1
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Guo Q, Morinaka BI. Accessing and exploring the unusual chemistry by radical SAM-RiPP enzymes. Curr Opin Chem Biol 2024; 81:102483. [PMID: 38917731 DOI: 10.1016/j.cbpa.2024.102483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/02/2024] [Accepted: 06/02/2024] [Indexed: 06/27/2024]
Abstract
Radical SAM enzymes involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptides catalyze unusual transformations that lead to unique peptide scaffolds and building blocks. Several natural products from these pathways show encouraging antimicrobial activities and represent next-generation therapeutics for infectious diseases. These systems are uniquely configured to benefit from genome-mining approaches because minimal substrate and cognate modifying enzyme expression can reveal unique, chemically complex transformations that outperform late-stage chemical reactions. This report highlights the main strategies used to reveal these enzymatic transformations, which have relied mainly on genome mining using enzyme-first approaches. We describe the general biosynthetic components for rSAM enzymes and highlight emerging approaches that may broaden the discovery and study of rSAM-RiPP enzymes. The large number of uncharacterized rSAM proteins, coupled with their unpredictable transformations, will continue to be an essential and exciting resource for enzyme discovery.
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Affiliation(s)
- Qianqian Guo
- Department of Pharmacy and Pharmaceutical Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy and Pharmaceutical Sciences, Faculty of Science, National University of Singapore, Singapore.
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2
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Purushothaman M, Chang L, Zhong RJ, Morinaka BI. The Triceptide Maturase OscB Catalyzes Uniform Cyclophane Topology and Accepts Diverse Gly-Rich Precursor Peptides. ACS Chem Biol 2024; 19:1229-1236. [PMID: 38742762 DOI: 10.1021/acschembio.4c00087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Triceptides are a class of ribosomally synthesized and post-translationally modified peptides defined by an aromatic C(sp2) to Cβ(sp3) bond. The Gly-rich repeat family of triceptide maturases (TIGR04261) are paired with precursor peptides (TIGR04260) containing a Gly-rich core peptide. These maturases are prevalent in cyanobacteria and catalyze cyclophane formation on multiple Ω1-X2-X3 motifs (Ω1 = Trp and Phe) of the Gly-rich precursor peptide. The topology of the individual rings has not been completely elucidated, and the promiscuity of these enzymes is not known. In this study, we characterized all the cyclophane rings formed by the triceptide maturase OscB and show the ring topology is uniform with respect to the substitution at Trp-C7 and the atropisomerism (planar chirality). Additionally, the enzyme OscB demonstrated substrate promiscuity on Gly-rich precursors and can accommodate a diverse array of engineered sequences. These findings highlight the versatility and implications for using OscB as a biocatalyst for producing polycyclophane-containing peptides for biotechnological applications.
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Affiliation(s)
- Mugilarasi Purushothaman
- Department of Pharmacy and Pharmaceutical Sciences, National University of Singapore, 4 Science Dr 2, Singapore 117544
| | - Litao Chang
- Department of Pharmacy and Pharmaceutical Sciences, National University of Singapore, 4 Science Dr 2, Singapore 117544
| | - Ryan Jian Zhong
- Department of Pharmacy and Pharmaceutical Sciences, National University of Singapore, 4 Science Dr 2, Singapore 117544
| | - Brandon I Morinaka
- Department of Pharmacy and Pharmaceutical Sciences, National University of Singapore, 4 Science Dr 2, Singapore 117544
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3
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Cheek LE, Zhu W. Structural features and substrate engagement in peptide-modifying radical SAM enzymes. Arch Biochem Biophys 2024; 756:110012. [PMID: 38663796 DOI: 10.1016/j.abb.2024.110012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
In recent years, the biological significance of ribosomally synthesized, post-translationally modified peptides (RiPPs) and the intriguing chemistry catalyzed by their tailoring enzymes has garnered significant attention. A subgroup of bacterial radical S-adenosylmethionine (rSAM) enzymes can activate C-H bonds in peptides, which leads to the production of a diverse range of RiPPs. The remarkable ability of these enzymes to facilitate various chemical processes, to generate and harbor high-energy radical species, and to accommodate large substrates with a high degree of flexibility is truly intriguing. The wide substrate scope and diversity of the chemistry performed by rSAM enzymes raise one question: how does the protein environment facilitate these distinct chemical conversions while sharing a similar structural fold? In this review, we discuss recent advances in the field of RiPP-rSAM enzymes, with a particular emphasis on domain architectures and substrate engagements identified by biophysical and structural characterizations. We provide readers with a comparative analysis of six examples of RiPP-rSAM enzymes with experimentally characterized structures. Linking the structural elements and the nature of rSAM-catalyzed RiPP production will provide insight into the functional engineering of enzyme activity to harness their catalytic power in broader applications.
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Affiliation(s)
- Lilly E Cheek
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA
| | - Wen Zhu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
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4
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Richter D, Piel J. Novel types of RiPP-modifying enzymes. Curr Opin Chem Biol 2024; 80:102463. [PMID: 38729090 DOI: 10.1016/j.cbpa.2024.102463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 05/12/2024]
Abstract
Novel discoveries in natural product biosynthesis reveal hidden bioactive compounds and expand our knowledge in enzymology. Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a rapidly growing class of natural products featuring diverse non-canonical amino acids introduced by maturation enzymes as a class-defining characteristic. Underexplored RiPP sources, such as the human microbiome, the oceans, uncultured microorganisms, and plants are rich hunting grounds for novel enzymology. Unusual α- and β-amino acids, peptide cleavages, lipidations, diverse macrocyclizations, and other features expand the range of chemical groups that are installed in RiPPs by often promiscuous enzymes. This review highlights the search for novelty in RiPP enzymology in the past two years, with respect to the discovery of new biochemical modifications but also towards novel applications.
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Affiliation(s)
- Daniel Richter
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland
| | - Jörn Piel
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
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5
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Chen JY, van der Donk WA. Multinuclear non-heme iron dependent oxidative enzymes (MNIOs) involved in unusual peptide modifications. Curr Opin Chem Biol 2024; 80:102467. [PMID: 38772214 DOI: 10.1016/j.cbpa.2024.102467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/23/2024]
Abstract
Multinuclear non-heme iron dependent oxidative enzymes (MNIOs), formerly known as domain of unknown function 692 (DUF692), are involved in the post-translational modification of peptides during the biosynthesis of peptide-based natural products. These enzymes catalyze highly unusual and diverse chemical modifications. Several class-defining features of this large family (>14 000 members) are beginning to emerge. Structurally, the enzymes are characterized by a TIM-barrel fold and a set of conserved residues for a di- or tri-iron binding site. They use molecular oxygen to modify peptide substrates, often in a four-electron oxidation taking place at a cysteine residue. This review summarizes the current understanding of MNIOs. Four modifications are discussed in detail: oxazolone-thioamide formation, β-carbon excision, hydantoin-macrocycle formation, and 5-thiooxazole formation. Briefly discussed are two other reactions that do not take place on Cys residues.
