which is the key biological trait of these environmentally important organisms. In this study, we address this question by specifically probing the functional evolution of two methylamine-specific methyltransferase paralogs in members of the Methanosarcina genus. Using the genetically tractable strain, M. acetivorans, we first show that the two paralogs have distinct cellular functions: one being required for methanogenesis from methylamine, the other for use of methylamine as a nitrogen source. Subsequently, through comparative sequence analyses, we show that functional divergence of paralogs is primarily mediated by divergent evolution of the 5' regulatory region, despite frequent gene conversion within the coding sequence. This unique evolutionary paradigm for functional divergence of genes post-duplication underscores a divergent role for an enzyme singularly associated with methanogenic metabolism in other aspects of cell physiology.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois, 1206 W. Gregory Drive, Urbana, IL, 61801, USA.
| | - William W Metcalf
- Department of Microbiology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA
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23
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Farley KR, Metcalf WW. The streptothricin acetyltransferase (sat) gene as a positive selectable marker for methanogenic archaea. FEMS Microbiol Lett 2019; 366:5586563. [PMID: 31605529 DOI: 10.1093/femsle/fnz216] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/10/2019] [Indexed: 11/14/2022] Open
Abstract
A repertoire of sophisticated genetic tools has significantly enhanced studies of Methanosarcina genera, yet the lack of multiple positive selectable markers has limited the types of genetic experiments that can be performed. In this study, we report the development of an additional positive selection system for Methanosarcina that utilizes the antibiotic nourseothricin and the Streptomyces rochei streptothricin acetyltransferase (sat) gene, which may be broadly applicable to other groups of methanogenic archaea. Nourseothricin was found to inhibit growth of four different methanogen species at concentrations ≤300 μg/ml in liquid or on solid media. Selection of nourseothricin resistant transformants was possible in two genetically tractable Methanosarcina species, M. acetivorans and M. barkeri, using the sat gene as a positive selectable marker. Additionally, the sat marker was useful for constructing a gene deletion mutant strain of M. acetivorans, emphasizing its utility as a second positive selectable marker for genetic analyses of Methanosarcina genera. Interestingly, two human gut-associated methanogens Methanobrevibacter smithii and Methanomassillicoccus luminyensis were more sensitive to nourseothricin than either Methanosarcina species, suggesting the nourseothricin-sat gene pair may provide a robust positive selection system for development of genetic tools in these and other methanogens.
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Affiliation(s)
- Kristen R Farley
- Department of Microbiology, B103 Chemical and Life Sciences Laboratory, University of Illinois Urbana-Champaign, 601 S. Goodwin Avenue, Urbana, Illinois 61801
| | - William W Metcalf
- Department of Microbiology, B103 Chemical and Life Sciences Laboratory, University of Illinois Urbana-Champaign, 601 S. Goodwin Avenue, Urbana, Illinois 61801
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24
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Parkinson EI, Erb A, Eliot AC, Ju KS, Metcalf WW. Fosmidomycin biosynthesis diverges from related phosphonate natural products. Nat Chem Biol 2019; 15:1049-1056. [PMID: 31451762 PMCID: PMC7098449 DOI: 10.1038/s41589-019-0343-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/09/2019] [Indexed: 12/04/2022]
Abstract
Fosmidomycin and related molecules comprise a family of phosphonate natural products with potent antibacterial, antimalarial and herbicidal activities. To understand the biosynthesis of these compounds, we characterized the fosmidomycin producer, Streptomyces lavendulae, using biochemical and genetic approaches. Surprisingly, we were unable to elicit production of fosmidomycin, instead observing the unsaturated derivative dehydrofosmidomycin, which we showed potently inhibits 1-deoxy-D-xylulose 5-phosphate reductoisomerase and has bioactivity against a number of bacteria. The genes required for dehydrofosmidomycin biosynthesis were established by heterologous expression experiments. Bioinformatics analyses, characterization of intermediates, and in vitro biochemistry show that the biosynthetic pathway involves conversion of a two-carbon phosphonate precursor into the unsaturated three-carbon product via a highly unusual rearrangement reaction, catalyzed by the 2-oxoglutarate dependent dioxygenase DfmD. The required genes and biosynthetic pathway for dehydrofosmidomycin differ substantially from that of the related natural product FR-900098, suggesting that the ability to produce these bioactive molecules arose via convergent evolution.
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Affiliation(s)
- Elizabeth I Parkinson
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Annette Erb
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Andrew C Eliot
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kou-San Ju
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Microbiology and the Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, OH, USA
| | - William W Metcalf
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA. .,Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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25
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Abstract
During the past decades resistance to virtually all antimicrobial agents has been observed in bacteria of animal origin. This chapter describes in detail the mechanisms so far encountered for the various classes of antimicrobial agents. The main mechanisms include enzymatic inactivation by either disintegration or chemical modification of antimicrobial agents, reduced intracellular accumulation by either decreased influx or increased efflux of antimicrobial agents, and modifications at the cellular target sites (i.e., mutational changes, chemical modification, protection, or even replacement of the target sites). Often several mechanisms interact to enhance bacterial resistance to antimicrobial agents. This is a completely revised version of the corresponding chapter in the book Antimicrobial Resistance in Bacteria of Animal Origin published in 2006. New sections have been added for oxazolidinones, polypeptides, mupirocin, ansamycins, fosfomycin, fusidic acid, and streptomycins, and the chapters for the remaining classes of antimicrobial agents have been completely updated to cover the advances in knowledge gained since 2006.
