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Interfacial plasticity facilitates high reaction rate of E. coli FAS malonyl-CoA:ACP transacylase, FabD. Proc Natl Acad Sci U S A 2020; 117:24224-24233. [PMID: 32929027 DOI: 10.1073/pnas.2009805117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fatty acid synthases (FASs) and polyketide synthases (PKSs) iteratively elongate and often reduce two-carbon ketide units in de novo fatty acid and polyketide biosynthesis. Cycles of chain extensions in FAS and PKS are initiated by an acyltransferase (AT), which loads monomer units onto acyl carrier proteins (ACPs), small, flexible proteins that shuttle covalently linked intermediates between catalytic partners. Formation of productive ACP-AT interactions is required for catalysis and specificity within primary and secondary FAS and PKS pathways. Here, we use the Escherichia coli FAS AT, FabD, and its cognate ACP, AcpP, to interrogate type II FAS ACP-AT interactions. We utilize a covalent crosslinking probe to trap transient interactions between AcpP and FabD to elucidate the X-ray crystal structure of a type II ACP-AT complex. Our structural data are supported using a combination of mutational, crosslinking, and kinetic analyses, and long-timescale molecular dynamics (MD) simulations. Together, these complementary approaches reveal key catalytic features of FAS ACP-AT interactions. These mechanistic inferences suggest that AcpP adopts multiple, productive conformations at the AT binding interface, allowing the complex to sustain high transacylation rates. Furthermore, MD simulations support rigid body subdomain motions within the FabD structure that may play a key role in AT activity and substrate selectivity.
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2
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Gober CM, Joullié MM. Joining Forces: Fermentation and Organic Synthesis for the Production of Complex Heterocycles. J Org Chem 2016; 81:10136-10144. [PMID: 27427903 PMCID: PMC5096955 DOI: 10.1021/acs.joc.6b01308] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Commercial application of many promising heterocyclic natural products is limited by their natural abundance. While organic synthesis provides access to many natural products, total synthesis of numerous complex molecules is not economically feasible. In recent years, the combination of fermentation and organic synthesis has provided a new route for the production of complex heterocycles that are inaccessible by typical synthetic methods. This JOCSynopsis will review examples of how this union of disciplines has overcome obstacles in both academia and industry.
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Affiliation(s)
- Claire M. Gober
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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3
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Franke J, Hertweck C. Biomimetic Thioesters as Probes for Enzymatic Assembly Lines: Synthesis, Applications, and Challenges. Cell Chem Biol 2016; 23:1179-1192. [PMID: 27693058 DOI: 10.1016/j.chembiol.2016.08.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/09/2016] [Accepted: 08/31/2016] [Indexed: 10/20/2022]
Abstract
Thioesters play essential roles in many biosynthetic pathways to fatty acids, esters, polyketides, and non-ribosomal peptides. Coenzyme A (CoA) and related phosphopantetheine thioesters are typically employed as activated acyl units for diverse C-C, C-O, and C-N coupling reactions. To study and control these enzymatic assembly lines in vitro and in vivo structurally simplified analogs such as N-acetylcysteamine (NAC) thioesters have been developed. This review gives an overview on experimental strategies enabled by synthetic NAC thioesters, such as the elucidation of complex biosynthetic pathways and enzyme mechanisms as well as precursor-directed biosynthesis and mutasynthesis. The review also summarizes synthetic protocols and protection group strategies to access these versatile synthetic tools, which are reactive and often unstable compounds. In addition, alternative phosphopantetheine thioester mimics are presented that can be used as protein tags or suicide inhibitors for protein crosslinking and off-loading probes to elucidate polyketide intermediates.
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Affiliation(s)
- Jakob Franke
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstraße 11a, 07745 Jena, Germany; Friedrich Schiller University, 07743 Jena, Germany.