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Affiliation(s)
- Jeff Y Chen
- Department of Chemistry, The Carl R. Woese Institute for Genomic Biology, The Howard Hughes Medical Institute at the University of Illinois at Urbana-Champaign, 1206 W Gregory Drive, Urbana, IL 61801, USA
| | - Wilfred A van der Donk
- Department of Chemistry, The Carl R. Woese Institute for Genomic Biology, The Howard Hughes Medical Institute at the University of Illinois at Urbana-Champaign, 1206 W Gregory Drive, Urbana, IL 61801, USA.
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6
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Woodard AM, Peccati F, Navo CD, Jiménez-Osés G, Mitchell DA. Darobactin Substrate Engineering and Computation Show Radical Stability Governs Ether versus C-C Bond Formation. J Am Chem Soc 2024; 146:14328-14340. [PMID: 38728535 PMCID: PMC11225102 DOI: 10.1021/jacs.4c03994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
The Gram-negative selective antibiotic darobactin A has attracted interest owing to its intriguing fused bicyclic structure and unique targeting of the outer membrane protein BamA. Darobactin, a ribosomally synthesized and post-translationally modified peptide (RiPP), is produced by a radical S-adenosyl methionine (rSAM)-dependent enzyme (DarE) and contains one ether and one C-C cross-link. Herein, we analyze the substrate tolerance of DarE and describe an underlying catalytic principle of the enzyme. These efforts produced 51 enzymatically modified darobactin variants, revealing that DarE can install the ether and C-C cross-links independently and in different locations on the substrate. Notable variants with fused bicyclic structures were characterized, including darobactin W3Y, with a non-Trp residue at the twice-modified central position, and darobactin K5F, which displays a fused diether ring pattern. While lacking antibiotic activity, quantum mechanical modeling of darobactins W3Y and K5F aided in the elucidation of the requisite features for high-affinity BamA engagement. We also provide experimental evidence for β-oxo modification, which adds support for a proposed DarE mechanism. Based on these results, ether and C-C cross-link formation was investigated computationally, and it was determined that more stable and longer-lived aromatic Cβ radicals correlated with ether formation. Further, molecular docking and transition state structures based on high-level quantum mechanical calculations support the different indole connectivity observed for ether (Trp-C7) and C-C (Trp-C6) cross-links. Finally, mutational analysis and protein structural predictions identified substrate residues that govern engagement to DarE. Our work informs on darobactin scaffold engineering and further unveils the underlying principles of rSAM catalysis.
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Affiliation(s)
- Austin M Woodard
- Department of Chemistry, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Francesca Peccati
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Claudio D Navo
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Douglas A Mitchell
- Department of Chemistry, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
- Department of Microbiology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
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7
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Phan CS, Morinaka BI. Bacterial cyclophane-containing RiPPs from radical SAM enzymes. Nat Prod Rep 2024; 41:708-720. [PMID: 38047390 DOI: 10.1039/d3np00030c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Covering: 2016 to 2023Ribosomally synthesized and posttranslationally modified peptides (RiPPs) continue to be a rich source of chemically diverse and bioactive peptide natural products. In recent years, cyclophane-containing RiPP natural products and their biosynthetic pathways have been more frequently encountered. This highlight will focus on bacterial monoaryl cyclophane-containing RiPPs. This class of RiPPs is produced by radical SAM/SPASM enzymes that form a crosslink between the aromatic ring and sidechain of two amino acid residues of the precursor peptide. Selected natural products from these pathways exhibit specific antibacterial activity against gram-negative pathogens. The approaches used to discover these pathways and products will be described and categorized as natural product-first or enzyme-first. The breadth of ring systems formed by the enzymes, enzyme mechanism, and recent reports of synthetic methods for constructing these ring systems will also be presented. Bacterial cyclophane-containing RiPPs and their biosynthetic enzymes represent an untapped source of scaffolds for drug discovery and tools for synthetic biology.
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Affiliation(s)
- Chin-Soon Phan
- Department of Pharmacy, National University of Singapore, 4 Science Dr 2, Singapore 117544, Singapore.
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, 4 Science Dr 2, Singapore 117544, Singapore.
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8
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Nguyen DT, Zhu L, Gray DL, Woods TJ, Padhi C, Flatt KM, Mitchell DA, van der Donk WA. Biosynthesis of Macrocyclic Peptides with C-Terminal β-Amino-α-keto Acid Groups by Three Different Metalloenzymes. ACS CENTRAL SCIENCE 2024; 10:1022-1032. [PMID: 38799663 PMCID: PMC11117315 DOI: 10.1021/acscentsci.4c00088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 05/29/2024]
Abstract
Advances in genome sequencing and bioinformatics methods have identified a myriad of biosynthetic gene clusters (BGCs) encoding uncharacterized molecules. By mining genomes for BGCs containing a prevalent peptide-binding domain used for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), we uncovered a new compound class involving modifications installed by a cytochrome P450, a multinuclear iron-dependent non-heme oxidative enzyme (MNIO, formerly DUF692), a cobalamin- and radical S-adenosyl-l-methionine-dependent enzyme (B12-rSAM), and a methyltransferase. All enzymes were functionally expressed in Burkholderia sp. FERM BP-3421. Structural characterization demonstrated that the P450 enzyme catalyzed the formation of a biaryl C-C cross-link between two Tyr residues with the B12-rSAM generating β-methyltyrosine. The MNIO transformed a C-terminal Asp residue into aminopyruvic acid, while the methyltransferase acted on the β-carbon of this α-keto acid. Exciton-coupled circular dichroism spectroscopy and microcrystal electron diffraction (MicroED) were used to elucidate the stereochemical configuration of the atropisomer formed upon biaryl cross-linking. To the best of our knowledge, the MNIO featured in this pathway is the first to modify a residue other than Cys. This study underscores the utility of genome mining to isolate new macrocyclic RiPPs biosynthesized via previously undiscovered enzyme chemistry.