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26
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Nayak DD, Metcalf WW. Genetic techniques for studies of methyl-coenzyme M reductase from Methanosarcina acetivorans C2A. Methods Enzymol 2018; 613:325-347. [PMID: 30509472 DOI: 10.1016/bs.mie.2018.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methanogenic archaea generate methane as a by-product of anaerobic respiration using CO2, C1 compounds (like methanol or methylated amines), or acetate as terminal electron acceptors. Methanogens are an untapped resource for biotechnological advances related to methane production as well as methane consumption. However, key biological features of these organisms remain poorly understood. One such feature is the enzyme methyl-coenzyme M reductase (referred to as MCR), which catalyzes the last step in the methanogenic pathway and results in methane formation. Gene essentiality has limited genetic analyses of MCR thus far. Therefore, studies of this important enzyme have been limited to biochemical and biophysical techniques that are especially laborious and often reliant on sophisticated instrumentation that is not commonly available. In this chapter, we outline our recently developed CRISPR-Cas9-based genome editing tools and describe how these tools have been used for the introduction of a tandem affinity purification tag at the chromosomal mcr locus in the model methanogen, Methanosarcina acetivorans C2A. We also report a protocol for rapid affinity purification of MCR from M. acetivorans C2A that will enable high-throughput studies of this enzyme in the future.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States
| | - William W Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States.
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27
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Wang B, Blaszczyk A, Knox HL, Zhou S, Blaesi EJ, Krebs C, Wang RX, Booker SJ. Stereochemical and Mechanistic Investigation of the Reaction Catalyzed by Fom3 from Streptomyces fradiae, a Cobalamin-Dependent Radical S-Adenosylmethionine Methylase. Biochemistry 2018; 57:4972-4984. [PMID: 30036047 PMCID: PMC6554712 DOI: 10.1021/acs.biochem.8b00693] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fom3, a cobalamin-dependent radical S-adenosylmethionine (SAM) methylase, has recently been shown to catalyze the methylation of carbon 2″ of cytidylyl-2-hydroxyethylphosphonate (HEP-CMP) to form cytidylyl-2-hydroxypropylphosphonate (HPP-CMP) during the biosynthesis of fosfomycin, a broad-spectrum antibiotic. It has been hypothesized that a 5'-deoxyadenosyl 5'-radical (5'-dA•) generated from the reductive cleavage of SAM abstracts a hydrogen atom from HEP-CMP to prime the substrate for addition of a methyl group from methylcobalamin (MeCbl); however, the mechanistic details of this reaction remain elusive. Moreover, it has been reported that Fom3 catalyzes the methylation of HEP-CMP to give a mixture of the ( S)-HPP and ( R)-HPP stereoisomers, which is rare for an enzyme-catalyzed reaction. Herein, we describe a detailed biochemical investigation of a Fom3 that is purified with 1 equiv of its cobalamin cofactor bound, which is almost exclusively in the form of MeCbl. Electron paramagnetic resonance and Mössbauer spectroscopies confirm that Fom3 contains one [4Fe-4S] cluster. Using deuterated enantiomers of HEP-CMP, we demonstrate that the 5'-dA• generated by Fom3 abstracts the C2″- pro-R hydrogen of HEP-CMP and that methyl addition takes place with inversion of configuration to yield solely ( S)-HPP-CMP. Fom3 also sluggishly converts cytidylyl-ethylphosphonate to the corresponding methylated product but more readily acts on cytidylyl-2-fluoroethylphosphonate, which exhibits a lower C2″ homolytic bond-dissociation energy. Our studies suggest a mechanism in which the substrate C2″ radical, generated upon hydrogen atom abstraction by the 5'-dA•, directly attacks MeCbl to transfer a methyl radical (CH3•) rather than a methyl cation (CH3+), directly forming cob(II)alamin in the process.
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Affiliation(s)
- Bo Wang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Anthony Blaszczyk
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Hayley L. Knox
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Shengbin Zhou
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Elizabeth J. Blaesi
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Roy X. Wang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Squire J. Booker
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Howard Hughes Medical Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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28
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McLaughlin MI, van der Donk WA. Stereospecific Radical-Mediated B 12-Dependent Methyl Transfer by the Fosfomycin Biosynthesis Enzyme Fom3. Biochemistry 2018; 57:4967-4971. [PMID: 29969250 PMCID: PMC6103835 DOI: 10.1021/acs.biochem.8b00616] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Fom3, the antepenultimate enzyme in the fosfomycin biosynthetic pathway in Streptomyces spp., is a class B cobalamin-dependent radical SAM methyltransferase that catalyzes methylation of (5'-cytidylyl)-2-hydroxyethylphosphonate (2-HEP-CMP) to form (5'-cytidylyl)-2-hydroxypropylphosphonate (2-HPP-CMP). Previously, the reaction of Fom3 with 2-HEP-CMP produced 2-HPP-CMP with mixed stereochemistry at C2. Mechanistic characterization has been challenging because of insoluble expression and poor cobalamin (B12) incorporation in Escherichia coli. Recently, soluble E. coli expression and incorporation of cobalamin into Fom3 were achieved by overexpression of the BtuCEDFB cobalamin uptake system. Herein, we use this new method to obtain Fom3 from Streptomyces wedmorensis. We show that the initiator 5'-deoxyadenosyl radical stereospecifically abstracts the pro- R hydrogen atom from the C2 position of 2-HEP-CMP and use the downstream enzymes FomD and Fom4 to demonstrate that our preparation of Fom3 produces only (2 S)-2-HPP-CMP. Additionally, we show that the added methyl group originates from SAM under multiple-turnover conditions, but the first turnover uses a methyl donor already present on the enzyme; furthermore, cobalamin isolated from Fom3 reaction mixtures contains methyl groups derived from SAM. These results are consistent with a model in which Fom3 catalyzes methyl transfer from SAM to cobalamin and the resulting methylcobalamin (MeCbl) is the ultimate methyl source for the reaction.
