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Skiba MA, Sikkema AP, Fiers WD, Gerwick WH, Sherman DH, Aldrich CC, Smith JL. Domain Organization and Active Site Architecture of a Polyketide Synthase C-methyltransferase. ACS Chem Biol 2016; 11:3319-3327. [PMID: 27723289 PMCID: PMC5224524 DOI: 10.1021/acschembio.6b00759] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyketide metabolites produced by modular type I polyketide synthases (PKS) acquire their chemical diversity through the variety of catalytic domains within modules of the pathway. Methyltransferases are among the least characterized of the catalytic domains common to PKS systems. We determined the domain boundaries and characterized the activity of a PKS C-methyltransferase (C-MT) from the curacin A biosynthetic pathway. The C-MT catalyzes S-adenosylmethionine-dependent methyl transfer to the α-position of β-ketoacyl substrates linked to acyl carrier protein (ACP) or a small-molecule analog but does not act on β-hydroxyacyl substrates or malonyl-ACP. Key catalytic residues conserved in both bacterial and fungal PKS C-MTs were identified in a 2 Å crystal structure and validated biochemically. Analysis of the structure and the sequences bordering the C-MT provides insight into the positioning of this domain within complete PKS modules.
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Fiers WD, Dodge GJ, Sherman DH, Smith JL, Aldrich CC. Vinylogous Dehydration by a Polyketide Dehydratase Domain in Curacin Biosynthesis. J Am Chem Soc 2016; 138:16024-16036. [PMID: 27960309 DOI: 10.1021/jacs.6b09748] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Polyketide synthase (PKS) enzymes continue to hold great promise as synthetic biology platforms for the production of novel therapeutic agents, biofuels, and commodity chemicals. Dehydratase (DH) catalytic domains play an important role during polyketide biosynthesis through the dehydration of the nascent polyketide intermediate to provide olefins. Our understanding of the detailed mechanistic and structural underpinning of DH domains that control substrate specificity and selectivity remains limited, thus hindering our efforts to rationally re-engineer PKSs. The curacin pathway houses a rare plurality of possible double bond permutations containing conjugated olefins as well as both cis- and trans-olefins, providing an unrivaled model system for polyketide dehydration. All four DH domains implicated in curacin biosynthesis were characterized in vitro using synthetic substrates, and activity was measured by LC-MS/MS analysis. These studies resulted in complete kinetic characterization of the all-trans-trienoate-forming CurK-DH, whose kcat of 72 s-1 is more than 3 orders of magnitude greater than that of any previously reported PKS DH domain. A novel stereospecific mechanism for diene formation involving a vinylogous enolate intermediate is proposed for the CurJ and CurH DHs on the basis of incubation studies with truncated substrates. A synthetic substrate was co-crystallized with a catalytically inactive Phe substitution in the His-Asp catalytic dyad of CurJ-DH to elucidate substrate-enzyme interactions. The resulting complex suggested the structural basis for dienoate formation and provided the first glimpse into the enzyme-substrate interactions essential for the formation of olefins in polyketide natural products. This examination of both canonical and non-canonical dehydration mechanisms reveals hidden catalytic activity inherent in some DH domains that may be leveraged for future applications in synthetic biology.
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DeMars MD, Sheng F, Park SR, Lowell AN, Podust LM, Sherman DH. Biochemical and Structural Characterization of MycCI, a Versatile P450 Biocatalyst from the Mycinamicin Biosynthetic Pathway. ACS Chem Biol 2016; 11:2642-54. [PMID: 27420774 PMCID: PMC5026600 DOI: 10.1021/acschembio.6b00479] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome P450 monooxygenases (P450s) are some of nature's most ubiquitous and versatile enzymes for performing oxidative metabolic transformations. Their unmatched ability to selectively functionalize inert C-H bonds has led to their increasing employment in academic and industrial settings for the production of fine and commodity chemicals. Many of the most interesting and potentially biocatalytically useful P450s come from microorganisms, where they catalyze key tailoring reactions in natural product biosynthetic pathways. While most of these enzymes act on structurally complex pathway intermediates with high selectivity, they often exhibit narrow substrate scope, thus limiting their broader application. In the present study, we investigated the reactivity of the P450 MycCI from the mycinamicin biosynthetic pathway toward a variety of macrocyclic compounds and discovered that the enzyme exhibits appreciable activity on several 16-membered ring macrolactones independent of their glycosylation state. These results were corroborated by performing equilibrium substrate binding experiments, steady-state kinetics studies, and X-ray crystallographic analysis of MycCI bound to its native substrate mycinamicin VIII. We also characterized TylHI, a homologous P450 from the tylosin pathway, and showed that its substrate scope is severely restricted compared to MycCI. Thus, the ability of the latter to hydroxylate both macrocyclic aglycones and macrolides sets it apart from related biosynthetic P450s and highlights its potential for developing novel P450 biocatalysts with broad substrate scope and high regioselectivity.