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Affiliation(s)
- Dinh T. Nguyen
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Lingyang Zhu
- School
of Chemical Sciences NMR Laboratory, University
of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Danielle L. Gray
- School
of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials
Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Toby J. Woods
- School
of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials
Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Chandrashekhar Padhi
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kristen M. Flatt
- Materials
Research Laboratory, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Douglas A. Mitchell
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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9
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Byerly-Duke J, O'Brien EA, Wall BJ, VanVeller B. Thioimidates provide general access to thioamide, amidine, and imidazolone peptide-bond isosteres. Methods Enzymol 2024; 698:27-55. [PMID: 38886036 DOI: 10.1016/bs.mie.2024.04.012] [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: 06/20/2024]
Abstract
Thioamides, amidines, and heterocycles are three classes of modifications that can act as peptide-bond isosteres to alter the peptide backbone. Thioimidate protecting groups can address many of the problematic synthetic issues surrounding installation of these groups. Historically, amidines have received little attention in peptides due to limitations in methods to access them. The first robust and general procedure for the introduction of amidines into peptide backbones exploits the utility of thioimidate protecting groups as a means to side-step reactivity that ultimately renders existing methods unsuitable for the installation of amidines along the main-chain of peptides. Further, amidines formed on-resin can be reacted to form (4H)-imidazolone heteorcycles which have recently been shown to act as cis-amide isosteres. General methods for heterocyclic installation capable of geometrically restricting peptide conformation are also under-developed. This work is significant because it describes a generally applicable and divergent approach to access unexplored peptide designs and architectures.
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Affiliation(s)
- Jacob Byerly-Duke
- Department of Chemistry, Iowa State University, Ames, IA, United States
| | - Emily A O'Brien
- Department of Chemistry, Iowa State University, Ames, IA, United States
| | - Brendan J Wall
- Department of Chemistry, Iowa State University, Ames, IA, United States
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, IA, United States.
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10
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Phan CS, Chang L, Nguyen TQN, Suarez AFL, Ho XH, Chen H, Koh IYF, Morinaka BI. Substrate Promiscuity of the Triceptide Maturase XncB Leads to Incorporation of Various Amino Acids and Detection of Oxygenated Products. ACS Chem Biol 2024; 19:855-860. [PMID: 38452396 DOI: 10.1021/acschembio.3c00782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Triceptides are cyclophane-containing ribosomally synthesized and post-translationally modified peptides. The characteristic cross-links are formed between an aromatic ring to Cβ on three-residue Ω1X2X3 motifs (Ω1 = aromatic). Here, we explored the promiscuity of the XYE family triceptide maturase, XncB from Xenorhabdus nematophila DSM 3370. Single amino acid variants were coexpressed with XncB in vivo in Escherichia coli, and we show that a variety of amino acids can be incorporated into the Phe-Gly-Asn cyclophane. Aromatic amino acids at the X3 position were accepted by the enzyme but yielded hydroxylated, rather than the typical cyclophane, products. These studies show that oxygen can be inserted but diverges in the final product formed relative to daropeptide maturases. Finally, truncations of the leader peptide showed that it is necessary for complete modification by XncB.
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Affiliation(s)
- Chin-Soon Phan
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Litao Chang
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Thi Quynh Ngoc Nguyen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | | | - Xuen Huei Ho
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Huiyi Chen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Ivan Yu Fan Koh
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
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11
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Nguyen DT, Mitchell DA, van der Donk WA. Genome Mining for New Enzyme Chemistry. ACS Catal 2024; 14:4536-4553. [PMID: 38601780 PMCID: PMC11002830 DOI: 10.1021/acscatal.3c06322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 04/12/2024]
Abstract
A revolution in the field of biocatalysis has enabled scalable access to compounds of high societal values using enzymes. The construction of biocatalytic routes relies on the reservoir of available enzymatic transformations. A review of uncharacterized proteins predicted from genomic sequencing projects shows that a treasure trove of enzyme chemistry awaits to be uncovered. This Review highlights enzymatic transformations discovered through various genome mining methods and showcases their potential future applications in biocatalysis.
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Affiliation(s)
- Dinh T. Nguyen
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Douglas A. Mitchell
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Howard
Hughes Medical Institute at the University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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12
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Mydy LS, Hungerford J, Chigumba DN, Konwerski JR, Jantzi SC, Wang D, Smith JL, Kersten RD. An intramolecular macrocyclase in plant ribosomal peptide biosynthesis. Nat Chem Biol 2024; 20:530-540. [PMID: 38355722 PMCID: PMC11049724 DOI: 10.1038/s41589-024-01552-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
The biosynthetic dogma of ribosomally synthesized and posttranslationally modified peptides (RiPP) involves enzymatic intermolecular modification of core peptide motifs in precursor peptides. The plant-specific BURP-domain protein family, named after their four founding members, includes autocatalytic peptide cyclases involved in the biosynthesis of side-chain-macrocyclic plant RiPPs. Here we show that AhyBURP, a representative of the founding Unknown Seed Protein-type BURP-domain subfamily, catalyzes intramolecular macrocyclizations of its core peptide during the sequential biosynthesis of monocyclic lyciumin I via glycine-tryptophan crosslinking and bicyclic legumenin via glutamine-tyrosine crosslinking. X-ray crystallography of AhyBURP reveals the BURP-domain fold with two type II copper centers derived from a conserved stapled-disulfide and His motif. We show the macrocyclization of lyciumin-C(sp3)-N-bond formation followed by legumenin-C(sp3)-O-bond formation requires dioxygen and radical involvement based on enzyme assays in anoxic conditions and isotopic labeling. Our study expands enzymatic intramolecular modifications beyond catalytic moiety and chromophore biogenesis to RiPP biosynthesis.
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Affiliation(s)
- Lisa S Mydy
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA.
| | - Jordan Hungerford
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Desnor N Chigumba
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | | | - Sarah C Jantzi
- Plasma Chemistry Laboratory, Center for Applied Isotope Studies, University of Georgia, Athens, GA, USA
| | - Di Wang
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Janet L Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Roland D Kersten
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA.