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Affiliation(s)
- Martin I. McLaughlin
- Department of Chemistry and Carl W. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department of Chemistry and Carl W. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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29
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Sato S, Miyanaga A, Kim SY, Kuzuyama T, Kudo F, Eguchi T. Biochemical and Structural Analysis of FomD That Catalyzes the Hydrolysis of Cytidylyl ( S)-2-Hydroxypropylphosphonate in Fosfomycin Biosynthesis. Biochemistry 2018; 57:4858-4866. [PMID: 30010320 DOI: 10.1021/acs.biochem.8b00690] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In fosfomycin biosynthesis, the hydrolysis of cytidylyl ( S)-2-hydroxypropylphosphonate [( S)-HPP-CMP] to afford ( S)-HPP is the only uncharacterized step. Because FomD is an uncharacterized protein with a DUF402 domain that is encoded in the fosfomycin biosynthetic gene cluster, FomD was hypothesized to be responsible for this reaction. In this study, FomD was found to hydrolyze ( S)-HPP-CMP to give ( S)-HPP and CMP efficiently in the presence of Mn2+ or Co2+. FomD also hydrolyzed cytidylyl 2-hydroxyethylphosphonate (HEP-CMP), which is a biosynthetic intermediate before C-methylation. The kcat/ KM value of FomD with ( S)-HPP-CMP was 10-fold greater than that with HEP-CMP, suggesting that FomD hydrolyzes ( S)-HPP-CMP rather than HEP-CMP in bacteria. The crystal structure of FomD showed that this protein adopts a barrel-like fold, which consists of a large twisted antiparallel β-sheet. This is a key structural feature of the DUF402 domain-containing proteins. Two metal cations are located between the FomD barrel and the two α-helices at the C-terminus and serve to presumably activate the phosphonate group of substrates for hydrolysis. Docking simulations with ( S)-HPP-CMP suggested that the methyl group at the C2 position of the HPP moiety is recognized by a hydrophobic interaction with Trp68. Further mutational analysis suggested that a conserved Tyr107 among the DUF402 domain family of proteins activates a water molecule to promote nucleophilic attack on the phosphorus atom of the phosphonate moiety. These findings provide mechanistic insights into the FomD reaction and lead to a complete understanding of the fosfomycin biosynthetic pathway in Streptomyces.
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Affiliation(s)
- Shusuke Sato
- Department of Chemistry , Tokyo Institute of Technology , 2-12-1 O-okayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - Akimasa Miyanaga
- Department of Chemistry , Tokyo Institute of Technology , 2-12-1 O-okayama , Meguro-ku, Tokyo 152-8551 , Japan
| | | | | | - Fumitaka Kudo
- Department of Chemistry , Tokyo Institute of Technology , 2-12-1 O-okayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - Tadashi Eguchi
- Department of Chemistry , Tokyo Institute of Technology , 2-12-1 O-okayama , Meguro-ku, Tokyo 152-8551 , Japan
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30
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Marques Netto CGC, Palmeira DJ, Brondani PB, Andrade LH. Enzymatic reactions involving the heteroatoms from organic substrates. AN ACAD BRAS CIENC 2018; 90:943-992. [PMID: 29742205 DOI: 10.1590/0001-3765201820170741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/01/2018] [Indexed: 11/22/2022] Open
Abstract
Several enzymatic reactions of heteroatom-containing compounds have been explored as unnatural substrates. Considerable advances related to the search for efficient enzymatic systems able to support a broader substrate scope with high catalytic performance are described in the literature. These reports include mainly native and mutated enzymes and whole cells biocatalysis. Herein, we describe the historical background along with the progress of biocatalyzed reactions involving the heteroatom(S, Se, B, P and Si) from hetero-organic substrates.