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Maloney FP, Gerwick L, Gerwick WH, Sherman DH, Smith JL. Anatomy of the β-branching enzyme of polyketide biosynthesis and its interaction with an acyl-ACP substrate. Proc Natl Acad Sci U S A 2016; 113:10316-21. [PMID: 27573844 PMCID: PMC5027445 DOI: 10.1073/pnas.1607210113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alkyl branching at the β position of a polyketide intermediate is an important variation on canonical polyketide natural product biosynthesis. The branching enzyme, 3-hydroxy-3-methylglutaryl synthase (HMGS), catalyzes the aldol addition of an acyl donor to a β-keto-polyketide intermediate acceptor. HMGS is highly selective for two specialized acyl carrier proteins (ACPs) that deliver the donor and acceptor substrates. The HMGS from the curacin A biosynthetic pathway (CurD) was examined to establish the basis for ACP selectivity. The donor ACP (CurB) had high affinity for the enzyme (Kd = 0.5 μM) and could not be substituted by the acceptor ACP. High-resolution crystal structures of HMGS alone and in complex with its donor ACP reveal a tight interaction that depends on exquisite surface shape and charge complementarity between the proteins. Selectivity is explained by HMGS binding to an unusual surface cleft on the donor ACP, in a manner that would exclude the acceptor ACP. Within the active site, HMGS discriminates between pre- and postreaction states of the donor ACP. The free phosphopantetheine (Ppant) cofactor of ACP occupies a conserved pocket that excludes the acetyl-Ppant substrate. In comparison with HMG-CoA (CoA) synthase, the homologous enzyme from primary metabolism, HMGS has several differences at the active site entrance, including a flexible-loop insertion, which may account for the specificity of one enzyme for substrates delivered by ACP and the other by CoA.
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Newmister SA, Gober CM, Romminger S, Yu F, Tripathi A, Parra LLL, Williams RM, Berlinck RG, Joullie MM, Sherman DH. OxaD: A Versatile Indolic Nitrone Synthase from the Marine-Derived Fungus Penicillium oxalicum F30. J Am Chem Soc 2016; 138:11176-84. [PMID: 27505044 PMCID: PMC5014723 DOI: 10.1021/jacs.6b04915] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Indole alkaloids are a diverse class of natural products known for their wide range of biological activities and complex chemical structures. Rarely observed in this class are indolic nitrones, such as avrainvillamide and waikialoid, which possess potent bioactivities. Herein the oxa gene cluster from the marine-derived fungus Penicillium oxalicum F30 is described along with the characterization of OxaD, a flavin-dependent oxidase that generates roquefortine L, a nitrone-bearing intermediate in the biosynthesis of oxaline. Nitrone functionality in roquefortine L was confirmed by spectroscopic methods and 1,3-dipolar cycloaddition with methyl acrylate. OxaD is a versatile biocatalyst that converts an array of semisynthetic roquefortine C derivatives bearing indoline systems to their respective nitrones. This work describes the first implementation of a nitrone synthase as a biocatalyst and establishes a novel platform for late-stage diversification of a range of complex natural products.