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13
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Chioti VT, Clark KA, Ganley JG, Han EJ, Seyedsayamdost MR. N-Cα Bond Cleavage Catalyzed by a Multinuclear Iron Oxygenase from a Divergent Methanobactin-like RiPP Gene Cluster. J Am Chem Soc 2024; 146:7313-7323. [PMID: 38452252 PMCID: PMC11062405 DOI: 10.1021/jacs.3c11740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
DUF692 multinuclear iron oxygenases (MNIOs) are an emerging family of tailoring enzymes involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs). Three members, MbnB, TglH, and ChrH, have been characterized to date and shown to catalyze unusual and complex transformations. Using a co-occurrence-based bioinformatic search strategy, we recently generated a sequence similarity network of MNIO-RiPP operons that encode one or more MNIOs adjacent to a transporter. The network revealed >1000 unique gene clusters, evidence of an unexplored biosynthetic landscape. Herein, we assess an MNIO-RiPP cluster from this network that is encoded in Proteobacteria and Actinobacteria. The cluster, which we have termed mov (for methanobactin-like operon in Vibrio), encodes a 23-residue precursor peptide, two MNIOs, a RiPP recognition element, and a transporter. Using both in vivo and in vitro methods, we show that one MNIO, homologous to MbnB, installs an oxazolone-thioamide at a Thr-Cys dyad in the precursor. Subsequently, the second MNIO catalyzes N-Cα bond cleavage of the penultimate Asn to generate a C-terminally amidated peptide. This transformation expands the reaction scope of the enzyme family, marks the first example of an MNIO-catalyzed modification that does not involve Cys, and sets the stage for future exploration of other MNIO-RiPPs.
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Affiliation(s)
- Vasiliki T Chioti
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kenzie A Clark
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jack G Ganley
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Esther J Han
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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14
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Suarez AFL, Nguyen TQN, Chang L, Tooh YW, Yong RHS, Leow LC, Koh IYF, Chen H, Koh JWH, Selvanayagam A, Lim V, Tan YE, Agatha I, Winnerdy FR, Morinaka BI. Functional and Promiscuity Studies of Three-Residue Cyclophane Forming Enzymes Show Nonnative C-C Cross-Linked Products and Leader-Dependent Cyclization. ACS Chem Biol 2024; 19:774-783. [PMID: 38417140 DOI: 10.1021/acschembio.3c00795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
Enzymes catalyzing peptide macrocyclization are important biochemical tools in drug discovery. The three-residue cyclophane-forming enzymes (3-CyFEs) are an emerging family of post-translational modifying enzymes that catalyze the formation of three-residue peptide cyclophanes. In this report, we introduce three additional 3-CyFEs, including ChlB, WnsB, and FnnB, that catalyze cyclophane formation on Tyr, Trp, and Phe, respectively. To understand the promiscuity of these enzymes and those previously reported (MscB, HaaB, and YxdB), we tested single amino acid substitutions at the three-residue motif of modification (Ω1X2X3, Ω1 = aromatic). Collectively, we observe that substrate promiscuity is observed at the Ω1 and X2 positions, but a greater specificity is observed for the X3 residue. Two nonnative cyclophane products were characterized showing a Phe-C3 to Arg-Cβ and His-C2 to Pro-Cβ cross-links, respectively. We also tested the leader dependence of selected 3-CyFEs and show that a predicted helix region is important for cyclophane formation. These results demonstrate the biocatalytic potential of these maturases and allow rational design of substrates to obtain a diverse array of genetically encoded 3-residue cyclophanes.
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Affiliation(s)
| | - Thi Quynh Ngoc Nguyen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Litao Chang
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Yi Wei Tooh
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Rubin How Sheng Yong
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Li Chuan Leow
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Ivan Yu Fan Koh
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Huiyi Chen
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Jeffery Wei Heng Koh
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | | | - Vernon Lim
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Yi En Tan
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Irene Agatha
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Fernaldo R Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
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15
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Eslami SM, van der Donk WA. Proteases Involved in Leader Peptide Removal during RiPP Biosynthesis. ACS BIO & MED CHEM AU 2024; 4:20-36. [PMID: 38404746 PMCID: PMC10885120 DOI: 10.1021/acsbiomedchemau.3c00059] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 02/27/2024]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) have received much attention in recent years because of their promising bioactivities and the portability of their biosynthetic pathways. Heterologous expression studies of RiPP biosynthetic enzymes identified by genome mining often leave a leader peptide on the final product to prevent toxicity to the host and to allow the attachment of a genetically encoded affinity purification tag. Removal of the leader peptide to produce the mature natural product is then carried out in vitro with either a commercial protease or a protease that fulfills this task in the producing organism. This review covers the advances in characterizing these latter cognate proteases from bacterial RiPPs and their utility as sequence-dependent proteases. The strategies employed for leader peptide removal have been shown to be remarkably diverse. They include one-step removal by a single protease, two-step removal by two dedicated proteases, and endoproteinase activity followed by aminopeptidase activity by the same protease. Similarly, the localization of the proteolytic step varies from cytoplasmic cleavage to leader peptide removal during secretion to extracellular leader peptide removal. Finally, substrate recognition ranges from highly sequence specific with respect to the leader and/or modified core peptide to nonsequence specific mechanisms.
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Affiliation(s)
- Sara M. Eslami
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, 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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16
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Johnson BA, Clark KA, Bushin LB, Spolar CN, Seyedsayamdost MR. Expanding the Landscape of Noncanonical Amino Acids in RiPP Biosynthesis. J Am Chem Soc 2024; 146:3805-3815. [PMID: 38316431 DOI: 10.1021/jacs.3c10824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Advancements in DNA sequencing technologies and bioinformatics have enabled the discovery of new metabolic reactions from overlooked microbial species and metagenomic sequences. Using a bioinformatic co-occurrence strategy, we previously generated a network of ∼600 uncharacterized quorum-sensing-regulated biosynthetic gene clusters that code for ribosomally synthesized and post-translationally modified peptide (RiPP) natural products and are tailored by radical S-adenosylmethionine (RaS) enzymes in streptococci. The most complex of these is the GRC subfamily, named after a conserved motif in the precursor peptide and found exclusively in Streptococcus pneumoniae, the causative agent of bacterial pneumonia. In this study, using both in vivo and in vitro approaches, we have elucidated the modifications installed by the grc biosynthetic enzymes, including a ThiF-like adenylyltransferase/cyclase that generates a C-terminal Glu-to-Cys thiolactone macrocycle, and two RaS enzymes, which selectively epimerize the β-carbon of threonine and desaturate histidine to generate the first instances of l-allo-Thr and didehydrohistidine in RiPP biosynthesis. RaS-RiPPs that have been discovered thus far have stood out for their exotic macrocycles. The product of the grc cluster breaks this trend by generating two noncanonical residues rather than an unusual macrocycle in the peptide substrate. These modifications expand the landscape of nonproteinogenic amino acids in RiPP natural product biosynthesis and motivate downstream biocatalytic applications of the corresponding enzymes.
