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McCullough TM, Choudhary V, Akey DL, Skiba MA, Bernard SM, Kittendorf JD, Schmidt JJ, Sherman DH, Smith JL. Substrate Trapping in Polyketide Synthase Thioesterase Domains: Structural Basis for Macrolactone Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599880. [PMID: 38948807 PMCID: PMC11213023 DOI: 10.1101/2024.06.20.599880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Emerging antibiotic resistance requires continual improvement in the arsenal of antimicrobial drugs, especially the critical macrolide antibiotics. Formation of the macrolactone scaffold of these polyketide natural products is catalyzed by a modular polyketide synthase (PKS) thioesterase (TE). The TE accepts a linear polyketide substrate from the termina PKS acyl carrier protein to generate an acyl-enzyme adduct that is resolved by attack of a substrate hydroxyl group to form the macrolactone. Our limited mechanistic understanding of TE selectivity for a substrate nucleophile and/or water has hampered development of TEs as biocatalysts that accommodate a variety of natural and non-natural substrates. To understand how TEs direct the substrate nucleophile for macrolactone formation, acyl-enzyme intermediates were trapped as stable amides by substituting the natural serine OH with an amino group. Incorporation of the unnatural amino acid, 1,3-diaminopropionic acid (DAP), was tested with five PKS TEs. DAP-modified TEs (TE DAP ) from the pikromycin and erythromycin pathways were purified and tested with six full-length polyketide intermediates from three pathways. The erythromycin TE had permissive substrate selectivity, whereas the pikromycin TE was selective for its native hexaketide and heptaketide substrates. In a crystal structure of a native substrate trapped in pikromycin TE DAP , the linear heptaketide was curled in the active site with the nucleophilic hydroxyl group positioned 4 Å from the amide-enzyme linkage. The curled heptaketide displayed remarkable shape complementarity with the TE acyl cavity. The strikingly different shapes of acyl cavities in TEs of known structure, including those reported here for juvenimicin, tylosin and fluvirucin biosynthesis, provide new insights to facilitate TE engineering and optimization.
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2
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Jo WS, Curtis BJ, Rehan M, Adrover-Castellano ML, Sherman DH, Healy AR. N-to- S Acyl Transfer as an Enabling Strategy in Asymmetric and Chemoenzymatic Synthesis. JACS AU 2024; 4:2058-2066. [PMID: 38818054 PMCID: PMC11134368 DOI: 10.1021/jacsau.4c00257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 06/01/2024]
Abstract
The observation of thioester-mediated acyl transfer processes in nature has inspired the development of novel protein synthesis and functionalization methodologies. The chemoselective transfer of an acyl group from S-to-N is the basis of several powerful ligation strategies. In this work, we sought to apply the reverse process, the transfer of an acyl group from N-to-S, as a method to convert stable chiral amides into more reactive thioesters. To this end, we developed a novel cysteine-derived oxazolidinone that serves as both a chiral imide auxiliary and an acyl transfer agent. This auxiliary combines the desirable features of rigid chiral imides as templates for asymmetric transformations with the synthetic applicability of thioesters. We demonstrate that the auxiliary can be applied in a range of highly selective asymmetric transformations. Subsequent intramolecular N-to-S acyl transfer of the chiral product and in situ trapping of the resulting thioester provides access to diverse carboxylic acid derivatives under mild conditions. The oxazolidinone thioester products can also be isolated and used in Pd-mediated transformations to furnish highly valuable chiral scaffolds, such as noncanonical amino acids, cyclic ketones, tetrahydropyrones, and dihydroquinolinones. Finally, we demonstrate that the oxazolidinone thioesters can also serve as a surrogate for SNAC-thioesters, enabling their seamless use as non-native substrates in biocatalytic transformations.
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Affiliation(s)
- Woonkee S Jo
- Chemistry Program, New York University Abu Dhabi (NYUAD), Saadiyat Island, Abu Dhabi 129188, United Arab Emirates (UAE)
| | - Brian J Curtis
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA
| | - Mohammad Rehan
- Chemistry Program, New York University Abu Dhabi (NYUAD), Saadiyat Island, Abu Dhabi 129188, United Arab Emirates (UAE)
| | | | - David H Sherman
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA
- Departments of Medicinal Chemistry, Chemistry, and Microbiology & Immunology, University of Michigan, Ann Arbor, MI 48109USA
| | - Alan R Healy
- Chemistry Program, New York University Abu Dhabi (NYUAD), Saadiyat Island, Abu Dhabi 129188, United Arab Emirates (UAE)
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3
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Qiao S, Cheng Z, Li F. Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization. Beilstein J Org Chem 2024; 20:721-733. [PMID: 38590533 PMCID: PMC10999997 DOI: 10.3762/bjoc.20.66] [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: 12/14/2023] [Accepted: 03/21/2024] [Indexed: 04/10/2024] Open
Abstract
Chemoenzymatic strategies that combine synthetic and enzymatic transformations offer efficient approaches to yield target molecules, which have been increasingly employed in the synthesis of bioactive natural products. In the biosynthesis of macrocyclic nonribosomal peptides, polyketides, and their hybrids, thioesterase (TE) domains play a significant role in late-stage macrocyclization. These domains can accept mimics of native substrates in vitro and exhibit potential for use in total synthesis. This review summarizes the recent advances of TE domains in the chemoenzymatic synthesis for these natural products that aim to address the common issues in classical synthetic approaches and increase synthetic efficiencies, which have the potential to facilitate further pharmaceutical research.
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Affiliation(s)
- Senze Qiao
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Zhongyu Cheng
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Fuzhuo Li
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
- Key Laboratory of Smart Drug Delivery (Ministry of Education), State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 201203, China
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4
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Wang Y, Torma KJ, Pyser JB, Zimmerman PM, Narayan ARH. Substrate-Selective Catalysis Enabled Synthesis of Azaphilone Natural Products. ACS CENTRAL SCIENCE 2024; 10:708-716. [PMID: 38559303 PMCID: PMC10979483 DOI: 10.1021/acscentsci.3c01405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/05/2024] [Accepted: 02/16/2024] [Indexed: 04/04/2024]
Abstract
Achieving substrate-selectivity is a central element of nature's approach to synthesis. By relying on the ability of a catalyst to discriminate between components in a mixture, control can be exerted over which molecules will move forward in a synthesis. This approach can be powerful when realized but can be challenging to duplicate in the laboratory. In this work, substrate-selective catalysis is leveraged to discriminate between two intermediates that exist in equilibrium, subsequently directing the final cyclization to arrive at either the linear or angular tricyclic core common to subsets of azaphilone natural products. By using a flavin-dependent monooxygenase (FDMO) in sequence with an acyl transferase (AT), the conversion of several orcinaldehyde substrates directly to the corresponding linear tricyclic azaphilones in a single reaction vessel was achieved. Further, mechanistic studies support that a substrate equilibrium together with enzyme substrate selectivity play an import role in the selectivity of the final cyclization step. Using this strategy, five azaphilone natural products were synthesized for the first time as well as a number of unnatural derivatives thereof.