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Kleigrewe K, Gerwick L, Sherman DH, Gerwick WH. Unique marine derived cyanobacterial biosynthetic genes for chemical diversity. Nat Prod Rep 2016; 33:348-64. [PMID: 26758451 DOI: 10.1039/c5np00097a] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cyanobacteria are a prolific source of structurally unique and biologically active natural products that derive from intriguing biochemical pathways. Advancements in genome sequencing have accelerated the identification of unique modular biosynthetic gene clusters in cyanobacteria and reveal a wealth of unusual enzymatic reactions involved in their construction. This article examines several interesting mechanistic transformations involved in cyanobacterial secondary metabolite biosynthesis with a particular focus on marine derived modular polyketide synthases (PKS), nonribosomal peptide synthetases (NRPS) and combinations thereof to form hybrid natural products. Further, we focus on the cyanobacterial genus Moorea and the co-evolution of its enzyme cassettes that create metabolic diversity. Progress in the development of heterologous expression systems for cyanobacterial gene clusters along with chemoenzymatic synthesis makes it possible to create new analogs. Additionally, phylum-wide genome sequencing projects have enhanced the discovery rate of new natural products and their distinctive enzymatic reactions. Summarizing, cyanobacterial biosynthetic gene clusters encode for a large toolbox of novel enzymes that catalyze unique chemical reactions, some of which may be useful in synthetic biology.
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Beck ZQ, Burr DA, Sherman DH. Characterization of the beta-methylaspartate-alpha-decarboxylase (CrpG) from the cryptophycin biosynthetic pathway. Chembiochem 2016; 8:1373-5. [PMID: 17600793 DOI: 10.1002/cbic.200700162] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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83
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Klas K, Tsukamoto S, Sherman DH, Williams RM. Natural Diels-Alderases: Elusive and Irresistable. J Org Chem 2016; 80:11672-85. [PMID: 26495876 DOI: 10.1021/acs.joc.5b01951] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eight examples of biosynthetic pathways wherein a natural enzyme has been identified and claimed to function as a catalyst for the [4 + 2] cycloaddition reaction, namely, Diels-Alderases, are briefly reviewed. These are discussed in the context of the mechanistic challenges associated with the technical difficulty of proving that the net formal [4 + 2] cycloaddition under study indeed proceeds through a synchronous mechanism and that the putative biosynthetic enzyme deploys the pericyclic transition state required for a Diels-Alder cycloaddition reaction.
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Bertin MJ, Vulpanovici A, Monroe EA, Korobeynikov A, Sherman DH, Gerwick L, Gerwick WH. The Phormidolide Biosynthetic Gene Cluster: A trans-AT PKS Pathway Encoding a Toxic Macrocyclic Polyketide. Chembiochem 2016; 17:164-73. [PMID: 26769357 PMCID: PMC4878910 DOI: 10.1002/cbic.201500467] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Indexed: 11/09/2022]
Abstract
Phormidolide is a polyketide produced by a cultured filamentous marine cyanobacterium and incorporates a 16-membered macrolactone. Its complex structure is recognizably derived from a polyketide synthase pathway, but possesses unique and intriguing structural features that prompted interest in investigating its biosynthetic origin. Stable isotope incorporation experiments confirmed the polyketide nature of this compound. We further characterized the phormidolide gene cluster (phm) through genome sequencing followed by bioinformatic analysis. Two discrete trans-type acyltransferase (trans-AT) ORFs along with KS-AT adaptor regions (ATd) within the polyketide synthase (PKS) megasynthases, suggest that the phormidolide gene cluster is a trans-AT PKS. Insights gained from analysis of the mode of acetate incorporation and ensuing keto reduction prompted our reevaluation of the stereochemistry of phormidolide hydroxy groups located along the linear polyketide chain.