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Affiliation(s)
- Brooke A Johnson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kenzie A Clark
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Leah B Bushin
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Calvin N Spolar
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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17
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Li H, Ding W, Zhang Q. Discovery and engineering of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products. RSC Chem Biol 2024; 5:90-108. [PMID: 38333193 PMCID: PMC10849128 DOI: 10.1039/d3cb00172e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/17/2023] [Indexed: 02/10/2024] Open
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) represent a diverse superfamily of natural products with immense potential for drug development. This review provides a concise overview of the recent advances in the discovery of RiPP natural products, focusing on rational strategies such as bioactivity guided screening, enzyme or precursor-based genome mining, and biosynthetic engineering. The challenges associated with activating silent biosynthetic gene clusters and the development of elaborate catalytic systems are also discussed. The logical frameworks emerging from these research studies offer valuable insights into RiPP biosynthesis and engineering, paving the way for broader pharmaceutic applications of these peptide natural products.
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Affiliation(s)
- He Li
- Department of Chemistry, Fudan University Shanghai 200433 China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Qi Zhang
- Department of Chemistry, Fudan University Shanghai 200433 China
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18
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Nguyen DT, Zhu L, Gray DL, Woods TJ, Padhi C, Flatt KM, Mitchell DA, van der Donk WA. Biosynthesis of macrocyclic peptides with C-terminal β-amino-α-keto acid groups by three different metalloenzymes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.30.564719. [PMID: 37965205 PMCID: PMC10635010 DOI: 10.1101/2023.10.30.564719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Advances in genome sequencing and bioinformatics methods have identified a myriad of biosynthetic gene clusters (BGCs) encoding uncharacterized molecules. By mining genomes for BGCs containing a prevalent peptide-binding domain used for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), we uncovered a new class involving modifications installed by a cytochrome P450, a multi-nuclear iron-dependent non-heme oxidative enzyme (MNIO, formerly DUF692), a cobalamin- and radical S-adenosyl-L-methionine-dependent enzyme (B12-rSAM), and a methyltransferase. All enzymes encoded by the BGC were functionally expressed in Burkholderia sp. FERM BP-3421. Structural characterization with 2D-NMR and Marfey's method on the resulting RiPP demonstrated that the P450 enzyme catalyzed the formation of a biaryl C-C crosslink between two Tyr residues with the B12-rSAM generating β-methyltyrosine. The MNIO transformed a C-terminal Asp residue into aminopyruvic acid while the methyltransferase acted on the β-carbon of the α-keto acid. Exciton-coupled circular dichroism spectroscopy and microcrystal electron diffraction (MicroED) were used to elucidate the stereochemical configurations of the atropisomer that formed upon biaryl crosslinking. The conserved Cys residue in the precursor peptide was not modified as in all other characterized MNIO-containing BGCs; However, mutational analyses demonstrated that it was essential for the MNIO activity on the C-terminal Asp. To the best of our knowledge, the MNIO featured in this pathway is the first to modify a residue other than Cys. This study underscores the utility of genome mining to discover new macrocyclic RiPPs and that RiPPs remain a significant source of previously undiscovered enzyme chemistry.
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Affiliation(s)
- Dinh T. Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Lingyang Zhu
- School of Chemical Sciences NMR Laboratory, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Danielle L. Gray
- School of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials Laboratory, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Toby J. Woods
- School of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials Laboratory, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Chandrashekhar Padhi
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Kristen M. Flatt
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Wilfred A. van der Donk
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
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19
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Woodard AM, Peccati F, Navo CD, Jiménez-Osés G, Mitchell DA. Benzylic Radical Stabilization Permits Ether Formation During Darobactin Biosynthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569256. [PMID: 38076856 PMCID: PMC10705402 DOI: 10.1101/2023.11.29.569256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
The Gram-negative selective antibiotic darobactin A has attracted interest owing to its intriguing fused bicyclic structure and unique mode of action. Biosynthetic studies have revealed that darobactin is a ribosomally synthesized and post-translationally modified peptide (RiPP). During maturation, the darobactin precursor peptide (DarA) is modified by a radical S-adenosyl methionine (rSAM)-dependent enzyme (DarE) to contain ether and C-C crosslinks. In this work, we describe the enzymatic tolerance of DarE using a panel of DarA variants, revealing that DarE can install the ether and C-C crosslinks independently and in different locations on DarA. These efforts produced 57 darobactin variants, 50 of which were enzymatically modified. Several new variants with fused bicyclic structures were characterized, including darobactin W3Y, which replaces tryptophan with tyrosine at the twice-modified central position, and darobactin K5F, which displays a fused diether ring pattern. Three additional darobactin variants contained fused diether macrocycles, leading us to investigate the origin of ether versus C-C crosslink formation. Computational analyses found that more stable and long-lived Cβ radicals found on aromatic amino acids correlated with ether formation. Further, molecular docking and calculated transition state structures provide support for the different indole connectivity observed for ether (Trp-C7) and C-C (Trp-C6) crosslink formation. We also provide experimental evidence for a β-oxotryptophan modification, a proposed intermediate during ether crosslink formation. Finally, mutational analysis of the DarA leader region and protein structural predictions identified which residues were dispensable for processing and others that govern substrate engagement by DarE. Our work informs on darobactin scaffold engineering and sheds additional light on the underlying principles of rSAM catalysis.
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Affiliation(s)
- Austin M. Woodard
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Francesca Peccati
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Claudio D. Navo
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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20
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He BB, Liu J, Cheng Z, Liu R, Zhong Z, Gao Y, Liu H, Song ZM, Tian Y, Li YX. Bacterial Cytochrome P450 Catalyzed Post-translational Macrocyclization of Ribosomal Peptides. Angew Chem Int Ed Engl 2023; 62:e202311533. [PMID: 37767859 DOI: 10.1002/anie.202311533] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 09/29/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a fascinating group of natural products that exhibit diverse structural features and bioactivities. P450-catalyzed RiPPs stand out as a unique but underexplored family. Herein, we introduce a rule-based genome mining strategy that harnesses the intrinsic biosynthetic principles of RiPPs, including the co-occurrence and co-conservation of precursors and P450s and interactions between them, successfully facilitating the identification of diverse P450-catalyzed RiPPs. Intensive BGC characterization revealed four new P450s, KstB, ScnB, MciB, and SgrB, that can catalyze the formation of Trp-Trp-Tyr (one C-C and two C-N bonds), Tyr-Trp (C-C bond), Trp-Trp (C-N bond), and His-His (ether bond) crosslinks, respectively, within three or four residues. KstB, ScnB, and MciB could accept non-native precursors, suggesting they could be promising starting templates for bioengineering to construct macrocycles. Our study highlights the potential of P450s to expand the chemical diversity of strained macrocyclic peptides and the range of biocatalytic tools available for peptide macrocyclization.