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4
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Jenner M, Afonso JP, Bailey HR, Frank S, Kampa A, Piel J, Oldham NJ. Acyl-Chain Elongation Drives Ketosynthase Substrate Selectivity intrans-Acyltransferase Polyketide Synthases. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201410219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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5
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Jenner M, Afonso JP, Bailey HR, Frank S, Kampa A, Piel J, Oldham NJ. Acyl-chain elongation drives ketosynthase substrate selectivity in trans-acyltransferase polyketide synthases. Angew Chem Int Ed Engl 2014; 54:1817-21. [PMID: 25529827 DOI: 10.1002/anie.201410219] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 11/10/2014] [Indexed: 11/09/2022]
Abstract
Type I modular polyketide synthases (PKSs), which are responsible for the biosynthesis of many biologically active agents, possess a ketosynthase (KS) domain within each module to catalyze chain elongation. Acylation of the KS active site Cys residue is followed by transfer to malonyl-ACP to yield an extended β-ketoacyl chain (ACP = acyl carrier protein). To date, the precise contribution of KS selectivity in controlling product fidelity has been unclear. Six KS domains from trans-acyltransferase (trans-AT) PKSs were subjected to a mass spectrometry based elongation assay, and higher substrate selectivity was identified for the elongating step than in preceding acylation. A close correspondence between the observed KS selectivity and that predicted by phylogenetic analysis was seen. These findings provide insights into the mechanism of KS selectivity in this important group of PKSs, can serve as guidance for engineering, and show that targeted mutagenesis can be used to expand the repertoire of acceptable substrates.
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Affiliation(s)
- Matthew Jenner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (UK)
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6
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Peirú S, Gramajo HC, Menzella HG. Recombinant approaches to large polyketide molecules as potential drugs. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 7:e95-e146. [PMID: 24103720 DOI: 10.1016/j.ddtec.2010.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7
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Jiang M, Pfeifer BA. Metabolic and pathway engineering to influence native and altered erythromycin production through E. coli. Metab Eng 2013; 19:42-9. [PMID: 23747605 DOI: 10.1016/j.ymben.2013.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/24/2013] [Accepted: 05/30/2013] [Indexed: 11/16/2022]
Abstract
The heterologous production of the complex antibiotic erythromycin through Escherichia coli provides a unique challenge in metabolic engineering. In addition to introducing the 19 foreign genes needed for heterologous biosynthesis, E. coli metabolism must be engineered to provide the propionyl-CoA and (2S)-methylmalonyl-CoA substrates required to allow erythromycin formation. In this work, three different pathways to propionyl-CoA were compared in the context of supporting E. coli erythromycin biosynthesis. The comparison revealed that alternative citramalate and threonine metabolic pathways (both starting from exogenous glycerol) were capable of supporting final compound formation equal to a proven pathway reliant upon exogenous propionate. Furthermore, two pathways to (2S)-methylmalonyl-CoA were compared in the production of a novel benzyl-erythromycin analog. A pathway dependent upon exogenous methylmalonate improved selectivity and facilitated antibiotic assessment of this new analog.
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Affiliation(s)
- Ming Jiang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; Department of Chemical and Biological Engineering, The State University of New York at Buffalo, Buffalo, NY 14260, USA
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8
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Klopries S, Sundermann U, Schulz F. Quantification of N-acetylcysteamine activated methylmalonate incorporation into polyketide biosynthesis. Beilstein J Org Chem 2013; 9:664-74. [PMID: 23616811 PMCID: PMC3628877 DOI: 10.3762/bjoc.9.75] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 03/11/2013] [Indexed: 11/23/2022] Open
Abstract
Polyketides are biosynthesized through consecutive decarboxylative Claisen condensations between a carboxylic acid and differently substituted malonic acid thioesters, both tethered to the giant polyketide synthase enzymes. Individual malonic acid derivatives are typically required to be activated as coenzyme A-thioesters prior to their enzyme-catalyzed transfer onto the polyketide synthase. Control over the selection of malonic acid building blocks promises great potential for the experimental alteration of polyketide structure and bioactivity. One requirement for this endeavor is the supplementation of the bacterial polyketide fermentation system with tailored synthetic thioester-activated malonates. The membrane permeable N-acetylcysteamine has been proposed as a coenzyme A-mimic for this purpose. Here, the incorporation efficiency into different polyketides of N-acetylcysteamine activated methylmalonate is studied and quantified, showing a surprisingly high and transferable activity of these polyketide synthase substrate analogues in vivo.