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85
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Kagiyama I, Kato H, Nehira T, Frisvad JC, Sherman DH, Williams RM, Tsukamoto S. Taichunamides: Prenylated Indole Alkaloids from Aspergillus taichungensis (IBT 19404). Angew Chem Int Ed Engl 2015; 55:1128-32. [PMID: 26644336 DOI: 10.1002/anie.201509462] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Indexed: 11/11/2022]
Abstract
Seven new prenylated indole alkaloids, taichunamides A-G, were isolated from the fungus Aspergillus taichungensis (IBT 19404). Taichunamides A and B contained an azetidine and 4-pyridone units, respectively, and are likely biosynthesized from notoamide S via (+)-6-epi-stephacidin A. Taichunamides C and D contain endoperoxide and methylsulfonyl units, respectively. This fungus produced indole alkaloids containing an anti-bicyclo[2.2.2]diazaoctane core, whereas A. protuberus and A. amoenus produced congeners with a syn-bicyclo[2.2.2]diazaoctane core. Plausible biosynthetic pathways to access these cores within the three species likely arise from an intramolecular hetero Diels-Alder reaction.
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Kagiyama I, Kato H, Nehira T, Frisvad JC, Sherman DH, Williams RM, Tsukamoto S. Taichunamides: Prenylated Indole Alkaloids from Aspergillus taichungensis
(IBT 19404). Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201509462] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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87
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Li S, Lowell AN, Yu F, Raveh A, Newmister SA, Bair N, Schaub JM, Williams RM, Sherman DH. Hapalindole/Ambiguine Biogenesis Is Mediated by a Cope Rearrangement, C-C Bond-Forming Cascade. J Am Chem Soc 2015; 137:15366-9. [PMID: 26629885 DOI: 10.1021/jacs.5b10136] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hapalindoles are bioactive indole alkaloids with fascinating polycyclic ring systems whose biosynthetic assembly mechanism has remained unknown since their initial discovery in the 1980s. In this study, we describe the fam gene cluster from the cyanobacterium Fischerella ambigua UTEX 1903 encoding hapalindole and ambiguine biosynthesis along with the characterization of two aromatic prenyltransferases, FamD1 and FamD2, and a previously undescribed cyclase, FamC1. These studies demonstrate that FamD2 and FamC1 act in concert to form the tetracyclic core ring system of the hapalindoles from cis-indole isonitrile and geranyl pyrophosphate through a presumed biosynthetic Cope rearrangement and subsequent 6-exo-trig cyclization/electrophilic aromatic substitution reaction.
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Sidhu A, Miller JR, Tripathi A, Garshott DM, Brownell AL, Chiego DJ, Arevang C, Zeng Q, Jackson LC, Bechler SA, Callaghan MU, Yoo GH, Sethi S, Lin HS, Callaghan JH, Tamayo-Castillo G, Sherman DH, Kaufman RJ, Fribley AM. Borrelidin Induces the Unfolded Protein Response in Oral Cancer Cells and Chop-Dependent Apoptosis. ACS Med Chem Lett 2015; 6:1122-7. [PMID: 26617965 DOI: 10.1021/acsmedchemlett.5b00133] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 09/08/2015] [Indexed: 12/12/2022] Open
Abstract
Oral squamous cell carcinoma (OSCC) is the most common cancer affecting the oral cavity, and US clinics will register about 30,000 new patients in 2015. Current treatment modalities include chemotherapy, surgery, and radiotherapy, which often result in astonishing disfigurement. Cancers of the head and neck display enhanced levels of glucose-regulated proteins and translation initiation factors associated with endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). Previous work demonstrated that chemically enforced UPR could overwhelm these adaptive features and selectively kill malignant cells. The threonyl-tRNA synthetase (ThRS) inhibitor borrelidin and two congeners were discovered in a cell-based chemical genomic screen. Borrelidin increased XBP1 splicing and led to accumulation of phosphorylated eIF2α and UPR-associated genes, prior to death in panel of OSCC cells. Murine embryonic fibroblasts (MEFs) null for GCN2 and PERK were less able to accumulate UPR markers and were resistant to borrelidin. This study demonstrates that UPR induction is a feature of ThRS inhibition and adds to a growing body of literature suggesting ThRS inhibitors might selectively target cancer cells.