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Affiliation(s)
- Ye Wang
- Life
Sciences Institute, Department of Chemistry, University of
Michigan, Ann Arbor, Michigan 48109, United States
| | - Katherine J. Torma
- Life
Sciences Institute, Department of Chemistry, University of
Michigan, Ann Arbor, Michigan 48109, United States
| | - Joshua B. Pyser
- Life
Sciences Institute, Department of Chemistry, University of
Michigan, Ann Arbor, Michigan 48109, United States
| | - Paul M. Zimmerman
- Life
Sciences Institute, Department of Chemistry, University of
Michigan, Ann Arbor, Michigan 48109, United States
| | - Alison R. H. Narayan
- Life
Sciences Institute, Department of Chemistry, University of
Michigan, Ann Arbor, Michigan 48109, United States
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5
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Guth FM, Lindner F, Rydzek S, Peil A, Friedrich S, Hauer B, Hahn F. Rieske Oxygenase-Catalyzed Oxidative Late-Stage Functionalization during Complex Antifungal Polyketide Biosynthesis. ACS Chem Biol 2023; 18:2450-2456. [PMID: 37948749 DOI: 10.1021/acschembio.3c00498] [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: 11/12/2023]
Abstract
Rieske oxygenases (ROs) from natural product biosynthetic pathways are a poorly studied group of enzymes with significant potential as oxidative functionalization biocatalysts. A study on the ROs JerL, JerP, and AmbP from the biosynthetic pathways of jerangolid A and ambruticin VS-3 is described. Their activity was successfully reconstituted using whole-cell bioconversion systems coexpressing the ROs and their respective natural flavin-dependent reductase (FDR) partners. Feeding authentic biosynthetic intermediates and synthetic surrogates to these strains confirmed the involvement of the ROs in hydroxymethylpyrone and dihydropyran formation and revealed crucial information about the RO's substrate specificity. The pronounced dependence of JerL and JerP on the presence of a methylenolether allowed the precise temporal assignment of RO catalysis to the ultimate steps of jerangolid biosynthesis. JerP and AmbP stand out among the biosynthetic ROs studied so far for their ability to catalyze clean tetrahydropyran desaturation without further functionalizing the formed electron-rich double bonds. This work highlights the remarkable ability of ROs to highly selectively oxidize complex molecular scaffolds.
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Affiliation(s)
- Florian M Guth
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Frederick Lindner
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Simon Rydzek
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Andreas Peil
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Steffen Friedrich
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Bernhard Hauer
- Institute of Technical Biochemistry, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Frank Hahn
- Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Department of Chemistry, Universität Bayreuth, 95447 Bayreuth, Germany
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6
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Paulsel TQ, Williams GJ. Current State-of-the-Art Toward Chemoenzymatic Synthesis of Polyketide Natural Products. Chembiochem 2023; 24:e202300386. [PMID: 37615926 PMCID: PMC10964317 DOI: 10.1002/cbic.202300386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/19/2023] [Accepted: 08/21/2023] [Indexed: 08/25/2023]
Abstract
Polyketide natural products have significant promise as pharmaceutical targets for human health and as molecular tools to probe disease and complex biological systems. While the biosynthetic logic of polyketide synthases (PKS) is well-understood, biosynthesis of designer polyketides remains challenging due to several bottlenecks, including substrate specificity constraints, disrupted protein-protein interactions, and protein solubility and folding issues. Focusing on substrate specificity, PKSs are typically interrogated using synthetic thioesters. PKS assembly lines and their products offer a wealth of information when studied in a chemoenzymatic fashion. This review provides an overview of the past two decades of polyketide chemoenzymatic synthesis and their contributions to the field of chemical biology. These synthetic strategies have successfully yielded natural product derivatives while providing critical insights into enzymatic promiscuity and mechanistic activity.
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Affiliation(s)
- Thaddeus Q Paulsel
- Department of Chemistry, NC State University Dabney Hall, Room 208, Campus Box 8204, 2620 Yarbrough Dr., NC State University, Raleigh, NC 27695, USA
- Comparative Medicine Institute, NC State University, 1060 William Moore Dr., NC State University, Raleigh, NC 27607, USA
| | - Gavin J Williams
- Department of Chemistry, NC State University Dabney Hall, Room 208, Campus Box 8204, 2620 Yarbrough Dr., NC State University, Raleigh, NC 27695, USA
- Comparative Medicine Institute, NC State University, 1060 William Moore Dr., NC State University, Raleigh, NC 27607, USA
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7
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Wang L, Zhu M, Zhang Q, Zhai S, Zhu Y, Zhang H, Zhang C. Biosynthetic Diversification of Fidaxomicin Aglycones by Heterologous Expression and Promoter Refactoring. JOURNAL OF NATURAL PRODUCTS 2023; 86:986-993. [PMID: 37042607 DOI: 10.1021/acs.jnatprod.3c00001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Fidaxomicin (Dificid) is a commercial macrolide antibiotic for treating Clostridium difficile infection. Total synthesis of fidaxomicin and its aglycone had been achieved through different synthetic schemes. In this study, an alternative biological route to afford the unique 18-membered macrolactone aglycone of fidaxomicin was developed. The promoter refactored fidaxomicin biosynthetic gene cluster from Dactylosporangium aurantiacum was expressed in the commonly used host Streptomyces albus J1074, thereby delivering five structurally diverse fidaxomicin aglycones with the corresponding titers ranging from 4.9 to 15.0 mg L-1. In general, these results validated a biological strategy to construct and diversify fidaxomicin aglycones on the basis of promoter refactoring and heterologous expression.
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Affiliation(s)
- Lijuan Wang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
| | - Mengyi Zhu
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
| | - Qingbo Zhang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, People's Republic of China
- Sanya Institute of Ocean Eco-Environmental Engineering, Yazhou Scientific Bay, Sanya 572000, People's Republic of China
| | - Shilan Zhai
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China
| | - Yiguang Zhu
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, People's Republic of China
- Sanya Institute of Ocean Eco-Environmental Engineering, Yazhou Scientific Bay, Sanya 572000, People's Republic of China
| | - Haibo Zhang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, People's Republic of China
- Sanya Institute of Ocean Eco-Environmental Engineering, Yazhou Scientific Bay, Sanya 572000, People's Republic of China
| | - Changsheng Zhang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, People's Republic of China
- Sanya Institute of Ocean Eco-Environmental Engineering, Yazhou Scientific Bay, Sanya 572000, People's Republic of China
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8
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Chemoenzymatic synthesis of fluorinated polyketides. Nat Chem 2022; 14:1000-1006. [PMID: 35879443 PMCID: PMC9832397 DOI: 10.1038/s41557-022-00996-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 06/10/2022] [Indexed: 01/13/2023]
Abstract
Modification of polyketides with fluorine offers a promising approach to develop new pharmaceuticals. While synthetic chemical methods for site-selective incorporation of fluorine in complex molecules have improved in recent years, approaches for the biosynthetic incorporation of fluorine in natural compounds are still rare. Here, we report a strategy to introduce fluorine into complex polyketides during biosynthesis. We exchanged the native acyltransferase domain of a polyketide synthase, which acts as the gatekeeper for the selection of extender units, with an evolutionarily related but substrate tolerant domain from metazoan type I fatty acid synthase. The resulting polyketide-synthase/fatty-acid-synthase hybrid can utilize fluoromalonyl coenzyme A and fluoromethylmalonyl coenzyme A for polyketide chain extension, introducing fluorine or fluoro-methyl units in polyketide scaffolds. We demonstrate the feasibility of our approach in the chemoenzymatic synthesis of fluorinated 12- and 14-membered macrolactones and fluorinated derivatives of the macrolide antibiotics YC-17 and methymycin.