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Affiliation(s)
| | - Dayvson J Palmeira
- Departamento de Química Fundamental, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Patrícia B Brondani
- Departamento de Ciências Exatas e Educação, Universidade Federal de Santa Catarina, Blumenau, SC, Brazil
| | - Leandro H Andrade
- Departamento de Química Fundamental, Universidade de São Paulo, São Paulo, SP, Brazil
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31
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Discovery and Biosynthesis of the Antibiotic Bicyclomycin in Distantly Related Bacterial Classes. Appl Environ Microbiol 2018; 84:AEM.02828-17. [PMID: 29500259 PMCID: PMC5930311 DOI: 10.1128/aem.02828-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/21/2018] [Indexed: 01/23/2023] Open
Abstract
Bicyclomycin (BCM) is a clinically promising antibiotic that is biosynthesized by Streptomyces cinnamoneus DSM 41675. BCM is structurally characterized by a core cyclo(l-Ile-l-Leu) 2,5-diketopiperazine (DKP) that is extensively oxidized. Here, we identify the BCM biosynthetic gene cluster, which shows that the core of BCM is biosynthesized by a cyclodipeptide synthase, and the oxidative modifications are introduced by five 2-oxoglutarate-dependent dioxygenases and one cytochrome P450 monooxygenase. The discovery of the gene cluster enabled the identification of BCM pathways encoded by the genomes of hundreds of Pseudomonas aeruginosa isolates distributed globally, and heterologous expression of the pathway from P. aeruginosa SCV20265 demonstrated that the product is chemically identical to BCM produced by S. cinnamoneus. Overall, putative BCM gene clusters have been found in at least seven genera spanning Actinobacteria and Proteobacteria (Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria). This represents a rare example of horizontal gene transfer of an intact biosynthetic gene cluster across such distantly related bacteria, and we show that these gene clusters are almost always associated with mobile genetic elements. IMPORTANCE Bicyclomycin is the only natural product antibiotic that selectively inhibits the transcription termination factor Rho. This mechanism of action, combined with its proven biological safety and its activity against clinically relevant Gram-negative bacterial pathogens, makes it a very promising antibiotic candidate. Here, we report the identification of the bicyclomycin biosynthetic gene cluster in the known bicyclomycin-producing organism Streptomyces cinnamoneus, which will enable the engineered production of new bicyclomycin derivatives. The identification of this gene cluster also led to the discovery of hundreds of bicyclomycin pathways encoded in highly diverse bacteria, including in the opportunistic pathogen Pseudomonas aeruginosa. This wide distribution of a complex biosynthetic pathway is very unusual and provides an insight into how a pathway for an antibiotic can be transferred between diverse bacteria.
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32
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Nayak DD, Mahanta N, Mitchell DA, Metcalf WW. Post-translational thioamidation of methyl-coenzyme M reductase, a key enzyme in methanogenic and methanotrophic Archaea. eLife 2017; 6. [PMID: 28880150 PMCID: PMC5589413 DOI: 10.7554/elife.29218] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/11/2017] [Indexed: 12/14/2022] Open
Abstract
Methyl-coenzyme M reductase (MCR), found in strictly anaerobic methanogenic and methanotrophic archaea, catalyzes the reversible production and consumption of the potent greenhouse gas methane. The α subunit of MCR (McrA) contains several unusual post-translational modifications, including a rare thioamidation of glycine. Based on the presumed function of homologous genes involved in the biosynthesis of thioviridamide, a thioamide-containing natural product, we hypothesized that the archaeal tfuA and ycaO genes would be responsible for post-translational installation of thioglycine into McrA. Mass spectrometric characterization of McrA from the methanogenic archaeon Methanosarcina acetivorans lacking tfuA and/or ycaO revealed the presence of glycine, rather than thioglycine, supporting this hypothesis. Phenotypic characterization of the ∆ycaO-tfuA mutant revealed a severe growth rate defect on substrates with low free energy yields and at elevated temperatures (39°C - 45°C). Our analyses support a role for thioglycine in stabilizing the protein secondary structure near the active site.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States
| | - Nilkamal Mahanta
- Department of Chemistry, University of Illinois, Urbana, United States
| | - Douglas A Mitchell
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States.,Department of Chemistry, University of Illinois, Urbana, United States.,Department of Microbiology, University of Illinois, Urbana, United States
| | - William W Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States.,Department of Microbiology, University of Illinois, Urbana, United States
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33
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Sato S, Kudo F, Kim SY, Kuzuyama T, Eguchi T. Methylcobalamin-Dependent Radical SAM C-Methyltransferase Fom3 Recognizes Cytidylyl-2-hydroxyethylphosphonate and Catalyzes the Nonstereoselective C-Methylation in Fosfomycin Biosynthesis. Biochemistry 2017; 56:3519-3522. [PMID: 28678474 DOI: 10.1021/acs.biochem.7b00472] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A methylcobalamin (MeCbl)-dependent radical S-adenosyl-l-methionine (SAM) methyltransferase Fom3 was found to catalyze the C-methylation of cytidylyl-2-hydroxyethylphosphonate (HEP-CMP) to give cytidylyl-2-hydroxypropylphosphonate (HPP-CMP), although it was originally proposed to catalyze the C-methylation of 2-hydroxyethylphosphonate to give 2-hydroxypropylphosphonate in the biosynthesis of a unique C-P bond containing antibiotic fosfomycin in Streptomyces. Unexpectedly, the Fom3 reaction product from HEP-CMP was almost a 1:1 diastereomeric mixture of HPP-CMP, indicating that the C-methylation is not stereoselective. Presumably, only the CMP moiety of HEP-CMP is critical for substrate recognition; on the other hand, the enzyme does not fix the 2-hydroxy group of the substrate and either of the prochiral hydrogen atoms at the C2 position can be abstracted by the 5'-deoxyadenosyl radical generated from SAM to form the substrate radical intermediates, which react with MeCbl to afford the corresponding products. This strict substrate recognition mechanism with no stereoselectivity of a MeCbl-dependent radical SAM methyltransferase is remarkable in natural product biosynthetic chemistry, because such a hidden clue for selective substrate recognition is likely to be found in the other biosynthetic pathways.