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Affiliation(s)
- Bei-Bei He
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jing Liu
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zhuo Cheng
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Runze Liu
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zheng Zhong
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ying Gao
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Hongyan Liu
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zhi-Man Song
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Yongqi Tian
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Yong-Xin Li
- Department of Chemistry and The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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21
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Ma S, Xi W, Wang S, Chen H, Guo S, Mo T, Chen W, Deng Z, Chen F, Ding W, Zhang Q. Substrate-Controlled Catalysis in the Ether Cross-Link-Forming Radical SAM Enzymes. J Am Chem Soc 2023; 145:22945-22953. [PMID: 37769281 DOI: 10.1021/jacs.3c04355] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Darobactin is a heptapeptide antibiotic featuring an ether cross-link and a C-C cross-link, and both cross-links are installed by a radical S-adenosylmethionine (rSAM) enzyme DarE. How a single DarE enzyme affords the two chemically distinct cross-links remains largely obscure. Herein, by mapping the biosynthetic landscape for darobactin-like RiPP (daropeptide), we identified and characterized two novel daropeptides that lack the C-C cross-link present in darobactin and instead are solely composed of ether cross-links. Phylogenetic and mutagenesis analyses reveal that the daropeptide maturases possess intrinsic multifunctionality, catalyzing not only the formation of ether cross-link but also C-C cross-linking and Ser oxidation. Intriguingly, the different chemical outcomes are controlled by the exact substrate motifs. Our work not only provides a roadmap for the discovery of new daropeptide natural products but also offers insights into the regulatory mechanisms that govern these remarkably versatile ether cross-link-forming rSAM enzymes.
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Affiliation(s)
- Suze Ma
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Wenhui Xi
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Shu Wang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Heng Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Sijia Guo
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tianlu Mo
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Wenxue Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fener Chen
- Department of Chemistry, Fudan University, Shanghai 200433, China
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China
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22
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Nam H, An JS, Lee J, Yun Y, Lee H, Park H, Jung Y, Oh KB, Oh DC, Kim S. Exploring the Diverse Landscape of Biaryl-Containing Peptides Generated by Cytochrome P450 Macrocyclases. J Am Chem Soc 2023; 145:22047-22057. [PMID: 37756205 DOI: 10.1021/jacs.3c07140] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Cytochrome P450 enzymes (P450s) catalyze diverse oxidative cross-coupling reactions between aromatic substrates in the natural product biosynthesis. Specifically, P450s install distinct biaryl macrocyclic linkages in three families of ribosomally synthesized and post-translationally modified peptides (RiPPs). However, the chemical diversity of biaryl-containing macrocyclic RiPPs remains largely unexplored. Here, we demonstrate that P450s have the capability to generate diverse biaryl linkages on RiPPs, collectively named "cyptides". Homology-based genome mining for P450 macrocyclases revealed 19 novel groups of homologous biosynthetic gene clusters (BGCs) with distinct aromatic residue patterns in the precursor peptides. Using the P450-modified precursor peptides heterologously coexpressed with corresponding P450s in Escherichia coli, we determined the NMR structures of three novel biaryl-containing peptides─the enzymatic products, roseovertin (1), rubrin (2), and lapparbin (3)─and confirmed the formation of three unprecedented or rare biaryl linkages: Trp C-7'-to-His N-τ in 1, Trp C-7'-to-Tyr C-6 in 2, and Tyr C-6-to-Trp N-1' in 3. Biochemical characterization indicated that certain P450s in these pathways have a relaxed substrate specificity. Overall, our studies suggest that P450 macrocyclases have evolved to create diverse biaryl linkages in RiPPs, promoting the exploration of a broader chemical space for biaryl-containing peptides encoded in bacterial genomes.
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23
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Cheng B, Huang J, Duan Y, Liu W. Association of Radical Chemistry with LanD Flavoprotein Activity for C-Terminal Macrocyclization of a Ribosomal Peptide by Formation of an Unsaturated Thioether Residue. Angew Chem Int Ed Engl 2023; 62:e202308733. [PMID: 37431841 DOI: 10.1002/anie.202308733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/12/2023]
Abstract
LanD flavoproteins catalyze oxidative decarboxylation of the C-terminal Cys residue of a peptide to produce an enethiol. This enethiol is highly reactive and can be coupled with an upstream dehydroamino acid through Michael addition to form S-[2-aminovinyl](3-methyl)cysteine, an unsaturated thioether residue known to be characteristic of an array of C-terminally macrocyclized, ribosomally synthesized and posttranslationally modified peptides (RiPPs). Based on a two-stage bioinformatics mining of posttranslational modifications (PTMs) related to C-terminal Cys processing, we report herein that LanD activity can couple with radical S-adenosylmethionine chemistry to provide a new unsaturated thioether residue, S-[2-aminovinyl]-3-carbamoylcysteine, by conjugating the resultant enethiol with Cβ of the Asn residue in the C-terminal NxxC motif of a peptide for macrocyclization. This study furthers our understanding of the variety of PTMs involved in creating the structure diversity of macrocyclic RiPPs.