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Affiliation(s)
- Stephan Klopries
- Fakultät für Chemie, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44221 Dortmund, Germany
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9
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Gao X, Wang P, Tang Y. Engineered polyketide biosynthesis and biocatalysis in Escherichia coli. Appl Microbiol Biotechnol 2010; 88:1233-42. [PMID: 20853106 PMCID: PMC2981745 DOI: 10.1007/s00253-010-2860-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 11/24/2022]
Abstract
Polyketides are important bioactive natural products biosynthesized by bacteria, fungi, and plants. The enzymes that synthesize polyketides are collectively referred to as polyketide synthases (PKSs). Because many of the natural hosts that produce polyketides are difficult to culture or manipulate, establishing a universal heterologous host that is genetically tractable has become an important goal toward the engineered biosynthesis of polyketides and analogues. Here, we summarize the recent progresses in engineering Escherichia coli as a heterologous host for reconstituting PKSs of different types. Our increased understanding of PKS enzymology and structural biology, combined with new tools in protein engineering, metabolic engineering, and synthetic biology, has firmly established E. coli as a powerful host for producing polyketides.
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Affiliation(s)
- Xue Gao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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10
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Using chemobiosynthesis and synthetic mini-polyketide synthases to produce pharmaceutical intermediates in Escherichia coli. Appl Environ Microbiol 2010; 76:5221-7. [PMID: 20543042 DOI: 10.1128/aem.02961-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant microbial whole-cell biocatalysis is a valuable approach for producing enantiomerically pure intermediates for the synthesis of complex molecules. Here, we describe a method to produce polyketide intermediates possessing multiple stereogenic centers by combining chemobiosynthesis and engineered mini-polyketide synthases (PKSs). Chemobiosynthesis allows the introduction of unnatural moieties, while a library of synthetic bimodular PKSs expressed from codon-optimized genes permits the introduction of a variety of ketide units. To validate the approach, intermediates for the synthesis of trans-9,10-dehydroepothilone D were generated. The designer molecules obtained have the potential to greatly reduce the manufacturing cost of epothilone analogues, thus facilitating their commercial development as therapeutic agents.
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11
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Betancor L, Fernández MJ, Weissman KJ, Leadlay PF. Improved catalytic activity of a purified multienzyme from a modular polyketide synthase after coexpression with Streptomyces chaperonins in Escherichia coli. Chembiochem 2009; 9:2962-6. [PMID: 19021139 DOI: 10.1002/cbic.200800475] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lorena Betancor
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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12
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Abstract
Four bacterial hosts are reviewed in the context of either native or heterologous natural product production. E. coli, B. subtilis, pseudomonads, and Streptomyces bacterial systems are presented with each having either a long-standing or more recent application to the production of therapeutic natural compounds. The four natural product classes focused upon include the polyketides, nonribosomal peptides, terpenoids, and flavonoids. From the perspective of both innate and heterologous production potential, each bacterial host is evaluated according to biological properties that would either hinder or facilitate natural product biosynthesis.
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Affiliation(s)
- Haoran Zhang
- Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts 02155, USA
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13
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Kennedy J. Mutasynthesis, chemobiosynthesis, and back to semi-synthesis: combining synthetic chemistry and biosynthetic engineering for diversifying natural products. Nat Prod Rep 2007; 25:25-34. [PMID: 18250896 DOI: 10.1039/b707678a] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combination of biological and chemical approaches for the generation of new and diverse natural products holds much promise. While mutasynthesis based approaches are still very relevant, more recent approaches have utilised genetic and metabolic engineering to generate key intermediates for chemical syntheses. This new semi-synthetic approach exploits the ability of biological systems to efficiently generate complex chiral molecules and of synthetic chemistry to elaborate these into new, or difficult to source, molecules.
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Affiliation(s)
- Jonathan Kennedy
- Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland.
