1
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Diehl C, Gerlinger PD, Paczia N, Erb TJ. Synthetic anaplerotic modules for the direct synthesis of complex molecules from CO 2. Nat Chem Biol 2023; 19:168-175. [PMID: 36470994 PMCID: PMC9889269 DOI: 10.1038/s41589-022-01179-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 09/22/2022] [Indexed: 12/12/2022]
Abstract
Anaplerosis is an essential feature of metabolism that allows the continuous operation of natural metabolic networks, such as the citric acid cycle, by constantly replenishing drained intermediates. However, this concept has not been applied to synthetic in vitro metabolic networks, thus far. Here we used anaplerotic strategies to directly access the core sequence of the CETCH cycle, a new-to-nature in vitro CO2-fixation pathway that features several C3-C5 biosynthetic precursors. We drafted four different anaplerotic modules that use CO2 to replenish the CETCH cycle's intermediates and validated our designs by producing 6-deoxyerythronolide B (6-DEB), the C21-macrolide backbone of erythromycin. Our best design allowed the carbon-positive synthesis of 6-DEB via 54 enzymatic reactions in vitro at yields comparable to those with isolated 6-DEB polyketide synthase (DEBS). Our work showcases how new-to-nature anaplerotic modules can be designed and tailored to enhance and expand the synthetic capabilities of complex catalytic in vitro reaction networks.
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Affiliation(s)
- Christoph Diehl
- grid.419554.80000 0004 0491 8361Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Patrick D. Gerlinger
- grid.419554.80000 0004 0491 8361Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nicole Paczia
- grid.419554.80000 0004 0491 8361Core Facility for Metabolomics and Small Molecule Mass Spectrometry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Tobias J. Erb
- grid.419554.80000 0004 0491 8361Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany ,grid.452532.7SYNMIKRO Center for Synthetic Microbiology, Marburg, Germany
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2
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Properties and Mechanisms of Flavin-Dependent Monooxygenases and Their Applications in Natural Product Synthesis. Int J Mol Sci 2022; 23:ijms23052622. [PMID: 35269764 PMCID: PMC8910399 DOI: 10.3390/ijms23052622] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/21/2022] [Accepted: 02/25/2022] [Indexed: 11/17/2022] Open
Abstract
Natural products are usually highly complicated organic molecules with special scaffolds, and they are an important resource in medicine. Natural products with complicated structures are produced by enzymes, and this is still a challenging research field, its mechanisms requiring detailed methods for elucidation. Flavin adenine dinucleotide (FAD)-dependent monooxygenases (FMOs) catalyze many oxidation reactions with chemo-, regio-, and stereo-selectivity, and they are involved in the synthesis of many natural products. In this review, we introduce the mechanisms for different FMOs, with the classical FAD (C4a)-hydroperoxide as the major oxidant. We also summarize the difference between FMOs and cytochrome P450 (CYP450) monooxygenases emphasizing the advantages of FMOs and their specificity for substrates. Finally, we present examples of FMO-catalyzed synthesis of natural products. Based on these explanations, this review will expand our knowledge of FMOs as powerful enzymes, as well as implementation of the FMOs as effective tools for biosynthesis.
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3
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Pan L, Yang L, Huang Y, Liang Y, He Q, Yang D. Combinatorial Enzymatic Synthesis of Unnatural Long-Chain β-Branch Pyrones by a Highly Promiscuous Enzyme. ACS OMEGA 2019; 4:21078-21082. [PMID: 31867500 PMCID: PMC6921269 DOI: 10.1021/acsomega.9b02473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/21/2019] [Indexed: 06/10/2023]
Abstract
In this study, we described in detail a combinatorial enzymatic synthesis approach to produce a series of unnatural long-chain β-branch pyrones. We attempted to investigate the catalytic potential of a highly promiscuous enzyme type III PKS to catalyze the non-decarboxylative condensation reaction by two molecules of fatty acyl diketide-N-acetylcysteines (diketide-NACs) units. Two non-natural long-chain (C16, C18) fatty acyl diketide-NACs were prepared successfully for testing the ability of non-decarboxylative condensation. In vitro, 12 novel naturally unavailable long-chain β-branch pyrones were generated by one-pot formation and characterized by ultraviolet-visible spectroscopy and high-resolution liquid chromatography-mass spectrometry. Interestingly, enzymatic kinetics result displays that this enzyme exhibits the remarkable compatibility to various non-natural long-chain substrates. These results would be useful to deeply understand the catalytic mechanism of this enzyme and further extend the application of enzymatic synthesis of non-natural products.