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Affiliation(s)
- Shusuke Sato
- Department of Chemistry, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Seung-Young Kim
- Biotechnology Research Center, The University of Tokyo , 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tomohisa Kuzuyama
- Biotechnology Research Center, The University of Tokyo , 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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34
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Abstract
Oxidative cyclizations are important transformations that occur widely during natural product biosynthesis. The transformations from acyclic precursors to cyclized products can afford morphed scaffolds, structural rigidity, and biological activities. Some of the most dramatic structural alterations in natural product biosynthesis occur through oxidative cyclization. In this Review, we examine the different strategies used by nature to create new intra(inter)molecular bonds via redox chemistry. This Review will cover both oxidation- and reduction-enabled cyclization mechanisms, with an emphasis on the former. Radical cyclizations catalyzed by P450, nonheme iron, α-KG-dependent oxygenases, and radical SAM enzymes are discussed to illustrate the use of molecular oxygen and S-adenosylmethionine to forge new bonds at unactivated sites via one-electron manifolds. Nonradical cyclizations catalyzed by flavin-dependent monooxygenases and NAD(P)H-dependent reductases are covered to show the use of two-electron manifolds in initiating cyclization reactions. The oxidative installations of epoxides and halogens into acyclic scaffolds to drive subsequent cyclizations are separately discussed as examples of "disappearing" reactive handles. Last, oxidative rearrangement of rings systems, including contractions and expansions, will be covered.
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Affiliation(s)
- Man-Cheng Tang
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Yi Zou
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Christopher T. Walsh
- Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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35
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Nayak DD, Metcalf WW. Cas9-mediated genome editing in the methanogenic archaeon Methanosarcina acetivorans. Proc Natl Acad Sci U S A 2017; 114:2976-2981. [PMID: 28265068 PMCID: PMC5358397 DOI: 10.1073/pnas.1618596114] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although Cas9-mediated genome editing has proven to be a powerful genetic tool in eukaryotes, its application in Bacteria has been limited because of inefficient targeting or repair; and its application to Archaea has yet to be reported. Here we describe the development of a Cas9-mediated genome-editing tool that allows facile genetic manipulation of the slow-growing methanogenic archaeon Methanosarcina acetivorans Introduction of both insertions and deletions by homology-directed repair was remarkably efficient and precise, occurring at a frequency of approximately 20% relative to the transformation efficiency, with the desired mutation being found in essentially all transformants examined. Off-target activity was not observed. We also observed that multiple single-guide RNAs could be expressed in the same transcript, reducing the size of mutagenic plasmids and simultaneously simplifying their design. Cas9-mediated genome editing reduces the time needed to construct mutants by more than half (3 vs. 8 wk) and allows simultaneous construction of double mutants with high efficiency, exponentially decreasing the time needed for complex strain constructions. Furthermore, coexpression the nonhomologous end-joining (NHEJ) machinery from the closely related archaeon, Methanocella paludicola, allowed efficient Cas9-mediated genome editing without the need for a repair template. The NHEJ-dependent mutations included deletions ranging from 75 to 2.7 kb in length, most of which appear to have occurred at regions of naturally occurring microhomology. The combination of homology-directed repair-dependent and NHEJ-dependent genome-editing tools comprises a powerful genetic system that enables facile insertion and deletion of genes, rational modification of gene expression, and testing of gene essentiality.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - William W Metcalf
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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36
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Olivares P, Ulrich EC, Chekan JR, van der Donk WA, Nair SK. Characterization of Two Late-Stage Enzymes Involved in Fosfomycin Biosynthesis in Pseudomonads. ACS Chem Biol 2017; 12:456-463. [PMID: 27977135 DOI: 10.1021/acschembio.6b00939] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The broad-spectrum phosphonate antibiotic fosfomycin is currently in use for clinical treatment of infections caused by both Gram-positive and Gram-negative uropathogens. The antibiotic is biosynthesized by various streptomycetes, as well as by pseudomonads. Notably, the biosynthetic strategies used by the two genera share only two steps: the first step in which primary metabolite phosphoenolpyruvate (PEP) is converted to phosphonopyruvate (PnPy) and the terminal step in which 2-hydroxypropylphosphonate (2-HPP) is converted to fosfomycin. Otherwise, distinct enzymatic paths are employed. Here, we biochemically confirm the last two steps in the fosfomycin biosynthetic pathway of Pseudomonas syringae PB-5123, showing that Psf3 performs the reduction of 2-oxopropylphosphonate (2-OPP) to (S)-2-HPP, followed by the Psf4-catalyzed epoxidation of (S)-2-HPP to fosfomycin. Psf4 can also accept (R)-2-HPP as a substrate but instead performs an oxidation to make 2-OPP. We show that the combined activities of Psf3 and Psf4 can be used to convert racemic 2-HPP to fosfomycin in an enantioconvergent process. X-ray structures of each enzyme with bound substrates provide insights into the stereospecificity of each conversion. These studies shed light on the reaction mechanisms of the two terminal enzymes in a distinct pathway employed by pseudomonads for the production of a potent antimicrobial agent.