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Affiliation(s)
- Botao Cheng
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Jiwu Huang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Yuting Duan
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Wen Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
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24
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Fernandez-Cantos MV, Garcia-Morena D, Yi Y, Liang L, Gómez-Vázquez E, Kuipers OP. Bioinformatic mining for RiPP biosynthetic gene clusters in Bacteroidales reveals possible new subfamily architectures and novel natural products. Front Microbiol 2023; 14:1219272. [PMID: 37469430 PMCID: PMC10352776 DOI: 10.3389/fmicb.2023.1219272] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/16/2023] [Indexed: 07/21/2023] Open
Abstract
The Bacteroidales order, widely distributed among diverse human populations, constitutes a key component of the human microbiota. Members of this Gram-negative order have been shown to modulate the host immune system, play a fundamental role in the gut's microbial food webs, or be involved in pathogenesis. Bacteria inhabiting such a complex environment as the human microbiome are expected to display social behaviors and, hence, possess factors that mediate cooperative and competitive interactions. Different types of molecules can mediate interference competition, including non-ribosomal peptides (NRPs), polyketides, and bacteriocins. The present study investigates the potential of Bacteroidales bacteria to biosynthesize class I bacteriocins, which are ribosomally synthesized and post-translationally modified peptides (RiPPs). For this purpose, 1,136 genome-sequenced strains from this order were mined using BAGEL4. A total of 1,340 areas of interest (AOIs) were detected. The most commonly identified enzymes involved in RiPP biosynthesis were radical S-adenosylmethionine (rSAM), either alone or in combination with other biosynthetic enzymes such as YcaO. A more comprehensive analysis of a subset of 9 biosynthetic gene clusters (BGCs) revealed a consistent association in Bacteroidales BGCs between peptidase-containing ATP-binding transporters (PCATs) and precursor peptides with GG-motifs. This finding suggests a possibly shared mechanism for leader peptide cleavage and transport of mature products. Notably, human metagenomic studies showed a high prevalence and abundance of the RiPP BGCs from Phocaeicola vulgatus and Porphyromonas gulae. The mature product of P. gulae BGC is hypothesized to display γ-thioether linkages and a C-terminal backbone amidine, a potential new combination of post-translational modifications (PTM). All these findings highlight the RiPP biosynthetic potential of Bacteroidales bacteria, as a rich source of novel peptide structures of possible relevance in the human microbiome context.
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Affiliation(s)
- Maria Victoria Fernandez-Cantos
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Diego Garcia-Morena
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Yunhai Yi
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | | | - Emilio Gómez-Vázquez
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Oscar P. Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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25
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Precord T, Ramesh S, Dommaraju SR, Harris LA, Kille BL, Mitchell DA. Catalytic Site Proximity Profiling for Functional Unification of Sequence-Diverse Radical S-Adenosylmethionine Enzymes. ACS BIO & MED CHEM AU 2023; 3:240-251. [PMID: 37363077 PMCID: PMC10288494 DOI: 10.1021/acsbiomedchemau.2c00085] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/28/2023]
Abstract
The radical S-adenosylmethionine (rSAM) superfamily has become a wellspring for discovering new enzyme chemistry, especially regarding ribosomally synthesized and post-translationally modified peptides (RiPPs). Here, we report a compendium of nearly 15,000 rSAM proteins with high-confidence involvement in RiPP biosynthesis. While recent bioinformatics advances have unveiled the broad sequence space covered by rSAM proteins, the significant challenge of functional annotation remains unsolved. Through a combination of sequence analysis and protein structural predictions, we identified a set of catalytic site proximity residues with functional predictive power, especially among the diverse rSAM proteins that form sulfur-to-α carbon thioether (sactionine) linkages. As a case study, we report that an rSAM protein from Streptomyces sparsogenes (StsB) shares higher full-length similarity with MftC (mycofactocin biosynthesis) than any other characterized enzyme. However, a comparative analysis of StsB to known rSAM proteins using "catalytic site proximity" predicted that StsB would be distinct from MftC and instead form sactionine bonds. The prediction was confirmed by mass spectrometry, targeted mutagenesis, and chemical degradation. We further used "catalytic site proximity" analysis to identify six new sactipeptide groups undetectable by traditional genome-mining strategies. Additional catalytic site proximity profiling of cyclophane-forming rSAM proteins suggests that this approach will be more broadly applicable and enhance, if not outright correct, protein functional predictions based on traditional genomic enzymology principles.
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Affiliation(s)
- Timothy
W. Precord
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sangeetha Ramesh
- Department
of Microbiology, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shravan R. Dommaraju
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Lonnie A. Harris
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Bryce L. Kille
- Department
of Computer Science, Rice University, Houston, Texas 77005, United States
| | - Douglas A. Mitchell
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
- Department
of Microbiology, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
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26
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Ayikpoe R, Zhu L, Chen JY, Ting CP, van der Donk WA. Macrocyclization and Backbone Rearrangement During RiPP Biosynthesis by a SAM-Dependent Domain-of-Unknown-Function 692. ACS CENTRAL SCIENCE 2023; 9:1008-1018. [PMID: 37252350 PMCID: PMC10214503 DOI: 10.1021/acscentsci.3c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Indexed: 05/31/2023]
Abstract
The domain of unknown function 692 (DUF692) is an emerging family of post-translational modification enzymes involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products. Members of this family are multinuclear iron-containing enzymes, and only two members have been functionally characterized to date: MbnB and TglH. Here, we used bioinformatics to select another member of the DUF692 family, ChrH, that is encoded in the genomes of the Chryseobacterium genus along with a partner protein ChrI. We structurally characterized the ChrH reaction product and show that the enzyme complex catalyzes an unprecedented chemical transformation that results in the formation of a macrocycle, an imidazolidinedione heterocycle, two thioaminals, and a thiomethyl group. Based on isotopic labeling studies, we propose a mechanism for the four-electron oxidation and methylation of the substrate peptide. This work identifies the first SAM-dependent reaction catalyzed by a DUF692 enzyme complex, further expanding the repertoire of remarkable reactions catalyzed by these enzymes. Based on the three currently characterized DUF692 family members, we suggest the family be called multinuclear non-heme iron dependent oxidative enzymes (MNIOs).
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Affiliation(s)
- Richard
S. Ayikpoe
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, 61801, Illinois, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
| | - Lingyang Zhu
- School
of Chemical Sciences NMR Laboratory, University
of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
| | - Jeff Y. Chen
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, 61801, Illinois, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
| | - Chi P. Ting
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, 61801, Illinois, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, University of Illinois at
Urbana−Champaign, Urbana, 61801, Illinois, United States
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
- Howard
Hughes Medical Institute at the University of Illinois at Urbana−Champaign, Urbana, 61801, Illinois, United States
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27
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Vagstad AL. Engineering ribosomally synthesized and posttranslationally modified peptides as new antibiotics. Curr Opin Biotechnol 2023; 80:102891. [PMID: 36702077 DOI: 10.1016/j.copbio.2023.102891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 11/22/2022] [Accepted: 12/19/2022] [Indexed: 01/25/2023]
Abstract
The rise of antimicrobial resistance is an urgent public health threat demanding the invention of new drugs to combat infections. Naturally sourced nonribosomal peptides (NRPs) have a long history as antimicrobial drugs. Through recent advances in genome mining and engineering technologies, their ribosomally synthesized and posttranslationally modified peptide (RiPP) counterparts are poised to further contribute to the arsenal of anti-infectives. As natural products from diverse organisms involved in interspecies competition, many RiPPs already possess antimicrobial activities that can be further optimized as drug candidates. Owing to the mutability of precursor protein genes that encode their core structures and the availability of diverse posttranslational modification (PTM) enzymes with broad substrate tolerances, RiPP systems are well suited to engineer complex peptides with desired functions.