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Affiliation(s)
- Lixia Pan
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
| | - Lilan Yang
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
| | - Yanbing Huang
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
| | - Yongyuan Liang
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
| | - Qihuan He
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
| | - Dengfeng Yang
- Guangxi
Key Laboratory of Biorefinery, Guangxi Biomass Industrialization
Engineering Institute, National Engineering Research Center of Non-food
Biorefinery, State Key Laboratory of Non-Food Biomass and Enzyme Technology and Guangxi Key Laboratory
of Marine Natural Products and Combinatorial Biosynthesis Chemistry,
Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, Guangxi, China
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4
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Hong M, Liao J, Chu J. High-throughput optimization of the chemically defined synthetic medium for the production of erythromycin A. Bioprocess Biosyst Eng 2018; 41:1529-1538. [PMID: 30003380 DOI: 10.1007/s00449-018-1980-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/06/2018] [Indexed: 11/28/2022]
Abstract
Erythromycin A is an important antibiotic. A chemically defined synthetic medium for erythromycin production was systematically optimized in this study. A high-throughput method was employed to reduce the number of components and optimize the concentration of each component. After two round single composition deletion experiment, only 19 components were remained in the medium, and then the concentration of each component was optimized through PB experiment. The optimal medium from the PB experiment was further optimized according to the nitrogen and phosphate metabolic consumption in 5 L bioreactor. It was observed that among the 8 amino acids concluded in the media, 4 amino acids were first consumed, when they are almost depleted, the other 4 amino acids were initiated their consumption afterwards in 5 L bioreactor. The decrease of phosphate concentration would increase qglc and qery. However, when phosphate concentration was too low, the production of erythromycin was hindered. The positive correlation between intracellular metabolite pools and Yery/glc indicated that low phosphate concentration in the medium can promote cell metabolism especially secondary metabolism during the stationary phase; however, if it was too low (5 mmol/L), the cell metabolism and secondary metabolism would both slow down. The erythromycin titer in the optimized medium (medium V) reached 1380 mg/L, which was 17 times higher than the previously used synthetic medium in our lab. The optimized medium can facilitate the metabolomics study or metabolic flux analysis of the erythromycin fermentation process, which laid a solid foundation for further study of erythromycin fermentation process.
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Affiliation(s)
- Ming Hong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Jianguo Liao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
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5
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Tsai SC(S. The Structural Enzymology of Iterative Aromatic Polyketide Synthases: A Critical Comparison with Fatty Acid Synthases. Annu Rev Biochem 2018; 87:503-531. [DOI: 10.1146/annurev-biochem-063011-164509] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polyketides are a large family of structurally complex natural products including compounds with important bioactivities. Polyketides are biosynthesized by polyketide synthases (PKSs), multienzyme complexes derived evolutionarily from fatty acid synthases (FASs). The focus of this review is to critically compare the properties of FASs with iterative aromatic PKSs, including type II PKSs and fungal type I nonreducing PKSs whose chemical logic is distinct from that of modular PKSs. This review focuses on structural and enzymological studies that reveal both similarities and striking differences between FASs and aromatic PKSs. The potential application of FAS and aromatic PKS structures for bioengineering future drugs and biofuels is highlighted.
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Affiliation(s)
- Shiou-Chuan (Sheryl) Tsai
- Departments of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical Sciences, University of California, Irvine, California 92697, USA
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6
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Weissman KJ. Polyketide stereocontrol: a study in chemical biology. Beilstein J Org Chem 2017; 13:348-371. [PMID: 28326145 PMCID: PMC5331325 DOI: 10.3762/bjoc.13.39] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/01/2017] [Indexed: 11/23/2022] Open
Abstract
The biosynthesis of reduced polyketides in bacteria by modular polyketide synthases (PKSs) proceeds with exquisite stereocontrol. As the stereochemistry is intimately linked to the strong bioactivity of these molecules, the origins of stereochemical control are of significant interest in attempts to create derivatives of these compounds by genetic engineering. In this review, we discuss the current state of knowledge regarding this key aspect of the biosynthetic pathways. Given that much of this information has been obtained using chemical biology tools, work in this area serves as a showcase for the power of this approach to provide answers to fundamental biological questions.
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Affiliation(s)
- Kira J Weissman
- UMR 7365, Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), CNRS-Université de Lorraine, Biopôle de l’Université de Lorraine, Campus Biologie Santé, Avenue de la Forêt de Haye, BP 50184, 54505 Vandœuvre-lès-Nancy Cedex, France
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7
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Robbins T, Liu YC, Cane DE, Khosla C. Structure and mechanism of assembly line polyketide synthases. Curr Opin Struct Biol 2016; 41:10-18. [PMID: 27266330 PMCID: PMC5136517 DOI: 10.1016/j.sbi.2016.05.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 11/16/2022]
Abstract
Assembly line polyketide synthases (PKSs) are remarkable biosynthetic machines with considerable potential for structure-based engineering. Several types of protein-protein interactions, both within and between PKS modules, play important roles in the catalytic cycle of a multimodular PKS. Additionally, vectorial biosynthesis is enabled by the energetic coupling of polyketide chain elongation to the channeling of intermediates between successive modules. A combination of high-resolution analysis of smaller PKS components and lower resolution characterization of intact modules and bimodules has yielded insights into the structure and organization of a prototypical assembly line PKS. This review discusses our understanding of key structure-function relationships in this family of megasynthases, along with a recap of key unanswered questions in the field.