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Affiliation(s)
- Philip Olivares
- Department
of Biochemistry, ‡Department of Chemistry, §Carl R. Woese Institute for Genomic
Biology, ∥Howard Hughes Medical Institute, and ⊥Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Emily C. Ulrich
- Department
of Biochemistry, ‡Department of Chemistry, §Carl R. Woese Institute for Genomic
Biology, ∥Howard Hughes Medical Institute, and ⊥Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jonathan R. Chekan
- Department
of Biochemistry, ‡Department of Chemistry, §Carl R. Woese Institute for Genomic
Biology, ∥Howard Hughes Medical Institute, and ⊥Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Biochemistry, ‡Department of Chemistry, §Carl R. Woese Institute for Genomic
Biology, ∥Howard Hughes Medical Institute, and ⊥Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Satish K. Nair
- Department
of Biochemistry, ‡Department of Chemistry, §Carl R. Woese Institute for Genomic
Biology, ∥Howard Hughes Medical Institute, and ⊥Center for Biophysics and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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37
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Abstract
Fosfomycin, a natural product antibiotic, has been in use for >20 years in Spain, Germany, France, Japan, Brazil, and South Africa for urinary tract infections (UTIs) and other indications and was registered in the United States for the oral treatment of uncomplicated UTIs because of Enterococcus faecalis and Escherichia coli in 1996. It has a broad spectrum, is bactericidal, has very low toxicity, and acts as a time-dependent inhibitor of the MurA enzyme, which catalyzes the first committed step of peptidoglycan synthesis. Whereas resistance to fosfomycin arises rapidly in vitro through loss of active transport mechanisms, resistance is rarely seen during therapy of UTIs, seemingly because of the low fitness of the resistant organisms. Recently, interest has grown in the use of fosfomycin against multidrug-resistant (MDR) pathogens in other indications, prompting the advent of development in the United States of a parenteral formulation for use, initially, in complicated UTIs. Whereas resistance has not been problematic in the uncomplicated UTI setting, it remains to be seen whether resistance remains at bay with expansion to other indications.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, LLC, Springfield, New Jersey 07081
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38
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Freeman MF, Helf MJ, Bhushan A, Morinaka BI, Piel J. Seven enzymes create extraordinary molecular complexity in an uncultivated bacterium. Nat Chem 2016; 9:387-395. [DOI: 10.1038/nchem.2666] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 10/02/2016] [Indexed: 12/20/2022]
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39
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Abstract
Organophosphonic acids are unique as natural products in terms of stability and mimicry. The C-P bond that defines these compounds resists hydrolytic cleavage, while the phosphonyl group is a versatile mimic of transition-states, intermediates, and primary metabolites. This versatility may explain why a variety of organisms have extensively explored the use organophosphonic acids as bioactive secondary metabolites. Several of these compounds, such as fosfomycin and bialaphos, figure prominently in human health and agriculture. The enzyme reactions that create these molecules are an interesting mix of chemistry that has been adopted from primary metabolism as well as those with no chemical precedent. Additionally, the phosphonate moiety represents a source of inorganic phosphate to microorganisms that live in environments that lack this nutrient; thus, unusual enzyme reactions have also evolved to cleave the C-P bond. This review is a comprehensive summary of the occurrence and function of organophosphonic acids natural products along with the mechanisms of the enzymes that synthesize and catabolize these molecules.
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Affiliation(s)
- Geoff P Horsman
- Department of Chemistry and Biochemistry, Wilfrid Laurier University , Waterloo, Ontario N2L 3C5, Canada
| | - David L Zechel
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
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40
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Conserved biosynthetic pathways for phosalacine, bialaphos and newly discovered phosphonic acid natural products. J Antibiot (Tokyo) 2015; 69:15-25. [PMID: 26328935 PMCID: PMC4731264 DOI: 10.1038/ja.2015.77] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/14/2015] [Accepted: 06/15/2015] [Indexed: 12/03/2022]
Abstract
Natural products containing phosphonic or phosphinic acid functionalities often display potent biological activities with applications in medicine and agriculture. The herbicide phosphinothricin-tripeptide (PTT) was the first phosphinate natural product discovered, yet despite numerous studies, questions remain surrounding key transformations required for its biosynthesis. In particular, the enzymology required to convert phosphonoformate to carboxyphosphonoenolpyruvate and the mechanisms underlying phosphorus-methylation remain poorly understood. In addition, the model for NRPS assembly of the intact tripeptide product has undergone numerous revisions that have yet to be experimentally tested. To further investigate the biosynthesis of this unusual natural product, we completely sequenced the PTT biosynthetic locus from Streptomyces hygroscopicus and compared it to the orthologous cluster from Streptomyces viridochromogenes. We also sequenced and analysed the closely related phosalacine (PAL) biosynthetic locus from Kitasatospora phosalacinea. Using data drawn from the comparative analysis of the PTT and PAL pathways, we also evaluate three related recently discovered phosphonate biosynthetic loci from Streptomyces sviceus, Streptomyces sp. WM6386 and Frankia alni. Our observations address long-standing biosynthetic questions related to PTT and PAL production and suggest that additional members of this pharmacologically important class await discovery.
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Identification of the biosynthetic gene cluster for the herbicide phosphonothrixin in Saccharothrix sp. ST-888. J Antibiot (Tokyo) 2014; 68:357-9. [PMID: 25351949 DOI: 10.1038/ja.2014.149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ju KS, Doroghazi JR, Metcalf WW. Genomics-enabled discovery of phosphonate natural products and their biosynthetic pathways. J Ind Microbiol Biotechnol 2014; 41:345-56. [PMID: 24271089 PMCID: PMC3946943 DOI: 10.1007/s10295-013-1375-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 10/22/2013] [Indexed: 01/01/2023]
Abstract
Phosphonate natural products have proven to be a rich source of useful pharmaceutical, agricultural, and biotechnology products, whereas study of their biosynthetic pathways has revealed numerous intriguing enzymes that catalyze unprecedented biochemistry. Here we review the history of phosphonate natural product discovery, highlighting technological advances that have played a key role in the recent advances in their discovery. Central to these developments has been the application of genomics, which allowed discovery and development of a global phosphonate metabolic framework to guide research efforts. This framework suggests that the future of phosphonate natural products remains bright, with many new compounds and pathways yet to be discovered.