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Cheng KCC, Cao S, Raveh A, MacArthur R, Dranchak P, Chlipala G, Okoneski MT, Guha R, Eastman RT, Yuan J, Schultz PJ, Su XZ, Tamayo-Castillo G, Matainaho T, Clardy J, Sherman DH, Inglese J. Actinoramide A Identified as a Potent Antimalarial from Titration-Based Screening of Marine Natural Product Extracts. JOURNAL OF NATURAL PRODUCTS 2015; 78:2411-2422. [PMID: 26465675 PMCID: PMC4633019 DOI: 10.1021/acs.jnatprod.5b00489] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Methods to identify the bioactive diversity within natural product extracts (NPEs) continue to evolve. NPEs constitute complex mixtures of chemical substances varying in structure, composition, and abundance. NPEs can therefore be challenging to evaluate efficiently with high-throughput screening approaches designed to test pure substances. Here we facilitate the rapid identification and prioritization of antimalarial NPEs using a pharmacologically driven, quantitative high-throughput-screening (qHTS) paradigm. In qHTS each NPE is tested across a concentration range from which sigmoidal response, efficacy, and apparent EC50s can be used to rank order NPEs for subsequent organism reculture, extraction, and fractionation. Using an NPE library derived from diverse marine microorganisms we observed potent antimalarial activity from two Streptomyces sp. extracts identified from thousands tested using qHTS. Seven compounds were isolated from two phylogenetically related Streptomyces species: Streptomyces ballenaensis collected from Costa Rica and Streptomyces bangulaensis collected from Papua New Guinea. Among them we identified actinoramides A and B, belonging to the unusually elaborated nonproteinogenic amino-acid-containing tetrapeptide series of natural products. In addition, we characterized a series of new compounds, including an artifact, 25-epi-actinoramide A, and actinoramides D, E, and F, which are closely related biosynthetic congeners of the previously reported metabolites.
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90
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Schofield MM, Jain S, Porat D, Dick GJ, Sherman DH. Identification and analysis of the bacterial endosymbiont specialized for production of the chemotherapeutic natural product ET-743. Environ Microbiol 2015; 17:3964-75. [PMID: 26013440 PMCID: PMC4618771 DOI: 10.1111/1462-2920.12908] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/15/2015] [Accepted: 05/16/2015] [Indexed: 11/26/2022]
Abstract
Ecteinascidin 743 (ET-743, Yondelis) is a clinically approved chemotherapeutic natural product isolated from the Caribbean mangrove tunicate Ecteinascidia turbinata. Researchers have long suspected that a microorganism may be the true producer of the anticancer drug, but its genome has remained elusive due to our inability to culture the bacterium in the laboratory using standard techniques. Here, we sequenced and assembled the complete genome of the ET-743 producer, Candidatus Endoecteinascidia frumentensis, directly from metagenomic DNA isolated from the tunicate. Analysis of the ∼ 631 kb microbial genome revealed strong evidence of an endosymbiotic lifestyle and extreme genome reduction. Phylogenetic analysis suggested that the producer of the anti-cancer drug is taxonomically distinct from other sequenced microorganisms and could represent a new family of Gammaproteobacteria. The complete genome has also greatly expanded our understanding of ET-743 production and revealed new biosynthetic genes dispersed across more than 173 kb of the small genome. The gene cluster's architecture and its preservation demonstrate that the drug is likely essential to the interactions of the microorganism with its mangrove tunicate host. Taken together, these studies elucidate the lifestyle of a unique, and pharmaceutically important microorganism and highlight the wide diversity of bacteria capable of making potent natural products.