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9
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Thiocysteine lyases as polyketide synthase domains installing hydropersulfide into natural products and a hydropersulfide methyltransferase. Nat Commun 2021; 12:5672. [PMID: 34584078 PMCID: PMC8479088 DOI: 10.1038/s41467-021-25798-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/01/2021] [Indexed: 12/02/2022] Open
Abstract
Nature forms S-S bonds by oxidizing two sulfhydryl groups, and no enzyme installing an intact hydropersulfide (-SSH) group into a natural product has been identified to date. The leinamycin (LNM) family of natural products features intact S-S bonds, and previously we reported an SH domain (LnmJ-SH) within the LNM hybrid nonribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) assembly line as a cysteine lyase that plays a role in sulfur incorporation. Here we report the characterization of an S-adenosyl methionine (SAM)-dependent hydropersulfide methyltransferase (GnmP) for guangnanmycin (GNM) biosynthesis, discovery of hydropersulfides as the nascent products of the GNM and LNM hybrid NRPS-PKS assembly lines, and revelation of three SH domains (GnmT-SH, LnmJ-SH, and WsmR-SH) within the GNM, LNM, and weishanmycin (WSM) hybrid NRPS-PKS assembly lines as thiocysteine lyases. Based on these findings, we propose a biosynthetic model for the LNM family of natural products, featuring thiocysteine lyases as PKS domains that directly install a -SSH group into the GNM, LNM, or WSM polyketide scaffold. Genome mining reveals that SH domains are widespread in Nature, extending beyond the LNM family of natural products. The SH domains could also be leveraged as biocatalysts to install an -SSH group into other biologically relevant scaffolds. Enzymes installing an intact hydropersulfide (-SSH) group into natural products have so far not been identified. Here, the authors report the characterization of an S-adenosyl methionine-dependent hydropersulfide methyltransferase (GnmP) for guangnanmycin biosynthesis, and identification of three SH domains within several NRPS-PKS assembly lines as thiocysteine lyases.
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Adrover-Castellano ML, Schmidt JJ, Sherman DH. Biosynthetic Cyclization Catalysts for the Assembly of Peptide and Polyketide Natural Products. ChemCatChem 2021; 13:2095-2116. [PMID: 34335987 PMCID: PMC8320681 DOI: 10.1002/cctc.202001886] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Indexed: 12/13/2022]
Abstract
Many biologically active natural products are synthesized by nonribosomal peptide synthetases (NRPSs), polyketide synthases (PKSs) and their hybrids. These megasynthetases contain modules possessing distinct catalytic domains that allow for substrate initiation, chain extension, processing and termination. At the end of a module, a terminal domain, usually a thioesterase (TE), is responsible for catalyzing the release of the NRPS or PKS as a linear or cyclized product. In this review, we address the general cyclization mechanism of the TE domain, including oligomerization and the fungal C-C bond forming Claisen-like cyclases (CLCs). Additionally, we include examples of cyclization catalysts acting within or at the end of a module. Furthermore, condensation-like (CT) domains, terminal reductase (R) domains, reductase-like domains that catalyze Dieckmann condensation (RD), thioesterase-like Dieckmann cyclases, trans-acting TEs from the penicillin binding protein (PBP) enzyme family, product template (PT) domains and others will also be reviewed. The studies summarized here highlight the remarkable diversity of NRPS and PKS cyclization catalysts for the production of biologically relevant, complex cyclic natural products and related compounds.
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Affiliation(s)
| | - Jennifer J Schmidt
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA)
| | - David H Sherman
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA)
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11
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Ueoka R, Hashimoto J, Kozone I, Hashimoto T, Kudo K, Kagaya N, Suenaga H, Ikeda H, Shin-Ya K. A novel methymycin analog, 12-ketomethymycin N-oxide, produced by the heterologous expression of the large pikromycin/methymycin biosynthetic gene cluster of Streptomyces sp. AM4900. Biosci Biotechnol Biochem 2021; 85:890-894. [PMID: 33590846 DOI: 10.1093/bbb/zbaa111] [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: 11/05/2020] [Accepted: 12/11/2020] [Indexed: 11/13/2022]
Abstract
A novel methymycin analog, 12-ketomethymycin N-oxide, was produced by the heterologous expression of the pikromycin/methymycin biosynthetic gene cluster of Streptomyces sp. AM4900 together with 12-ketomethymycin, which was only isolated by the biotransformation of the synthetic intermediate before. Their structures were determined by the spectroscopic data and the chemical derivatization. 12-Ketomethymycin showed a weak cytotoxicity against SKOV-3 and Jurkat cells, although its N-oxide analog did not show any activity. Both showed no antibacterial activities against Escherichia coli and Micrococcus luteus.
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Affiliation(s)
- Reiko Ueoka
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Junko Hashimoto
- Japan Biological Informatics Consortium (JBIC), Tokyo, Japan
| | - Ikuko Kozone
- Japan Biological Informatics Consortium (JBIC), Tokyo, Japan
| | - Takuya Hashimoto
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Kei Kudo
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Noritaka Kagaya
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Hikaru Suenaga
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Haruo Ikeda
- Kitasato Institute for Life Sciences, Kitasato University, Kanagawa, Japan
| | - Kazuo Shin-Ya
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.,Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
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12
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Hahn F, Guth FM. The ambruticins and jerangolids - chemistry, biology and chemoenzymatic synthesis of potent antifungal drug candidates. Nat Prod Rep 2020; 37:1300-1315. [PMID: 32420573 DOI: 10.1039/d0np00012d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: 1977 to 2020The ambruticins and jerangolids are myxobacterial reduced polyketides, which are produced via highly unusual biosynthetic pathways containing a plethora of non-canonical enzymatic transformations. Since the discovery of the first congeners in the late 1970s, they have been in the focus of drug development due to their good antifungal activity and low toxicity in mammals, which result from interaction with an unusual innercellular target in fungi. Despite significant efforts, which have led to the development of various total syntheses, their structural complexity has yet avoided full exploitation of their pharmacological potential. This article summarises biological, total and semisynthetic as well as biosynthetic studies on both compounds. An outlook on the biosynthesis-based approaches to them and their derivatives is presented. Due to the structural and biosynthetic characteristics of the ambruticins and jerangolids, chemoenzymatic processes that make use of their biosynthetic pathway enzymes are particularly promising to gain efficient access to derivative libraries for structure activity relationship studies.
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Affiliation(s)
- Frank Hahn
- Department of Chemistry, University of Bayreuth, 51427 Bayreuth, Germany.
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13
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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Aaron A. Koch
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Jennifer J. Schmidt
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Andrew N. Lowell
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Current address: Department of Chemistry Virginia Tech Blacksburg VA 24061 USA
| | - Douglas A. Hansen
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Katherine M. Coburn
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Joseph A. Chemler
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - David H. Sherman
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology The University of Michigan USA
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14
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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020; 59:13575-13580. [PMID: 32357274 DOI: 10.1002/anie.202004991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Indexed: 11/09/2022]
Abstract
Engineering polyketide synthases (PKS) to produce new metabolites requires an understanding of catalytic points of failure during substrate processing. Growing evidence indicates the thioesterase (TE) domain as a significant bottleneck within engineered PKS systems. We created a series of hybrid PKS modules bearing exchanged TE domains from heterologous pathways and challenged them with both native and non-native polyketide substrates. Reactions pairing wildtype PKS modules with non-native substrates primarily resulted in poor conversions to anticipated macrolactones. Likewise, product formation with native substrates and hybrid PKS modules bearing non-cognate TE domains was severely reduced. In contrast, non-native substrates were converted by most hybrid modules containing a substrate compatible TE, directly implicating this domain as the major catalytic gatekeeper and highlighting its value as a target for protein engineering to improve analog production in PKS pathways.