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14
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Xie X, Wong WW, Tang Y. Improving simvastatin bioconversion in Escherichia coli by deletion of bioH. Metab Eng 2007; 9:379-86. [PMID: 17625941 DOI: 10.1016/j.ymben.2007.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 05/05/2007] [Accepted: 05/29/2007] [Indexed: 10/23/2022]
Abstract
Simvastatin is an important cholesterol lowering compound and is currently synthesized from the natural product lovastatin via multistep chemical synthesis. We have previously reported the use of an Escherichia coli strain BL21(DE3)/pAW31 as the host for whole-cell biocatalytic conversion of monacolin J acid to simvastatin acid. During fermentation and bioconversion, unknown E. coli enzyme(s) hydrolyzed the membrane permeable thioester substrate dimethylbutyryl-S-methyl mercaptopropionate (DMB-S-MMP) to the free acid, significantly decreased the efficiencies of the whole-cell bioconversion and the downstream purification steps. Using the Keio K-12 Singe-Gene Knockout collection, we identified BioH as the sole enzyme responsible for the observed substrate hydrolysis. Purification and reconstitution of E. coli BioH activity in vitro confirmed its function. BioH catalyzed the rapid hydrolysis of DMB-S-MMP with kcat and Km values of 260+/-45 s(-1) and 229+/-26 microM, respectively. This is in agreement with previous reports that BioH can function as a carboxylesterase towards fatty acid esters. YT2, which is a delta bioH mutant of BL21(DE3), did not hydrolyze DMB-S-MMP during prolonged fermentation and was used as an alternative host for whole-cell biocatalysis. The rate of simvastatin acid synthesis in YT2 was significantly faster than in BL21(DE3) and 99% conversion of 15 mM simvastatin acid in less than 12 h was achieved. Furthermore, the engineered host required significantly less DMB-S-MMP to be added to accomplish complete conversion. Finally, simvastatin acid synthesized using YT2 can be readily purified from fermentation broth and no additional steps to remove the hydrolyzed dimethylbutyryl-S-mercaptopropionic acid is required. Together, the proteomic and metabolic engineering approaches render the whole-cell biocatalytic process more robust and economically attractive.
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Affiliation(s)
- Xinkai Xie
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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15
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Menzella HG, Reeves CD. Combinatorial biosynthesis for drug development. Curr Opin Microbiol 2007; 10:238-45. [PMID: 17553731 DOI: 10.1016/j.mib.2007.05.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 04/09/2007] [Accepted: 05/17/2007] [Indexed: 11/17/2022]
Abstract
Combinatorial biosynthesis can refer to any strategy for the genetic engineering of natural product biosynthesis to obtain new molecules, including the use of genetics for medicinal chemistry. However, it also implies the possibility that large libraries of complex compounds might be produced to feed a modern high-throughput screening operation. This review focuses on the multi-modular enzymes that produce polyketides, nonribosomal peptides, and hybrid polyketide-peptide compounds, which are the enzymes that appear to be most amenable to truly combinatorial approaches. The recent establishment of a high-throughput strategy for testing the activity of many non-natural combinations of modules from these enzymes should help speed the advance of this technology.
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Affiliation(s)
- Hugo G Menzella
- Kosan Biosciences, Inc. 3832 Bay Center Place, Hayward, CA 94545, USA
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16
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Menzella HG, Carney JR, Santi DV. Rational design and assembly of synthetic trimodular polyketide synthases. ACTA ACUST UNITED AC 2007; 14:143-51. [PMID: 17317568 DOI: 10.1016/j.chembiol.2006.12.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 11/22/2006] [Accepted: 12/04/2006] [Indexed: 10/23/2022]
Abstract
Type I polyketide synthases (PKSs) consist of modules that add two-carbon units in polyketide backbones. Rearranging modules from different sources can yield novel enzymes that produce unnatural products, but the rules that govern module-module communication are still not well known. The construction and assay of hybrid bimodular units with synthetic PKS genes were recently reported. Here, we describe the rational design of trimodular PKSs by combining bimodular units. A cloning-expression system was developed to assemble and test 54 unnatural trimodular PKSs flanked by the loading module and the thioesterase from the erythromycin synthase. Remarkably, 96% of them produced the expected polyketide. The obtained results represent an important milestone toward the ultimate goal of making new bioactive polyketides by rational design. Additionally, these results show a path for the production of customized tetraketides by fermentation, which can be an important source of advanced intermediates to facilitate the synthesis of complex products.