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Medema MH, Kottmann R, Yilmaz P, Cummings M, Biggins JB, Blin K, de Bruijn I, Chooi YH, Claesen J, Coates RC, Cruz-Morales P, Duddela S, Düsterhus S, Edwards DJ, Fewer DP, Garg N, Geiger C, Gomez-Escribano JP, Greule A, Hadjithomas M, Haines AS, Helfrich EJN, Hillwig ML, Ishida K, Jones AC, Jones CS, Jungmann K, Kegler C, Kim HU, Kötter P, Krug D, Masschelein J, Melnik AV, Mantovani SM, Monroe EA, Moore M, Moss N, Nützmann HW, Pan G, Pati A, Petras D, Reen FJ, Rosconi F, Rui Z, Tian Z, Tobias NJ, Tsunematsu Y, Wiemann P, Wyckoff E, Yan X, Yim G, Yu F, Xie Y, Aigle B, Apel AK, Balibar CJ, Balskus EP, Barona-Gómez F, Bechthold A, Bode HB, Borriss R, Brady SF, Brakhage AA, Caffrey P, Cheng YQ, Clardy J, Cox RJ, De Mot R, Donadio S, Donia MS, van der Donk WA, Dorrestein PC, Doyle S, Driessen AJM, Ehling-Schulz M, Entian KD, Fischbach MA, Gerwick L, Gerwick WH, Gross H, Gust B, Hertweck C, Höfte M, Jensen SE, Ju J, Katz L, Kaysser L, Klassen JL, Keller NP, Kormanec J, Kuipers OP, Kuzuyama T, Kyrpides NC, Kwon HJ, Lautru S, Lavigne R, Lee CY, Linquan B, Liu X, Liu W, Luzhetskyy A, Mahmud T, Mast Y, Méndez C, Metsä-Ketelä M, Micklefield J, Mitchell DA, Moore BS, Moreira LM, Müller R, Neilan BA, Nett M, Nielsen J, O'Gara F, Oikawa H, Osbourn A, Osburne MS, Ostash B, Payne SM, Pernodet JL, Petricek M, Piel J, Ploux O, Raaijmakers JM, Salas JA, Schmitt EK, Scott B, Seipke RF, Shen B, Sherman DH, Sivonen K, Smanski MJ, Sosio M, Stegmann E, Süssmuth RD, Tahlan K, Thomas CM, Tang Y, Truman AW, Viaud M, Walton JD, Walsh CT, Weber T, van Wezel GP, Wilkinson B, Willey JM, Wohlleben W, Wright GD, Ziemert N, Zhang C, Zotchev SB, Breitling R, Takano E, Glöckner FO. Minimum Information about a Biosynthetic Gene cluster. Nat Chem Biol 2015; 11:625-31. [PMID: 26284661 PMCID: PMC5714517 DOI: 10.1038/nchembio.1890] [Citation(s) in RCA: 553] [Impact Index Per Article: 61.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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92
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Shinde PB, Oh HS, Choi H, Rathwell K, Ban YH, Kim EJ, Yang I, Lee DG, Sherman DH, Kang HY, Yoon YJ. Chemoenzymatic Synthesis of Glycosylated Macrolactam Analogues of the Macrolide Antibiotic YC-17. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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93
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Cruz PG, Fribley AM, Miller JR, Larsen MJ, Schultz PJ, Jacob RT, Tamayo-Castillo G, Kaufman RJ, Sherman DH. Novel Lobophorins Inhibit Oral Cancer Cell Growth and Induce Atf4- and Chop-Dependent Cell Death in Murine Fibroblasts. ACS Med Chem Lett 2015; 6:877-81. [PMID: 26288688 DOI: 10.1021/acsmedchemlett.5b00127] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/06/2015] [Indexed: 12/15/2022] Open
Abstract
As part of the International Cooperative Biodiversity Groups (ICBG) Program, we were interested in identifying biologically active unfolded protein response (UPR) inducing compounds from marine microorganisms isolated from Costa Rican biota. With this aim in mind we have now generated more than 33,000 unique prefractionated natural product extracts from marine and terrestrial organisms that have been submitted to the Center of Chemical Genomics (CCG) at the University of Michigan for high throughput screening (HTS). An effective complementary cell-based assay to identify novel modulators of UPR signaling was used for screening extracts. Active fractions were iteratively subjected to reverse-phase HPLC chromatographic analysis, and together with lobophorin A, B, E, and F (1-4), three new lobophorin congeners, designated as CR1 (5), CR2 (6), and CR3 (7) were isolated. Herein, we report that secondary assays revealed that the new lobophorins induced UPR-associated gene expression, inhibited oral squamous cell carcinoma cell growth, and led to UPR-dependent cell death in murine embryonic fibroblast (MEF) cells.