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Affiliation(s)
- Aaron A Koch
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Jennifer J Schmidt
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Andrew N Lowell
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Current address: Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Douglas A Hansen
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Katherine M Coburn
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Joseph A Chemler
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - David H Sherman
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology, The University of Michigan, USA
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15
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Dhakal D, Sohng JK, Pandey RP. Engineering actinomycetes for biosynthesis of macrolactone polyketides. Microb Cell Fact 2019; 18:137. [PMID: 31409353 PMCID: PMC6693128 DOI: 10.1186/s12934-019-1184-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/02/2019] [Indexed: 12/18/2022] Open
Abstract
Actinobacteria are characterized as the most prominent producer of natural products (NPs) with pharmaceutical importance. The production of NPs from these actinobacteria is associated with particular biosynthetic gene clusters (BGCs) in these microorganisms. The majority of these BGCs include polyketide synthase (PKS) or non-ribosomal peptide synthase (NRPS) or a combination of both PKS and NRPS. Macrolides compounds contain a core macro-lactone ring (aglycone) decorated with diverse functional groups in their chemical structures. The aglycon is generated by megaenzyme polyketide synthases (PKSs) from diverse acyl-CoA as precursor substrates. Further, post-PKS enzymes are responsible for allocating the structural diversity and functional characteristics for their biological activities. Macrolides are biologically important for their uses in therapeutics as antibiotics, anti-tumor agents, immunosuppressants, anti-parasites and many more. Thus, precise genetic/metabolic engineering of actinobacteria along with the application of various chemical/biological approaches have made it plausible for production of macrolides in industrial scale or generation of their novel derivatives with more effective biological properties. In this review, we have discussed versatile approaches for generating a wide range of macrolide structures by engineering the PKS and post-PKS cascades at either enzyme or cellular level in actinobacteria species, either the native or heterologous producer strains.
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Affiliation(s)
- Dipesh Dhakal
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
| | - Jae Kyung Sohng
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
- Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
| | - Ramesh Prasad Pandey
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
- Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
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16
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Kalkreuter E, Keeler AM, Malico AA, Bingham KS, Gayen AK, Williams GJ. Development of a Genetically Encoded Biosensor for Detection of Polyketide Synthase Extender Units in Escherichia coli. ACS Synth Biol 2019; 8:1391-1400. [PMID: 31134799 PMCID: PMC6915837 DOI: 10.1021/acssynbio.9b00078] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The scaffolds of polyketides are constructed via assembly of extender units based on malonyl-CoA and its derivatives that are substituted at the C2-position with diverse chemical functionality. Subsequently, a transcription-factor-based biosensor for malonyl-CoA has proven to be a powerful tool for detecting malonyl-CoA, facilitating the dynamic regulation of malonyl-CoA biosynthesis and guiding high-throughput engineering of malonyl-CoA-dependent processes. Yet, a biosensor for the detection of malonyl-CoA derivatives has yet to be reported, severely restricting the application of high-throughput synthetic biology approaches to engineering extender unit biosynthesis and limiting the ability to dynamically regulate the biosynthesis of polyketide products that are dependent on such α-carboxyacyl-CoAs. Herein, the FapR biosensor was re-engineered and optimized for a range of mCoA concentrations across a panel of E. coli strains. The effector specificity of FapR was probed by cell-free transcription-translation, revealing that a variety of non-native and non-natural acyl-thioesters are FapR effectors. This FapR promiscuity proved sufficient for the detection of the polyketide extender unit methylmalonyl-CoA in E. coli, providing the first reported genetically encoded biosensor for this important metabolite. As such, the previously unknown broad effector promiscuity of FapR provides a platform to develop new tools and approaches that can be leveraged to overcome limitations of pathways that construct diverse α-carboxyacyl-CoAs and those that are dependent on them, including biofuels, antibiotics, anticancer drugs, and other value-added products.
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Affiliation(s)
- Edward Kalkreuter
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
- Comparative Medicine Institute, NC State University, Raleigh, North Carolina 27695, United States
- Present address: Department of Chemistry, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Aaron M. Keeler
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
| | - Alexandra A. Malico
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
| | - Kyle S. Bingham
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
- Present address: UNC Chapel Hill School of Medicine, Chapel Hill, North Carolina 27516, United States
| | - Anuran K. Gayen
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
| | - Gavin J. Williams
- Department of Chemistry, NC State University, Raleigh, North Carolina 27695, United States
- Comparative Medicine Institute, NC State University, Raleigh, North Carolina 27695, United States
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17
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Fessner ND. P450 Monooxygenases Enable Rapid Late-Stage Diversification of Natural Products via C-H Bond Activation. ChemCatChem 2019; 11:2226-2242. [PMID: 31423290 PMCID: PMC6686969 DOI: 10.1002/cctc.201801829] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 01/07/2019] [Indexed: 01/07/2023]
Abstract
The biological potency of natural products has been exploited for decades. Their inherent structural complexity and natural diversity might hold the key to efficiently address the urgent need for the development of novel pharmaceuticals. At the same time, it is that very complexity, which impedes necessary chemical modifications such as structural diversification, to improve the effectiveness of the drug. For this purpose, Cytochrome P450 enzymes, which possess unique abilities to activate inert sp3-hybridised C-H bonds in a late-stage fashion, offer an attractive synthetic tool. In this review the potential of cytochrome P450 enzymes in chemoenzymatic lead diversification is illustrated discussing studies reporting late-stage functionalisations of natural products and other high-value compounds. These enzymes were proven to extend the synthetic toolbox significantly by adding to the flexibility and efficacy of synthetic strategies of natural product chemists, and scientists of other related disciplines.
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Affiliation(s)
- Nico D. Fessner
- Institute of Molecular BiotechnologyGraz University of Technology, NAWI GrazPetersgasse 148010GrazAustria
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18
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Dodge GJ, Maloney FP, Smith JL. Protein-protein interactions in "cis-AT" polyketide synthases. Nat Prod Rep 2018; 35:1082-1096. [PMID: 30188553 PMCID: PMC6207950 DOI: 10.1039/c8np00058a] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to the end of 2018 Polyketides are a valuable source of bioactive and clinically important molecules. The biosynthesis of these chemically complex molecules has led to the discovery of equally complex polyketide synthase (PKS) pathways. Crystallography has yielded snapshots of individual catalytic domains, di-domains, and multi-domains from a variety of PKS megasynthases, and cryo-EM studies have provided initial views of a PKS module in a series of defined biochemical states. Here, we review the structural and biochemical results that shed light on the protein-protein interactions critical to catalysis by PKS systems with an embedded acyltransferase. Interactions include those that occur both within and between PKS modules, as well as with accessory enzymes.
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Affiliation(s)
- Greg J Dodge
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA 48109.