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Affiliation(s)
- Kou-San Ju
- Institute for Genomic Biology, University of Illinois, Urbana-Champaign, IL 61801
| | - James R. Doroghazi
- Institute for Genomic Biology, University of Illinois, Urbana-Champaign, IL 61801
| | - William W. Metcalf
- Institute for Genomic Biology, University of Illinois, Urbana-Champaign, IL 61801
- Department of Microbiology, University of Illinois, Urbana-Champaign, IL 61801
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Nikolaidis I, Favini-Stabile S, Dessen A. Resistance to antibiotics targeted to the bacterial cell wall. Protein Sci 2014; 23:243-59. [PMID: 24375653 DOI: 10.1002/pro.2414] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 12/21/2013] [Accepted: 12/23/2013] [Indexed: 11/10/2022]
Abstract
Peptidoglycan is the main component of the bacterial cell wall. It is a complex, three-dimensional mesh that surrounds the entire cell and is composed of strands of alternating glycan units crosslinked by short peptides. Its biosynthetic machinery has been, for the past five decades, a preferred target for the discovery of antibacterials. Synthesis of the peptidoglycan occurs sequentially within three cellular compartments (cytoplasm, membrane, and periplasm), and inhibitors of proteins that catalyze each stage have been identified, although not all are applicable for clinical use. A number of these antimicrobials, however, have been rendered inactive by resistance mechanisms. The employment of structural biology techniques has been instrumental in the understanding of such processes, as well as the development of strategies to overcome them. This review provides an overview of resistance mechanisms developed toward antibiotics that target bacterial cell wall precursors and its biosynthetic machinery. Strategies toward the development of novel inhibitors that could overcome resistance are also discussed.
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Affiliation(s)
- I Nikolaidis
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 6 rue Jules Horowitz, 38027, Grenoble, France; Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Grenoble, France; Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France; Bijvoet Center for Biomolecular Research, Department of Biochemistry of Membranes, Utrecht University, Utrecht, The Netherlands
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The global response regulator ExpA controls virulence gene expression through RsmA-mediated and RsmA-independent pathways in Pectobacterium wasabiae SCC3193. Appl Environ Microbiol 2014; 80:1972-84. [PMID: 24441162 DOI: 10.1128/aem.03829-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
ExpA (GacA) is a global response regulator that controls the expression of major virulence genes, such as those encoding plant cell wall-degrading enzymes (PCWDEs) in the model soft rot phytopathogen Pectobacterium wasabiae SCC3193. Several studies with pectobacteria as well as related phytopathogenic gammaproteobacteria, such as Dickeya and Pseudomonas, suggest that the control of virulence by ExpA and its homologues is executed partly by modulating the activity of RsmA, an RNA-binding posttranscriptional regulator. To elucidate the extent of the overlap between the ExpA and RsmA regulons in P. wasabiae, we characterized both regulons by microarray analysis. To do this, we compared the transcriptomes of the wild-type strain, an expA mutant, an rsmA mutant, and an expA rsmA double mutant. The microarray data for selected virulence-related genes were confirmed through quantitative reverse transcription (qRT-PCR). Subsequently, assays were performed to link the observed transcriptome differences to changes in bacterial phenotypes such as growth, motility, PCWDE production, and virulence in planta. An extensive overlap between the ExpA and RsmA regulons was observed, suggesting that a substantial portion of ExpA regulation appears to be mediated through RsmA. However, a number of genes involved in the electron transport chain and oligogalacturonide metabolism, among other processes, were identified as being regulated by ExpA independently of RsmA. These results suggest that ExpA may only partially impact fitness and virulence via RsmA.
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Diversity and abundance of phosphonate biosynthetic genes in nature. Proc Natl Acad Sci U S A 2013; 110:20759-64. [PMID: 24297932 DOI: 10.1073/pnas.1315107110] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphonates, molecules containing direct carbon-phosphorus bonds, compose a structurally diverse class of natural products with interesting and useful biological properties. Although their synthesis in protozoa was discovered more than 50 y ago, the extent and diversity of phosphonate production in nature remains poorly characterized. The rearrangement of phosphoenolpyruvate (PEP) to phosphonopyruvate, catalyzed by the enzyme PEP mutase (PepM), is shared by the vast majority of known phosphonate biosynthetic pathways. Thus, the pepM gene can be used as a molecular marker to examine the occurrence and abundance of phosphonate-producing organisms. Based on the presence of this gene, phosphonate biosynthesis is common in microbes, with ~5% of sequenced bacterial genomes and 7% of genome equivalents in metagenomic datasets carrying pepM homologs. Similarly, we detected the pepM gene in ~5% of random actinomycete isolates. The pepM-containing gene neighborhoods from 25 of these isolates were cloned, sequenced, and compared with those found in sequenced genomes. PEP mutase sequence conservation is strongly correlated with conservation of other nearby genes, suggesting that the diversity of phosphonate biosynthetic pathways can be predicted by examining PEP mutase diversity. We used this approach to estimate the range of phosphonate biosynthetic pathways in nature, revealing dozens of discrete groups in pepM amplicons from local soils, whereas hundreds were observed in metagenomic datasets. Collectively, our analyses show that phosphonate biosynthesis is both diverse and relatively common in nature, suggesting that the role of phosphonate molecules in the biosphere may be more important than is often recognized.