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17
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Lee HY, Khosla C. Bioassay-guided evolution of glycosylated macrolide antibiotics in Escherichia coli. PLoS Biol 2007; 5:e45. [PMID: 17298179 PMCID: PMC1790958 DOI: 10.1371/journal.pbio.0050045] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 12/13/2006] [Indexed: 11/19/2022] Open
Abstract
Macrolide antibiotics such as erythromycin are clinically important polyketide natural products. We have engineered a recombinant strain of Escherichia coli that produces small but measurable quantities of the bioactive macrolide 6-deoxyerythromycin D. Bioassay-guided evolution of this strain led to the identification of an antibiotic-overproducing mutation in the mycarose biosynthesis and transfer pathway that was detectable via a colony-based screening assay. This high-throughput assay was then used to evolve second-generation mutants capable of enhanced precursor-directed biosynthesis of macrolide antibiotics. The availability of a screen for macrolide biosynthesis in E. coli offers a fundamentally new approach in dissecting modular megasynthase mechanisms as well as engineering antibiotics with novel pharmacological properties.
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Affiliation(s)
- Ho Young Lee
- Department of Chemistry, Stanford University, Stanford, California, United States of America
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, California, United States of America
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
- * To whom correspondence should be addressed. E-mail:
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18
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Xie X, Watanabe K, Wojcicki WA, Wang CCC, Tang Y. Biosynthesis of lovastatin analogs with a broadly specific acyltransferase. ACTA ACUST UNITED AC 2007; 13:1161-9. [PMID: 17113998 DOI: 10.1016/j.chembiol.2006.09.008] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2006] [Revised: 09/07/2006] [Accepted: 09/19/2006] [Indexed: 11/19/2022]
Abstract
The natural product lovastatin and its semisynthetic, more effective derivative, simvastatin, are important drugs for the treatment of hypercholesterolemia. Here, we report the biochemical characterization of a dedicated acyltransferase, LovD, encoded in the lovastatin biosynthetic pathway. We demonstrate that LovD has broad substrate specificity towards the acyl carrier, the acyl substrate, and the decalin acyl acceptor. LovD can efficiently catalyze the acyl transfer from coenzyme A thioesters or N-acetylcysteamine (SNAC) thioesters to monacolin J. When alpha-dimethylbutyryl-SNAC was used as the acyl donor, LovD was able to convert monacolin J and 6-hydroxyl-6-desmethylmonacolin J into simvastatin and huvastatin, respectively. Using the Escherichia coli LovD overexpression strain as a whole-cell biocatalyst, preparative amounts of simvastatin were synthesized in a single fermentation step. Our results demonstrate LovD is an attractive enzyme for engineered biosynthesis of pharmaceutically important cholesterol-lowering drugs.
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Affiliation(s)
- Xinkai Xie
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, California 90095, USA
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19
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Chandran SS, Menzella HG, Carney JR, Santi DV. Activating hybrid modular interfaces in synthetic polyketide synthases by cassette replacement of ketosynthase domains. ACTA ACUST UNITED AC 2006; 13:469-74. [PMID: 16720267 DOI: 10.1016/j.chembiol.2006.02.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 02/16/2006] [Accepted: 02/17/2006] [Indexed: 11/23/2022]
Abstract
Unnatural combinations of polyketide synthase modules often fail to make a polyketide product. The causes of these failures are likely complex and are not yet amenable to rational correction. One possible explanation is the inability of the ketosynthase (KS) domain to extend the ketide donated to it by the upstream module. We therefore addressed the problem by exchanging KS domains of the acceptor module in a combinatorial fashion and coexpressing these chimeric modules with ketide-donor modules that naturally interact with the transplanted KS. This approach was remarkably successful in activating previously unproductive bimodular combinations, and the results augur well for the ongoing development of molecular tools to design and produce novel polyketides.
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Affiliation(s)
- Sunil S Chandran
- Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, California 94545, USA
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