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19
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Zhang W, Du L, Li F, Zhang X, Qu Z, Han L, Li Z, Sun J, Qi F, Yao Q, Sun Y, Geng C, Li S. Mechanistic Insights into Interactions between Bacterial Class I P450 Enzymes and Redox Partners. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02913] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, China
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Lei Du
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Fengwei Li
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Xingwang Zhang
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Zepeng Qu
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
| | - Lei Han
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China
| | - Zhong Li
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
| | - Jingran Sun
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Fengxia Qi
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Qiuping Yao
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Yue Sun
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Ce Geng
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
| | - Shengying Li
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
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20
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Slocum ST, Lowell AN, Tripathi A, Shende VV, Smith JL, Sherman DH. Chemoenzymatic Dissection of Polyketide β-Branching in the Bryostatin Pathway. Methods Enzymol 2018; 604:207-236. [PMID: 29779653 PMCID: PMC6327954 DOI: 10.1016/bs.mie.2018.01.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
β-Branching is an expansion upon canonical polyketide synthase extension that allows for the installation of diverse chemical moieties in several natural products. Several of these moieties are unique among natural products, including the two vinyl methylesters found in the core structure of bryostatins. This family of molecules is derived from an obligate bacterial symbiont of a sessile marine bryozoan, Bugula neritina. Within this family, bryostatin 1 has been investigated as an anticancer, neuroprotective, and immunomodulatory compound. We have turned to the biosynthetic gene cluster within the bacterial symbiont to investigate the biosynthesis of bryostatins. Recent sequencing efforts resulted in the annotation of two missing genes: bryT and bryU. Using novel chemoenzymatic techniques, we have validated these as the missing enoyl-CoA hydratase and donor acyl carrier protein, essential components of the β-branching cassette of the bryostatin pathway. Together, this cassette installs the vinyl methylester moieties essential to the activity of bryostatins.
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Affiliation(s)
- Samuel T Slocum
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States; Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - Andrew N Lowell
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States
| | - Vikram V Shende
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States
| | - Janet L Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States; Life Sciences Institute, Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States; Life Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, United States; Life Sciences Institute, Department of Chemistry, University of Michigan, Ann Arbor, MI, United States; Life Sciences Institute, Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States.
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21
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Padarti A, Kim D, Han H. Highly Stereoselective 2-Oxonia-Cope Rearrangement: A Platform Enabling At-Will Control of Regio-, Enantio-, and Diastereoselectivity in the Vinylogous Aldol Reactions of Aldehydes. Org Lett 2018; 20:756-759. [PMID: 29345942 DOI: 10.1021/acs.orglett.7b03895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A distinctly different approach for the vinylogous aldolation of aldehydes is described, which exploits 2-oxonia-Cope rearrangement reactions between two readily available partners, a set of rationally designed chiral homoallylic alcohol synthons and aldehydes, under simple conditions. In these processes, chirality transfer from the former to the latter is nearly perfect, giving rise to excellent enantio- and diastereoselectivity without the regioselectivity issue associated with traditional vinylogous aldol reactions.
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Affiliation(s)
- Akhil Padarti
- Department of Chemistry, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Dongeun Kim
- Department of Chemistry, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Hyunsoo Han
- Department of Chemistry, University of Texas at San Antonio , San Antonio, Texas 78249, United States
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22
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Hansen DA, Koch AA, Sherman DH. Identification of a Thioesterase Bottleneck in the Pikromycin Pathway through Full-Module Processing of Unnatural Pentaketides. J Am Chem Soc 2017; 139:13450-13455. [PMID: 28836772 DOI: 10.1021/jacs.7b06432] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Polyketide biosynthetic pathways have been engineered to generate natural product analogs for over two decades. However, manipulation of modular type I polyketide synthases (PKSs) to make unnatural metabolites commonly results in attenuated yields or entirely inactive pathways, and the mechanistic basis for compromised production is rarely elucidated since rate-limiting or inactive domain(s) remain unidentified. Accordingly, we synthesized and assayed a series of modified pikromycin (Pik) pentaketides that mimic early pathway engineering to probe the substrate tolerance of the PikAIII-TE module in vitro. Truncated pentaketides were processed with varying efficiencies to corresponding macrolactones, while pentaketides with epimerized chiral centers were poorly processed by PikAIII-TE and failed to generate 12-membered ring products. Isolation and identification of extended but prematurely offloaded shunt products suggested that the Pik thioesterase (TE) domain has limited substrate flexibility and functions as a gatekeeper in the processing of unnatural substrates. Synthesis of an analogous hexaketide with an epimerized nucleophilic hydroxyl group allowed for direct evaluation of the substrate stereoselectivity of the excised TE domain. The epimerized hexaketide failed to undergo cyclization and was exclusively hydrolyzed, confirming the TE domain as a key catalytic bottleneck. In an accompanying paper , we engineer the standalone Pik thioesterase to yield a thioesterase (TES148C) and module (PikAIII-TES148C) that display gain-of-function processing of substrates with inverted hydroxyl groups.
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Affiliation(s)
- Douglas A Hansen
- Life Sciences Institute, ‡Department of Medicinal Chemistry, §Cancer Biology Graduate Program, ⊥Department of Chemistry, and ∥Department of Microbiology & Immunology, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Aaron A Koch
- Life Sciences Institute, ‡Department of Medicinal Chemistry, §Cancer Biology Graduate Program, ⊥Department of Chemistry, and ∥Department of Microbiology & Immunology, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - David H Sherman
- Life Sciences Institute, ‡Department of Medicinal Chemistry, §Cancer Biology Graduate Program, ⊥Department of Chemistry, and ∥Department of Microbiology & Immunology, University of Michigan , Ann Arbor, Michigan 48109, United States
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23
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Almutairi MM, Svetlov MS, Hansen DA, Khabibullina NF, Klepacki D, Kang HY, Sherman DH, Vázquez-Laslop N, Polikanov YS, Mankin AS. Co-produced natural ketolides methymycin and pikromycin inhibit bacterial growth by preventing synthesis of a limited number of proteins. Nucleic Acids Res 2017; 45:9573-9582. [PMID: 28934499 PMCID: PMC5766166 DOI: 10.1093/nar/gkx673] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/05/2017] [Accepted: 07/21/2017] [Indexed: 01/01/2023] Open
Abstract
Antibiotics methymycin (MTM) and pikromycin (PKM), co-produced by Streptomyces venezuelae, represent minimalist macrolide protein synthesis inhibitors. Unlike other macrolides, which carry several side chains, a single desosamine sugar is attached to the macrolactone ring of MTM and PKM. In addition, the macrolactone scaffold of MTM is smaller than in other macrolides. The unusual structure of MTM and PKM and their simultaneous secretion by S. venezuelae bring about the possibility that two compounds would bind to distinct ribosomal sites. However, by combining genetic, biochemical and crystallographic studies, we demonstrate that MTM and PKM inhibit translation by binding to overlapping sites in the ribosomal exit tunnel. Strikingly, while MTM and PKM readily arrest the growth of bacteria, ∼40% of cellular proteins continue to be synthesized even at saturating concentrations of the drugs. Gel electrophoretic analysis shows that compared to other ribosomal antibiotics, MTM and PKM prevent synthesis of a smaller number of cellular polypeptides illustrating a unique mode of action of these antibiotics.