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Affiliation(s)
- Anna L Vagstad
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland.
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28
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Lee H, Wu C, Desormeaux EK, Sarksian R, van der Donk WA. Improved production of class I lanthipeptides in Escherichia coli. Chem Sci 2023; 14:2537-2546. [PMID: 36908960 PMCID: PMC9993889 DOI: 10.1039/d2sc06597e] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
Lanthipeptides are ribosomally synthesised and post-translationally modified peptides containing lanthionine (Lan) and methyllanthionine (MeLan) residues that are formed by dehydration of Ser/Thr residues followed by conjugate addition of Cys to the resulting dehydroamino acids. Class I lanthipeptide dehydratases utilize glutamyl-tRNAGlu as a co-substrate to glutamylate Ser/Thr followed by glutamate elimination. Here we report a new system to heterologously express class I lanthipeptides in Escherichia coli through co-expression of the producing organism's glutamyl-tRNA synthetase (GluRS) and tRNAGlu pair in the vector pEVOL. In contrast to the results in the absence of the pEVOL system, we observed the production of fully-dehydrated peptides, including epilancin 15X, and peptides from the Bacteroidota Chryseobacterium and Runella. A second common obstacle to production of lanthipeptides in E. coli is the formation of glutathione adducts. LanC-like (LanCL) enzymes were previously reported to add glutathione to dehydroamino-acid-containing proteins in Eukarya. Herein, we demonstrate that the LanCL enzymes can remove GSH adducts from C-glutathionylated peptides with dl- or ll-lanthionine stereochemistry. These two advances will aid synthetic biology-driven genome mining efforts to discover new lanthipeptides.
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Affiliation(s)
- Hyunji Lee
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign 1206 W Gregory Drive Urbana Illinois 61801 USA
- College of Pharmacy, Kyungsung University Busan 48434 Republic of Korea
| | - Chunyu Wu
- Department of Biochemistry, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana Illinois 61801 USA
| | - Emily K Desormeaux
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana Illinois 61801 USA
| | - Raymond Sarksian
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana Illinois 61801 USA
| | - Wilfred A van der Donk
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign 1206 W Gregory Drive Urbana Illinois 61801 USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana Illinois 61801 USA
- Department of Chemistry, The Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign 600 South Mathews Avenue Urbana Illinois 61801 USA
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29
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Ayikpoe RS, Zhu L, Chen JY, Ting CP, van der Donk WA. A remarkable transformation catalyzed by a domain-of-unknown-function 692 during the biosynthesis of a new RiPP natural product. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.527370. [PMID: 36798408 PMCID: PMC9934569 DOI: 10.1101/2023.02.06.527370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The domain of unknown function 692 (DUF692) is an emerging family of posttranslational modification enzymes involved in the biosynthesis of ribosomally-synthesized and posttranslationally modified peptide (RiPP) natural products. Members of this family are multinuclear iron-containing enzymes and only two members have been functionally characterized to date: MbnB and TglH. Here, we used bioinformatics to select another member of the DUF692 family, ChrH, that is ubiquitously encoded in the genomes of the Chryseobacterium genus along with a partner protein ChrI. We structurally characterized the ChrH reaction product and show that the enzyme catalyzes an unprecedented chemical transformation that results in the formation of a macrocycle, an imidazolidinedione heterocycle, two thioaminals, and a thiomethylation. Based on isotopic labeling studies, we propose a mechanism for the four-electron oxidation and methylation of the substrate peptide. This work identifies the first SAM-dependent DUF692 enzyme, further expanding the repertoire of remarkable reactions catalyzed by these enzymes.
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Affiliation(s)
- Richard S. Ayikpoe
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Lingyang Zhu
- School of Chemical Sciences NMR Laboratory, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Jeff Y. Chen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Chi P. Ting
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
| | - Wilfred A. van der Donk
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
- Howard Hughes Medical Institute at the University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA
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30
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Phan CS, Morinaka BI. A Prevalent Group of Actinobacterial Radical SAM/SPASM Maturases Involved in Triceptide Biosynthesis. ACS Chem Biol 2022; 17:3284-3289. [PMID: 36454686 DOI: 10.1021/acschembio.2c00621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Triceptides are ribosomally synthesized and post-translationally modified peptides characterized by three-residue cyclophanes. The cyclophanes are installed by radical SAM/SPASM maturases referred to as 3-residue cyclophane forming enzymes (3-CyFEs) which catalyze C(sp2)-Cβ(sp3) bond formation on three residue motifs at the C-terminus of precursor peptides. Here, we bioinformatically map uncharacterized rSAM/SPASM enzymes, referred to as Actinobacterial multiple cyclophane maturases. The enzyme FwwB from Actinospira robinae was selected for in vivo functional studies in Escherichia coli, and was found to catalyze formation of multiple Phe- and Trp-derived 3-residue cyclophanes. FwwB was shown to accept a series of engineered substrates but showed specificity for the native 3-residue motif.
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Affiliation(s)
- Chin-Soon Phan
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
| | - Brandon I Morinaka
- Department of Pharmacy, National University of Singapore, Singapore 117544, Singapore
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31
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O’Brien EA, Sharma KK, Byerly-Duke J, Camacho LA, VanVeller B. A General Strategy to Install Amidine Functional Groups Along the Peptide Backbone. J Am Chem Soc 2022; 144:22397-22402. [PMID: 36469014 PMCID: PMC9886086 DOI: 10.1021/jacs.2c09085] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amidines are a structural surrogate for peptide bonds, yet have received considerably little attention in peptides due to limitations in existing methods to access them. The synthetic strategy developed in this study represents the first robust and general procedure for the introduction of amidines into the peptide backbone. We exploit and further develop the utility and efficiency of thioimidate protecting groups as a means to side-step reactivity that ultimately renders existing methods unsuitable for the installation of amidines along the main-chain of peptides. This work is significant because it describes a generally applicable path to access unexplored peptide designs and architectures for new therapeutics made possible by the unique properties of amidines.
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