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Abstract
Covering: from 2000 up to the very early part of 2023S-Adenosyl-L-methionine (SAM) is a naturally occurring trialkyl sulfonium molecule that is typically associated with biological methyltransfer reactions. However, SAM is also known to donate methylene, aminocarboxypropyl, adenosyl and amino moieties during natural product biosynthetic reactions. The reaction scope is further expanded as SAM itself can be modified prior to the group transfer such that a SAM-derived carboxymethyl or aminopropyl moiety can also be transferred. Moreover, the sulfonium cation in SAM has itself been found to be critical for several other enzymatic transformations. Thus, while many SAM-dependent enzymes are characterized by a methyltransferase fold, not all of them are necessarily methyltransferases. Furthermore, other SAM-dependent enzymes do not possess such a structural feature suggesting diversification along different evolutionary lineages. Despite the biological versatility of SAM, it nevertheless parallels the chemistry of sulfonium compounds used in organic synthesis. The question thus becomes how enzymes catalyze distinct transformations via subtle differences in their active sites. This review summarizes recent advances in the discovery of novel SAM utilizing enzymes that rely on Lewis acid/base chemistry as opposed to radical mechanisms of catalysis. The examples are categorized based on the presence of a methyltransferase fold and the role played by SAM within the context of known sulfonium chemistry.
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Affiliation(s)
- Yu-Hsuan Lee
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Daan Ren
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Byungsun Jeon
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| | - Hung-Wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
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Mantas MJQ, Nunn PB, Ke Z, Codd GA, Barker D. Genomic insights into the biosynthesis and physiology of the cyanobacterial neurotoxin 2,4-diaminobutanoic acid (2,4-DAB). PHYTOCHEMISTRY 2021; 192:112953. [PMID: 34598041 DOI: 10.1016/j.phytochem.2021.112953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/09/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacteria are an ancient clade of photosynthetic prokaryotes, whose worldwide occurrence, especially in water, presents health hazards to humans and animals due to the production of a range of toxins (cyanotoxins). These include the sometimes co-occurring, non-encoded diaminoacid neurotoxins 2,4-diaminobutanoic acid (2,4-DAB) and its structural analogue β-N-methylaminoalanine (BMAA). Knowledge of the biosynthetic pathway for 2,4-DAB, and its role in cyanobacteria, is lacking. The aspartate 4-phosphate pathway is a known route of 2,4-DAB biosynthesis in other bacteria and in some plant species. Another pathway to 2,4-DAB has been described in Lathyrus species. Here, we use bioinformatics analyses to investigate hypotheses concerning 2,4-DAB biosynthesis in cyanobacteria. We assessed the presence or absence of each enzyme in candidate biosynthesis routes, the aspartate 4-phosphate pathway and a pathway to 2,4-DAB derived from S-adenosyl-L-methionine (SAM), in 130 cyanobacterial genomes using sequence alignment, profile hidden Markov models, substrate specificity/active site identification and the reconstruction of gene phylogenies. In the aspartate 4-phosphate pathway, for the 18 species encoding diaminobutanoate-2-oxo-glutarate transaminase, the co-localisation of genes encoding the transaminase with the downstream decarboxylase or ectoine synthase - often within hybrid non-ribosomal peptide synthetase (NRPS)-polyketide synthases (PKS) clusters, NRPS-independent siderophore (NIS) clusters and incomplete ectoine clusters - is compatible with the hypothesis that some cyanobacteria use the aspartate 4-phosphate pathway for 2,4-DAB production. Through this route, in cyanobacteria, 2,4-DAB may be functionally associated with environmental iron-scavenging, via the production of siderophores of the schizokinen/synechobactin type and of some polyamines. In the pathway to 2,4-DAB derived from SAM, eight cyanobacterial species encode homologs of SAM-dependent 3-amino-3-carboxypropyl transferases. Other enzymes in this pathway have not yet been purified or sequenced. Ultimately, the biosynthesis of 2,4-DAB appears to be either restricted to some cyanobacterial species, or there may be multiple and additional routes, and roles, for the synthesis of this neurotoxin.
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Affiliation(s)
- Maria José Q Mantas
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, The King's Buildings, Edinburgh, EH9 3FL, United Kingdom.
| | - Peter B Nunn
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.
| | - Ziying Ke
- School of Biological Sciences, Roger Land Building, The King's Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, United Kingdom; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom.
| | - Geoffrey A Codd
- School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom; School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, United Kingdom.
| | - Daniel Barker
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, The King's Buildings, Edinburgh, EH9 3FL, United Kingdom.