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Affiliation(s)
- Mashal M. Almutairi
- Center for Biomolecular Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Maxim S. Svetlov
- Center for Biomolecular Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Douglas A. Hansen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nelli F. Khabibullina
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Dorota Klepacki
- Center for Biomolecular Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Han-Young Kang
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nora Vázquez-Laslop
- Center for Biomolecular Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Yury S. Polikanov
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Alexander S. Mankin
- Center for Biomolecular Sciences, University of Illinois, Chicago, IL 60607, USA
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24
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Lowell AN, DeMars MD, Slocum ST, Yu F, Anand K, Chemler JA, Korakavi N, Priessnitz JK, Park SR, Koch AA, Schultz PJ, Sherman DH. Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C-H Functionalization. J Am Chem Soc 2017; 139:7913-7920. [PMID: 28525276 PMCID: PMC5532807 DOI: 10.1021/jacs.7b02875] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total synthesis of the juvenimicin, M-4365, and rosamicin classes of macrolide antibiotics via late-stage diversification. Synthetic chemistry was employed to generate the tylactone hexaketide chain elongation intermediate that was accepted by the juvenimicin (Juv) ketosynthase of the penultimate JuvEIV PKS module. The hexaketide is processed through two complete modules (JuvEIV and JuvEV) in vitro, which catalyze elongation and functionalization of two ketide units followed by cyclization of the resulting octaketide into tylactone. After macrolactonization, a combination of in vivo glycosylation, selective in vitro cytochrome P450-mediated oxidation, and chemical oxidation was used to complete the scalable construction of a series of macrolide natural products in as few as 15 linear steps (21 total) with an overall yield of 4.6%.
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Affiliation(s)
- Andrew N. Lowell
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Matthew D. DeMars
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Samuel T. Slocum
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Fengan Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Krithika Anand
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph A. Chemler
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nisha Korakavi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jennifer K. Priessnitz
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sung Ryeol Park
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aaron A. Koch
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Pamela J. Schultz
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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25
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Brzozowski RS, Wuest WM. Twelve-membered macrolactones: privileged scaffolds for the development of new therapeutics. Chem Biol Drug Des 2017; 89:169-191. [PMID: 27153932 DOI: 10.1111/cbdd.12783] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 12/15/2022]
Abstract
Natural products commonly produced as secondary metabolites of various plants and micro-organisms represent a diverse chemical space of compounds. The diversity of natural products makes them an attractive target for interrogation by both chemists and biologists alike. Indeed, the study of 12-membered macrolactones has already led to the discovery of lead drug compounds and new biological targets, which has motivated the development of diverted total synthetic routes to libraries of analogs. This review explores the discovery, biological characterization, and synthesis of several 12-membered macrolactones, exploiting examples that underscore their importance in the drug discovery field. It is our hope that this review will motivate further interest in this class of natural products, a group of molecules that we think merit the classification of 'privileged scaffolds' within the medicinal chemistry community, to further investigate and develop novel compounds with promising bioactivity.
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Affiliation(s)
| | - William M Wuest
- Department of Chemistry, Temple University, Philadelphia, PA, USA
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26
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Varela A, Garve LKB, Leonori D, Aggarwal VK. Stereocontrolled Total Synthesis of (-)-Stemaphylline. Angew Chem Int Ed Engl 2017; 56:2127-2131. [PMID: 28097799 PMCID: PMC5484348 DOI: 10.1002/anie.201611273] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Indexed: 11/09/2022]
Abstract
Homologation of readily available α-boryl pyrrolidines with metal carbenoids is especially challenging even when good leaving groups (Cl- ) are employed. By performing a solvent switch from Et2 O to CHCl3 , efficient 1,2-metalate rearrangement of the intermediate boronate occurs with both halide and ester leaving groups. The methodology was used in the total synthesis of the Stemona alkaloid (-)-stemaphylline in just 11 steps (longest linear sequence), with high stereocontrol (>20:1 d.r.) and 11 % overall yield. The synthesis also features a late-stage lithiation-borylation reaction with a tertiary amine containing carbenoid.
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Affiliation(s)
- Ana Varela
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | | | - Daniele Leonori
- School of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK
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27
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Koryakina I, Kasey C, McArthur JB, Lowell AN, Chemler JA, Li S, Hansen DA, Sherman DH, Williams GJ. Inversion of Extender Unit Selectivity in the Erythromycin Polyketide Synthase by Acyltransferase Domain Engineering. ACS Chem Biol 2017; 12:114-123. [PMID: 28103677 DOI: 10.1021/acschembio.6b00732] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Acyltransferase (AT) domains of polyketide synthases (PKSs) select extender units for incorporation into polyketides and dictate large portions of the structures of clinically relevant natural products. Accordingly, there is significant interest in engineering the substrate specificity of PKS ATs in order to site-selectively manipulate polyketide structure. However, previous attempts to engineer ATs have yielded mutant PKSs with relaxed extender unit specificity, rather than an inversion of selectivity from one substrate to another. Here, by directly screening the extender unit selectivity of mutants from active site saturation libraries of an AT from the prototypical PKS, 6-deoxyerythronolide B synthase, a set of single amino acid substitutions was discovered that dramatically impact the selectivity of the PKS with only modest reductions of product yields. One particular substitution (Tyr189Arg) inverted the selectivity of the wild-type PKS from its natural substrate toward a non-natural alkynyl-modified extender unit while maintaining more than twice the activity of the wild-type PKS with its natural substrate. The strategy and mutations described herein form a platform for combinatorial biosynthesis of site-selectively modified polyketide analogues that are modified with non-natural and non-native chemical functionality.
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Affiliation(s)
- Irina Koryakina
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
| | - Christian Kasey
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
| | | | - Andrew N. Lowell
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph A. Chemler
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Shasha Li
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Douglas A. Hansen
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Gavin J. Williams
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
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28
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Varela A, Garve LKB, Leonori D, Aggarwal VK. Stereocontrolled Total Synthesis of (−)-Stemaphylline. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611273] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ana Varela
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
| | - Lennart K. B. Garve
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
| | - Daniele Leonori
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
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29
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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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Affiliation(s)
- Matthew D. DeMars
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Fang Sheng
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, CA 92093, USA
| | - Sung Ryeol Park
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Andrew N. Lowell
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Larissa M. Podust
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, CA 92093, USA
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI 48109, USA
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30
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Hari TPA, Wilke BI, Davey JA, Boddy CN. Diastereoseletive Transannular Oxa-Conjugate Addition Generates the 2,6-cis-Disubstituted Tetrahydropyran of Neopeltolide. J Org Chem 2015; 81:415-23. [PMID: 26675500 DOI: 10.1021/acs.joc.5b02014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Transannular 2,6-disubstituted pyrans, like the one found in the cytotoxic marine natural product neopeltolide, are a key functional group in many polyketides. While oxa-conjugate additions have been shown to provide direct and rapid access to tetrahydropyrans in acyclic neopeltolide intermediates, a transannular strategy for construction of this ring system in a macrocyclic core has not been investigated. In this study, we demonstrate that a transannular oxa-conjugate addition strategy is a viable approach to the construction of the bicyclic core of neopeltolide. We show that transannular addition occurs readily with an α,β-unsaturated ketone as the Michael acceptor and does not occur when an α,β-unsaturated ester is the Michael acceptor. Our data indicates that oxa-conjugate addition is reversible and that the stereochemical outcome can be under thermodynamic control. Using computational chemistry, we show that the lowest energy diastereomer is the desired cis-pyran found in neopeltolide, and we experimentally demonstrate that the trans and cis diastereomers are interconvertible under reaction conditions with the cis-pyran product predominating. This oxa-conjugate addition strategy should provide a viable route to accessing the fully elaborated macrocyclic core of neopeltolide.