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Wang C, Chang WC, Guo Y, Huang H, Peck SC, Pandelia ME, Lin GM, Liu HW, Krebs C, Bollinger JM. Evidence that the fosfomycin-producing epoxidase, HppE, is a non-heme-iron peroxidase. Science 2013; 342:991-5. [PMID: 24114783 PMCID: PMC4160821 DOI: 10.1126/science.1240373] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The iron-dependent epoxidase HppE converts (S)-2-hydroxypropyl-1-phosphonate (S-HPP) to the antibiotic fosfomycin [(1R,2S)-epoxypropylphosphonate] in an unusual 1,3-dehydrogenation of a secondary alcohol to an epoxide. HppE has been classified as an oxidase, with proposed mechanisms differing primarily in the identity of the O2-derived iron complex that abstracts hydrogen (H•) from C1 of S-HPP to initiate epoxide ring closure. We show here that the preferred cosubstrate is actually H2O2 and that HppE therefore almost certainly uses an iron(IV)-oxo complex as the H• abstractor. Reaction with H2O2 is accelerated by bound substrate and produces fosfomycin catalytically with a stoichiometry of unity. The ability of catalase to suppress the HppE activity previously attributed to its direct utilization of O2 implies that reduction of O2 and utilization of the resultant H2O2 were actually operant.
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Affiliation(s)
- Chen Wang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
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Peck SC, van der Donk WA. Phosphonate biosynthesis and catabolism: a treasure trove of unusual enzymology. Curr Opin Chem Biol 2013; 17:580-8. [PMID: 23870698 DOI: 10.1016/j.cbpa.2013.06.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/15/2013] [Accepted: 06/17/2013] [Indexed: 11/25/2022]
Abstract
Natural product biosynthesis has proven a fertile ground for the discovery of novel chemistry. Herein we review the progress made in elucidating the biosynthetic pathways of phosphonate and phosphinate natural products such as the antibacterial compounds dehydrophos and fosfomycin, the herbicidal phosphinothricin-containing peptides, and the antimalarial compound FR-900098. In each case, investigation of the pathway has yielded unusual, and often unprecedented, biochemistry. Likewise, recent investigations have uncovered novel ways to cleave the CP bond to yield phosphate under phosphorus starvation conditions. These include the discovery of novel oxidative cleavage of the CP bond catalyzed by PhnY and PhnZ as well as phosphonohydrolases that liberate phosphate from phosphonoacetate. Perhaps the crown jewel of phosphonate catabolism has been the recent resolution of the longstanding problem of the C-P lyase responsible for reductively cleaving the CP bond of a number of different phosphonates to release phosphate. Taken together, the strides made on both metabolic and catabolic fronts illustrate an array of fascinating biochemistry.
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Affiliation(s)
- Spencer C Peck
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, USA
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Castañeda-García A, Blázquez J, Rodríguez-Rojas A. Molecular Mechanisms and Clinical Impact of Acquired and Intrinsic Fosfomycin Resistance. Antibiotics (Basel) 2013; 2:217-36. [PMID: 27029300 PMCID: PMC4790336 DOI: 10.3390/antibiotics2020217] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 11/16/2022] Open
Abstract
Bacterial infections caused by antibiotic-resistant isolates have become a major health problem in recent years, since they are very difficult to treat, leading to an increase in morbidity and mortality. Fosfomycin is a broad-spectrum bactericidal antibiotic that inhibits cell wall biosynthesis in both Gram-negative and Gram-positive bacteria. This antibiotic has a unique mechanism of action and inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme, MurA. Fosfomycin has been used successfully for the treatment of urinary tract infections for a long time, but the increased emergence of antibiotic resistance has made fosfomycin a suitable candidate for the treatment of infections caused by multidrug-resistant pathogens, especially in combination with other therapeutic partners. The acquisition of fosfomycin resistance could threaten the reintroduction of this antibiotic for the treatment of bacterial infection. Here, we analyse the mechanism of action and molecular mechanisms for the development of fosfomycin resistance, including the modification of the antibiotic target, reduced antibiotic uptake and antibiotic inactivation. In addition, we describe the role of each pathway in clinical isolates.
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Affiliation(s)
- Alfredo Castañeda-García
- Genome Damage and Stability Centre, University of Sussex, Falmer, Science Park Road, Brighton, East Sussex BN1 9RQ, UK.
| | - Jesús Blázquez
- Centro Nacional de Biotecnología (CSIC), Departamento de Biotecnología Microbiana, Calle Darwin 3, 28049 Madrid, Spain.
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Fullone MR, Paiardini A, Miele R, Marsango S, Gross DC, Omura S, Ros-Herrera E, Bonaccorsi di Patti MC, Laganà A, Pascarella S, Grgurina I. Insight into the structure-function relationship of the nonheme iron halogenases involved in the biosynthesis of 4-chlorothreonine - Thr3 fromStreptomycessp. OH-5093 and SyrB2 fromPseudomonas syringaepv.syringaeB301DR. FEBS J 2012; 279:4269-82. [DOI: 10.1111/febs.12017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 09/15/2012] [Accepted: 09/19/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Rosaria Fullone
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | - Rossella Miele
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | - Sara Marsango
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | - Dennis C. Gross
- Department of Plant Pathology & Microbiology; Texas A&M University; College Station; TX; USA
| | - Satoshi Omura
- Kitasato Institute for Life Sciences; Kitasato University; Tokyo; Japan
| | - Enric Ros-Herrera
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | | | - Aldo Laganà
- Department of Chemistry; Sapienza University of Rome; Italy
| | - Stefano Pascarella
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
| | - Ingeborg Grgurina
- Department of Biochemical Sciences ‘A. Rossi Fanelli’; Sapienza University of Rome; Italy
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