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Cui Z, Overbay J, Wang X, Liu X, Zhang Y, Bhardwaj M, Lemke A, Wiegmann D, Niro G, Thorson JS, Ducho C, Van Lanen SG. Pyridoxal-5'-phosphate-dependent alkyl transfer in nucleoside antibiotic biosynthesis. Nat Chem Biol 2020; 16:904-911. [PMID: 32483377 PMCID: PMC7377962 DOI: 10.1038/s41589-020-0548-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 04/10/2020] [Indexed: 11/09/2022]
Abstract
Several nucleoside antibiotics are structurally characterized by a 5′′-amino-5′′-deoxyribose (ADR) appended via a glycosidic bond to a high-carbon sugar nucleoside, (5′S,6′S)-5′-C-glycyluridine (GlyU). GlyU is further modified with an N-alkylamine linker, the biosynthetic origins of which have yet to be established. By using a combination of feeding experiments with isotopically labeled precursors and characterization of recombinant proteins from multiple pathways, the biosynthetic mechanism for N-alkylamine installation for ADR-GlyU-containing nucleoside antibiotics has been uncovered. The data reveal S-adenosyl-l-methionine (AdoMet) as the direct precursor of the N-alkylamine, but unlike conventional AdoMet- or decarboxylated AdoMet-dependent alkyltransferases, the reaction is catalyzed by a pyridoxal-5′-phophosate (PLP)-dependent aminobutyryltransferase (ABTase) using a stepwise γ-replacement mechanism that couples γ-elimination of AdoMet with aza-γ-addition onto the disaccharide alkyl acceptor. In addition to utilizing a conceptually different strategy for AdoMet-dependent alkylation, the newly discovered ABTases require a phosphorylated disaccharide alkyl acceptor, revealing a cryptic intermediate in the biosynthetic pathway.
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Affiliation(s)
- Zheng Cui
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Jonathan Overbay
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Xiachang Wang
- Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Xiaodong Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Yinan Zhang
- Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Minakshi Bhardwaj
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Anke Lemke
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Saarbrücken, Germany
| | - Daniel Wiegmann
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Saarbrücken, Germany
| | - Giuliana Niro
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Saarbrücken, Germany
| | - Jon S Thorson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Christian Ducho
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Saarbrücken, Germany
| | - Steven G Van Lanen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.
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Becker T, Pasteels J, Weigel C, Dahse HM, Voigt K, Boland W. A tale of four kingdoms – isoxazolin-5-one- and 3-nitropropanoic acid-derived natural products. Nat Prod Rep 2017; 34:343-360. [DOI: 10.1039/c6np00122j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The occurrence, structural diversity, (bio-)synthesis, properties and detoxification mechanisms of isoxazolinone- and 3-nitropropanoic acid-derived natural compounds are reviewed.
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Affiliation(s)
- Tobias Becker
- Department of Bioorganic Chemistry
- Max Planck Institute for Chemical Ecology
- Jena
- Germany
| | - Jacques Pasteels
- Department of Biology
- Université Libre de Bruxelles
- Brussels
- Belgium
| | - Christiane Weigel
- Leibniz Institute for Natural Product Research and Infection Biology
- Hans Knoell Institute
- Jena
- Germany
| | - Hans-Martin Dahse
- Leibniz Institute for Natural Product Research and Infection Biology
- Hans Knoell Institute
- Jena
- Germany
| | - Kerstin Voigt
- Leibniz Institute for Natural Product Research and Infection Biology
- Hans Knoell Institute
- Jena
- Germany
| | - Wilhelm Boland
- Department of Bioorganic Chemistry
- Max Planck Institute for Chemical Ecology
- Jena
- Germany
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Lin H. S-Adenosylmethionine-dependent alkylation reactions: when are radical reactions used? Bioorg Chem 2011; 39:161-70. [PMID: 21762947 DOI: 10.1016/j.bioorg.2011.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
Abstract
S-Adenosylmethionine (SAM) is a versatile small molecule used in many biological reactions. This review focuses on the mechanistic consideration of SAM-dependent methylation and 3-amino-3-carboxypropylation reactions. Special emphasis is given to methylation and 3-amino-3-carboxypropylation of carbon atoms, for which both nucleophilic mechanisms and radical mechanisms are used, depending on the specific enzymatic reactions. What is the logic behind Nature's choice of different reaction mechanisms? Here I aim to rationalize the choice of different reaction mechanisms in SAM-dependent alkylation reaction by analyzing a few enzymatic reactions in depth. These reactions include SAM-dependent cyclopropane fatty acid synthesis, DNA cytosine methylation, RNA adenosine C2 and C8 methylation, and 3-amino-3-carboxypropylation involved in diphthamide biosynthesis and wybutosine biosynthesis.
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Affiliation(s)
- Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, United States.
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Riepe M, Spencer PS, Lambein F, Ludolph AC, Allen CN. In vitro toxicological investigations of isoxazolinone amino acids of Lathyrus sativus. NATURAL TOXINS 1995; 3:58-64. [PMID: 7749584 DOI: 10.1002/nt.2620030111] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two non-protein amino acids of Lathyrus sativus, beta-(isoxazoline-5-on-2-yl)-alanine (BIA) and its higher homologue alpha-amino-gamma-(isoxazoline-5-on-2-yl)-alanine (ACI) were tested for excitotoxic potential. BIA (0.5-2.0 mM) but not ACI (2.0 mM) produced a concentration-dependent neurodegeneration in mouse cortical explants. The neuronal damage was prevented by the prior and simultaneous application of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), indicating that it was mediated by non-N-methyl-D-aspartate type receptors. BIA (0.5-2.0 mM) activated CNQX-sensitive currents which were significantly smaller than those activated by 3-N-oxalyl-L-2,3-diaminopropanoic acid (beta-ODAP) or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) in the majority of neurons. In a small number of cells, BIA (2 mM) produced currents which were similar in amplitude to those activated by beta-ODAP (50 microM). These results suggest that Lathyrus sativus plants engineered to block the synthesis of beta-ODAP may accumulate a neurotoxic precursor and therefore must be tested for the presence of both BIA and beta-ODAP.
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Affiliation(s)
- M Riepe
- Center for Research on Environmental and Occupational Toxicology, Oregon Health Sciences University, Portland 97201-3098, USA
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