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Affiliation(s)
- Taylor P A Hari
- Department of Chemistry & Biomolecular Sciences, University of Ottawa , Ottawa, Ontario, Canada K1N 6N5
| | - Burkardt I Wilke
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - James A Davey
- Department of Chemistry & Biomolecular Sciences, University of Ottawa , Ottawa, Ontario, Canada K1N 6N5
| | - Christopher N Boddy
- Department of Chemistry & Biomolecular Sciences, University of Ottawa , Ottawa, Ontario, Canada K1N 6N5
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31
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Resistance to ketolide antibiotics by coordinated expression of rRNA methyltransferases in a bacterial producer of natural ketolides. Proc Natl Acad Sci U S A 2015; 112:12956-61. [PMID: 26438831 DOI: 10.1073/pnas.1512090112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ketolides are promising new antimicrobials effective against a broad range of Gram-positive pathogens, in part because of the low propensity of these drugs to trigger the expression of resistance genes. A natural ketolide pikromycin and a related compound methymycin are produced by Streptomyces venezuelae strain ATCC 15439. The producer avoids the inhibitory effects of its own antibiotics by expressing two paralogous rRNA methylase genes pikR1 and pikR2 with seemingly redundant functions. We show here that the PikR1 and PikR2 enzymes mono- and dimethylate, respectively, the N6 amino group in 23S rRNA nucleotide A2058. PikR1 monomethylase is constitutively expressed; it confers low resistance at low fitness cost and is required for ketolide-induced activation of pikR2 to attain high-level resistance. The regulatory mechanism controlling pikR2 expression has been evolutionary optimized for preferential activation by ketolide antibiotics. The resistance genes and the induction mechanism remain fully functional when transferred to heterologous bacterial hosts. The anticipated wide use of ketolide antibiotics could promote horizontal transfer of these highly efficient resistance genes to pathogens. Taken together, these findings emphasized the need for surveillance of pikR1/pikR2-based bacterial resistance and the preemptive development of drugs that can remain effective against the ketolide-specific resistance mechanism.
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32
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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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Affiliation(s)
| | | | | | - Mark O'Neil-Johnson
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Russell B Williams
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Courtney Starks
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
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33
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Use of a biosynthetic intermediate to explore the chemical diversity of pseudo-natural fungal polyketides. Nat Chem 2015; 7:737-43. [DOI: 10.1038/nchem.2308] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/23/2015] [Indexed: 01/20/2023]
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34
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Bernard SM, Akey DL, Tripathi A, Park SR, Konwerski JR, Anzai Y, Li S, Kato F, Sherman DH, Smith JL. Structural basis of substrate specificity and regiochemistry in the MycF/TylF family of sugar O-methyltransferases. ACS Chem Biol 2015; 10:1340-51. [PMID: 25692963 DOI: 10.1021/cb5009348] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sugar moieties in natural products are frequently modified by O-methylation. In the biosynthesis of the macrolide antibiotic mycinamicin, methylation of a 6'-deoxyallose substituent occurs in a stepwise manner first at the 2'- and then the 3'-hydroxyl groups to produce the mycinose moiety in the final product. The timing and placement of the O-methylations impact final stage C-H functionalization reactions mediated by the P450 monooxygenase MycG. The structural basis of pathway ordering and substrate specificity is unknown. A series of crystal structures of MycF, the 3'-O-methyltransferase, including the free enzyme and complexes with S-adenosyl homocysteine (SAH), substrate, product, and unnatural substrates, show that SAM binding induces substantial ordering that creates the binding site for the natural substrate, and a bound metal ion positions the substrate for catalysis. A single amino acid substitution relaxed the 2'-methoxy specificity but retained regiospecificity. The engineered variant produced a new mycinamicin analog, demonstrating the utility of structural information to facilitate bioengineering approaches for the chemoenzymatic synthesis of complex small molecules containing modified sugars. Using the MycF substrate complex and the modeled substrate complex of a 4'-specific homologue, active site residues were identified that correlate with the 3' or 4' specificity of MycF family members and define the protein and substrate features that direct the regiochemistry of methyltransfer. This classification scheme will be useful in the annotation of new secondary metabolite pathways that utilize this family of enzymes.
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Affiliation(s)
- Steffen M. Bernard
- Chemical
Biology Doctoral Program, University of Michigan, Ann Arbor, Michigan 48109, United States
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David L. Akey
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ashootosh Tripathi
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sung Ryeol Park
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jamie R. Konwerski
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yojiro Anzai
- Faculty
of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Shengying Li
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Fumio Kato
- Faculty
of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - David H. Sherman
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Departments of Medicinal Chemistry, Chemistry, and Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Janet L. Smith
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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35
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Hansen D, Koch AA, Sherman DH. Substrate controlled divergence in polyketide synthase catalysis. J Am Chem Soc 2015; 137:3735-8. [PMID: 25730816 PMCID: PMC4379966 DOI: 10.1021/ja511743n] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Indexed: 01/21/2023]
Abstract
Biochemical characterization of polyketide synthases (PKSs) has relied on synthetic substrates functionalized as electrophilic esters to acylate the enzyme and initiate the catalytic cycle. In these efforts, N-acetylcysteamine thioesters have typically been employed for in vitro studies of full PKS modules as well as excised domains. However, substrate engineering approaches to control the catalytic cycle of a full PKS module harboring multiple domains remain underexplored. This study examines a series of alternatively activated native hexaketide substrates on the catalytic outcome of PikAIV, the sixth and final module of the pikromycin (Pik) pathway. We demonstrate the ability to control product formation with greater than 10:1 selectivity for either full module catalysis, leading to a 14-membered macrolactone, or direct cyclization to a 12-membered ring. This outcome was achieved through modifying the type of hexaketide ester employed, demonstrating the utility of substrate engineering in PKS functional studies and biocatalysis.
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Affiliation(s)
- Douglas
A. Hansen
- Life Sciences Institute, and Department of
Medicinal Chemistry, Cancer Biology Graduate
Program, Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aaron A. Koch
- Life Sciences Institute, and Department of
Medicinal Chemistry, Cancer Biology Graduate
Program, Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life Sciences Institute, and Department of
Medicinal Chemistry, Cancer Biology Graduate
Program, Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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36
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Architecture of the polyketide synthase module: surprises from electron cryo-microscopy. Curr Opin Struct Biol 2015; 31:9-19. [PMID: 25791608 DOI: 10.1016/j.sbi.2015.02.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 01/16/2023]
Abstract
Modular polyketide synthases (PKS) produce a vast array of bioactive molecules that are the basis of many highly valued pharmaceuticals. The biosynthesis of these compounds is based on ordered assembly lines of multi-domain modules, each extending and modifying a specific chain-elongation intermediate before transfer to the next module for further processing. The first 3D structures of a full polyketide synthase module in different functional states were obtained recently by electron cryo-microscopy. The unexpected module architecture revealed a striking evolutionary divergence of the polyketide synthase compared to its metazoan fatty acid synthase homolog, as well as remarkable conformational rearrangements dependent on its biochemical state during the full catalytic cycle. The design and dynamics of the module are highly optimized for both catalysis and fidelity in the construction of complex, biologically active natural products.
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37
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38
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The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2013. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.09.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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39
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Abstract
This review covers a breakthrough in the structural biology of the gigantic modular polyketide synthases (PKS): the structural characterization of intact modules by single-particle cryo-electron microscopy and small-angle X-ray scattering.