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Chemler JA, Tripathi A, Hansen DA, O'Neil-Johnson M, Williams RB, Starks C, Park SR, Sherman DH. Evolution of Efficient Modular Polyketide Synthases by Homologous Recombination. J Am Chem Soc 2015; 137:10603-9. [PMID: 26230368 DOI: 10.1021/jacs.5b04842] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural scaffolds of many complex natural products are produced by multifunctional type I polyketide synthase (PKS) enzymes that operate as biosynthetic assembly lines. The modular nature of these mega-enzymes presents an opportunity to construct custom biocatalysts built in a lego-like fashion by inserting, deleting, or exchanging native or foreign domains to produce targeted variants of natural polyketides. However, previously engineered PKS enzymes are often impaired resulting in limited production compared to native systems. Here, we show a versatile method for generating and identifying functional chimeric PKS enzymes for synthesizing custom macrolactones and macrolides. PKS genes from the pikromycin and erythromycin pathways were hybridized in Saccharomyces cerevisiae to generate hybrid libraries. We used a 96-well plate format for plasmid purification, transformations, sequencing, protein expression, in vitro reactions and analysis of metabolite formation. Active chimeric enzymes were identified with new functionality. Streptomyces venezuelae strains that expressed these PKS chimeras were capable of producing engineered macrolactones. Furthermore, a macrolactone generated from selected PKS chimeras was fully functionalized into a novel macrolide analogue. This method permits the engineering of PKS pathways as modular building blocks for the production of new antibiotic-like molecules.
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Boudreau PD, Monroe EA, Mehrotra S, Desfor S, Korobeynikov A, Sherman DH, Murray TF, Gerwick L, Dorrestein PC, Gerwick WH. Expanding the Described Metabolome of the Marine Cyanobacterium Moorea producens JHB through Orthogonal Natural Products Workflows. PLoS One 2015; 10:e0133297. [PMID: 26222584 PMCID: PMC4519256 DOI: 10.1371/journal.pone.0133297] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/25/2015] [Indexed: 11/18/2022] Open
Abstract
Moorea producens JHB, a Jamaican strain of tropical filamentous marine cyanobacteria, has been extensively studied by traditional natural products techniques. These previous bioassay and structure guided isolations led to the discovery of two exciting classes of natural products, hectochlorin (1) and jamaicamides A (2) and B (3). In the current study, mass spectrometry-based 'molecular networking' was used to visualize the metabolome of Moorea producens JHB, and both guided and enhanced the isolation workflow, revealing additional metabolites in these compound classes. Further, we developed additional insight into the metabolic capabilities of this strain by genome sequencing analysis, which subsequently led to the isolation of a compound unrelated to the jamaicamide and hectochlorin families. Another approach involved stimulation of the biosynthesis of a minor jamaicamide metabolite by cultivation in modified media, and provided insights about the underlying biosynthetic machinery as well as preliminary structure-activity information within this structure class. This study demonstrated that these orthogonal approaches are complementary and enrich secondary metabolomic coverage even in an extensively studied bacterial strain.
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96
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Lowell AN, Santoro N, Swaney SM, McQuade TJ, Schultz PJ, Larsen MJ, Sherman DH. Microscale Adaptation of In Vitro Transcription/Translation for High-Throughput Screening of Natural Product Extract Libraries. Chem Biol Drug Des 2015; 86:1331-8. [PMID: 26147927 DOI: 10.1111/cbdd.12614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/05/2015] [Accepted: 06/19/2015] [Indexed: 01/10/2023]
Abstract
Novel antimicrobials that effectively inhibit bacterial growth are essential to fight the growing threat of antibiotic resistance. A promising target is the bacterial ribosome, a 2.5 MDa organelle susceptible to several biorthogonal modes of action used by different classes of antibiotics. To promote the discovery of unique inhibitors, we have miniaturized a coupled transcription/translation assay using E. coli and applied it to screen a natural product library of ~30 000 extracts. We significantly reduced the scale of the assay to 2 μL in a 1536-well plate format and decreased the effective concentration of costly reagents. The improved assay returned 1327 hits (4.6% hit rate) with %CV and Z' values of 8.5% and 0.74, respectively. This assay represents a significant advance in molecular screening, both in miniaturization and its application to a natural product extract library, and we intend to apply it to a broad array of pathogenic microbes in the search for novel anti-infective agents.