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Affiliation(s)
- Kira J. Weissman
- Molecular and Structural Enzymology Group
- Université de Lorraine
- IMoPA
- UMR 7365
- Vandœuvre-lès-Nancy
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40
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Li Y, Fiers WD, Bernard S, Smith JL, Aldrich CC, Fecik RA. Polyketide intermediate mimics as probes for revealing cryptic stereochemistry of ketoreductase domains. ACS Chem Biol 2014; 9:2914-22. [PMID: 25299319 PMCID: PMC4273979 DOI: 10.1021/cb5006883] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/09/2014] [Indexed: 12/27/2022]
Abstract
Among natural product families, polyketides have shown the most promise for combinatorial biosynthesis of natural product-like libraries. Though recent research in the area has provided many mechanistic revelations, a basic-level understanding of kinetic and substrate tolerability is still needed before the full potential of combinatorial biosynthesis can be realized. We have developed a novel set of chemical probes for the study of ketoreductase domains of polyketide synthases. This chemical tool-based approach was validated using the ketoreductase of pikromycin module 2 (PikKR2) as a model system. Triketide substrate mimics 12 and 13 were designed to increase stability (incorporating a nonhydrolyzable thioether linkage) and minimize nonessential functionality (truncating the phosphopantetheinyl arm). PikKR2 reduction product identities as well as steady-state kinetic parameters were determined by a combination of LC-MS/MS analysis of synthetic standards and a NADPH consumption assay. The d-hydroxyl product is consistent with bioinformatic analysis and results from a complementary biochemical and molecular biological approach. When compared to widely employed substrates in previous studies, diketide 63 and trans-decalone 64, substrates 12 and 13 showed 2-10 fold lower K(M) values (2.4 ± 0.8 and 7.8 ± 2.7 mM, respectively), indicating molecular recognition of intermediate-like substrates. Due to an abundance of the nonreducable enol-tautomer, the k(cat) values were attenuated by as much as 15-336 fold relative to known substrates. This study reveals the high stereoselectivity of PikKR2 in the face of gross substrate permutation, highlighting the utility of a chemical probe-based approach in the study of polyketide ketoreductases.
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Affiliation(s)
- Yang Li
- Department
of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - William D. Fiers
- Department
of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Steffen
M. Bernard
- Chemical Biology Program, Department of Biological
Chemistry,
and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Janet L. Smith
- Chemical Biology Program, Department of Biological
Chemistry,
and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Courtney C. Aldrich
- Department
of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert A. Fecik
- Department
of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
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41
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Abstract
Natural products are important sources of pharmaceuticals, in part owing to their diverse biological activities. Enzymes from natural product biosynthetic pathways have become attractive candidates as biocatalysts for modifying the structures and bioactivities of these complex compounds. Numerous enzymes have been harvested to generate innovative scaffolds, large-scale synthesis of chiral building blocks, and semisynthesis of medicinally relevant natural product derivatives. This review discusses recent examples from three areas: (a) polyketide catalytic domain engineering geared toward synthesis of new polyketides, (b) engineering of tailoring enzymes (other than oxidative enzymes) as biocatalysts, and (c) in vitro total synthesis of natural products using purified enzyme components. With the availability of exponentially increasing genomic information and new genome mining tools, many new and powerful biocatalysts tailored for pharmaceutical synthesis will likely emerge from secondary metabolism.
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42
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Structural rearrangements of a polyketide synthase module during its catalytic cycle. Nature 2014; 510:560-4. [PMID: 24965656 PMCID: PMC4074775 DOI: 10.1038/nature13409] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 04/28/2014] [Indexed: 12/12/2022]
Abstract
The polyketide synthase (PKS) mega-enzyme assembly line uses a modular architecture to synthesize diverse and bioactive natural products that often constitute the core structures or complete chemical entities for many clinically approved therapeutic agents. The architecture of a full-length PKS module from the pikromycin pathway of Streptomyces venezuelae creates a reaction chamber for the intramodule acyl carrier protein (ACP) domain that carries building blocks and intermediates between acyltransferase, ketosynthase and ketoreductase active sites (see accompanying paper). Here we determine electron cryo-microscopy structures of a full-length pikromycin PKS module in three key biochemical states of its catalytic cycle. Each biochemical state was confirmed by bottom-up liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry. The ACP domain is differentially and precisely positioned after polyketide chain substrate loading on the active site of the ketosynthase, after extension to the β-keto intermediate, and after β-hydroxy product generation. The structures reveal the ACP dynamics for sequential interactions with catalytic domains within the reaction chamber, and for transferring the elongated and processed polyketide substrate to the next module in the PKS pathway. During the enzymatic cycle the ketoreductase domain undergoes dramatic conformational rearrangements that enable optimal positioning for reductive processing of the ACP-bound polyketide chain elongation intermediate. These findings have crucial implications for the design of functional PKS modules, and for the engineering of pathways to generate pharmacologically relevant molecules.
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43
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Abstract
Polyketide natural products constitute a broad class of compounds with diverse structural features and biological activities. Their biosynthetic machinery, represented by type I polyketide synthases (PKSs), has an architecture in which successive modules catalyse two-carbon linear extensions and keto-group processing reactions on intermediates covalently tethered to carrier domains. Here we used electron cryo-microscopy to determine sub-nanometre-resolution three-dimensional reconstructions of a full-length PKS module from the bacterium Streptomyces venezuelae that revealed an unexpectedly different architecture compared to the homologous dimeric mammalian fatty acid synthase. A single reaction chamber provides access to all catalytic sites for the intramodule carrier domain. In contrast, the carrier from the preceding module uses a separate entrance outside the reaction chamber to deliver the upstream polyketide intermediate for subsequent extension and modification. This study reveals for the first time, to our knowledge, the structural basis for both intramodule and intermodule substrate transfer in polyketide synthases, and establishes a new model for molecular dissection of these multifunctional enzyme systems.
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44
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Hughes AJ, Tibby MR, Wagner DT, Brantley JN, Keatinge-Clay AT. Investigating the reactivities of a polyketide synthase module through fluorescent click chemistry. Chem Commun (Camb) 2013; 50:5276-8. [PMID: 24196586 DOI: 10.1039/c3cc47513a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A method for monitoring in vitro polyketide synthesis has been developed whereby nonchromophoric polyketide products are made brightly fluorescent in a simple, rapid, inexpensive, and bioorthogonal manner through CuAAC with a sulforhodamine B azide derivative.
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Affiliation(s)
- Amanda Jane Hughes
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX, USA.
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Whicher JR, Smaga SS, Hansen DA, Brown WC, Gerwick WH, Sherman DH, Smith JL. Cyanobacterial polyketide synthase docking domains: a tool for engineering natural product biosynthesis. ACTA ACUST UNITED AC 2013; 20:1340-51. [PMID: 24183970 DOI: 10.1016/j.chembiol.2013.09.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/09/2013] [Accepted: 09/20/2013] [Indexed: 11/25/2022]
Abstract
Modular type I polyketide synthases (PKSs) are versatile biosynthetic systems that initiate, successively elongate, and modify acyl chains. Intermediate transfer between modules is mediated via docking domains, which are attractive targets for PKS pathway engineering to produce natural product analogs. We identified a class 2 docking domain in cyanobacterial PKSs and determined crystal structures for two docking domain pairs, revealing a distinct class 2 docking strategy for promoting intermediate transfer. The selectivity of class 2 docking interactions, demonstrated in binding and biochemical assays, could be altered by mutagenesis. We determined the ideal fusion location for exchanging class 1 and class 2 docking domains and demonstrated effective polyketide chain transfer in heterologous modules. Thus, class 2 docking domains are tools for rational bioengineering of a broad range of PKSs containing either class 1 or 2 docking domains.
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Affiliation(s)
- Jonathan R Whicher
- Chemical Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
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