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97
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Kleigrewe K, Almaliti J, Tian IY, Kinnel RB, Korobeynikov A, Monroe EA, Duggan BM, Di Marzo V, Sherman DH, Dorrestein PC, Gerwick L, Gerwick WH. Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria. JOURNAL OF NATURAL PRODUCTS 2015; 78:1671-82. [PMID: 26149623 PMCID: PMC4681511 DOI: 10.1021/acs.jnatprod.5b00301] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columbamides, a new class of di- and trichlorinated acyl amides with cannabinomimetic activity. Three species of cultured marine cyanobacteria, Moorea producens 3L, Moorea producens JHB, and Moorea bouillonii PNG, were subjected to genome sequencing and analysis for their recognizable biosynthetic pathways, and this information was then compared with their respective metabolomes as detected by MS profiling. By genome analysis, a presumed regulatory domain was identified upstream of several previously described biosynthetic gene clusters in two of these cyanobacteria, M. producens 3L and M. producens JHB. A similar regulatory domain was identified in the M. bouillonii PNG genome, and a corresponding downstream biosynthetic gene cluster was located and carefully analyzed. Subsequently, MS-based molecular networking identified a series of candidate products, and these were isolated and their structures rigorously established. On the basis of their distinctive acyl amide structure, the most prevalent metabolite was evaluated for cannabinomimetic properties and found to be moderate affinity ligands for CB1.
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98
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Sherman DH, Tsukamoto S, Williams RM. ORGANIC SYNTHESIS. Comment on "Asymmetric syntheses of sceptrin and massadine and evidence for biosynthetic enantiodivergence". Science 2015; 349:149. [PMID: 26160938 DOI: 10.1126/science.aaa9349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/05/2015] [Indexed: 11/02/2022]
Abstract
Ma et al. (Reports, 10 October 2014, p. 219) report asymmetric syntheses of sceptrin and massadine and, through a stereochemical reassignment, claim to "uncover enantiodivergence as a new biosynthetic paradigm for natural products." We challenge and clarify this claim with relevant examples from the literature of this well-known phenomenon of enantiodivergent congener biosynthesis within the same producing organism.
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Narayan ARH, Jiménez-Osés G, Liu P, Negretti S, Zhao W, Gilbert MM, Ramabhadran RO, Yang YF, Furan LR, Li Z, Podust LM, Montgomery J, Houk KN, Sherman DH. Enzymatic hydroxylation of an unactivated methylene C-H bond guided by molecular dynamics simulations. Nat Chem 2015. [PMID: 26201742 DOI: 10.1038/nchem.2285] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hallmark of enzymes from secondary metabolic pathways is the pairing of powerful reactivity with exquisite site selectivity. The application of these biocatalytic tools in organic synthesis, however, remains under-utilized due to limitations in substrate scope and scalability. Here, we report how the reactivity of a monooxygenase (PikC) from the pikromycin pathway is modified through computationally guided protein and substrate engineering, and applied to the oxidation of unactivated methylene C-H bonds. Molecular dynamics and quantum mechanical calculations were used to develop a predictive model for substrate scope, site selectivity and stereoselectivity of PikC-mediated C-H oxidation. A suite of menthol derivatives was screened computationally and evaluated through in vitro reactions, where each substrate adhered to the predicted models for selectivity and conversion to product. This platform was also expanded beyond menthol-based substrates to the selective hydroxylation of a variety of substrate cores ranging from cyclic to fused bicyclic and bridged bicyclic compounds.
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100
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McDonnell K, Chemler JA, Marvin ML, Stern RH, Raskin L, Sherman DH, Gruber SB. Characterization of a Novel Human MUTYH Variant Causing Colonic Polyposis through Disruption of the Fe-S Cluster. J Clin Oncol 2015. [DOI: 10.1200/jco.2015.33.15_suppl.e12514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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