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Affiliation(s)
- Thomas Robbins
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States
| | - Yu-Chen Liu
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States
| | - David E Cane
- Department of Chemistry, Brown University, Providence, RI 02912-9108, United States
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States.
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8
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Abstract
Synthetic biology (SB) is an emerging discipline, which is slowly reorienting the field of drug discovery. For thousands of years, living organisms such as plants were the major source of human medicines. The difficulty in resynthesizing natural products, however, often turned pharmaceutical industries away from this rich source for human medicine. More recently, progress on transformation through genetic manipulation of biosynthetic units in microorganisms has opened the possibility of in-depth exploration of the large chemical space of natural products derivatives. Success of SB in drug synthesis culminated with the bioproduction of artemisinin by microorganisms, a tour de force in protein and metabolic engineering. Today, synthetic cells are not only used as biofactories but also used as cell-based screening platforms for both target-based and phenotypic-based approaches. Engineered genetic circuits in synthetic cells are also used to decipher disease mechanisms or drug mechanism of actions and to study cell-cell communication within bacteria consortia. This review presents latest developments of SB in the field of drug discovery, including some challenging issues such as drug resistance and drug toxicity.
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Affiliation(s)
| | - Pablo Carbonell
- Faculty of Life Sciences, SYNBIOCHEM Centre, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
- Department of Experimental and Health Sciences (DCEXS), Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Barcelona, Spain
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9
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Ishikawa F, Suzuki T, Dohmae N, Kakeya H. A Multiple-Labeling Strategy for Nonribosomal Peptide Synthetases Using Active-Site-Directed Proteomic Probes for Adenylation Domains. Chembiochem 2015; 16:2590-4. [PMID: 26467472 DOI: 10.1002/cbic.201500481] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Indexed: 11/07/2022]
Abstract
Genetic approaches have greatly contributed to our understanding of nonribosomal peptide biosynthetic machinery; however, proteomic investigations are limited. Here, we developed a highly sensitive detection strategy for multidomain nonribosomal peptide synthetases (NRPSs) by using a multiple-labeling technique with active-site-directed probes for adenylation domains. When applied to gramicidin S-producing and -nonproducing strains of Aneurinibacillus migulanus (DSM 5759 and DSM 2895, respectively), the multiple technique sensitively detected an active multidomain NRPS (GrsB) in lysates obtained from the organisms. This functional proteomics method revealed an unknown inactive precursor (or other inactive form) of GrsB in the nonproducing strain. This method provides a new option for the direct detection, functional analysis, and high-resolution identification of low-abundance active NRPS enzymes in native proteomic environments.
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Affiliation(s)
- Fumihiro Ishikawa
- Department of System Chemotherapy and Molecular Sciences, Division of Bioinformatics and Chemical Genomics, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto, 606-8501, Japan.
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Hideaki Kakeya
- Department of System Chemotherapy and Molecular Sciences, Division of Bioinformatics and Chemical Genomics, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto, 606-8501, Japan.
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10
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The structural biology of biosynthetic megaenzymes. Nat Chem Biol 2015; 11:660-70. [PMID: 26284673 DOI: 10.1038/nchembio.1883] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/02/2015] [Indexed: 01/27/2023]
Abstract
The modular polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) are among the largest and most complicated enzymes in nature. In these biosynthetic systems, independently folding protein domains, which are organized into units called 'modules', operate in assembly-line fashion to construct polymeric chains and tailor their functionalities. Products of PKSs and NRPSs include a number of blockbuster medicines, and this has motivated researchers to understand how they operate so that they can be modified by genetic engineering. Beginning in the 1990s, structural biology has provided a number of key insights. The emerging picture is one of remarkable dynamics and conformational programming in which the chemical states of individual catalytic domains are communicated to the others, configuring the modules for the next stage in the biosynthesis. This unexpected level of complexity most likely accounts for the low success rate of empirical genetic engineering experiments and suggests ways forward for productive megaenzyme synthetic biology.
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11
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Davison J, Dorival J, Rabeharindranto H, Mazon H, Chagot B, Gruez A, Weissman KJ. Insights into the function of trans-acyl transferase polyketide synthases from the SAXS structure of a complete module. Chem Sci 2014. [DOI: 10.1039/c3sc53511h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Combined analysis by SAXS, NMR and homology modeling reveals the structure of an apo module from a trans-acyltransferase polyketide synthase.
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Affiliation(s)
- Jack Davison
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Jonathan Dorival
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Hery Rabeharindranto
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Hortense Mazon
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Benjamin Chagot
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Arnaud Gruez
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
| | - Kira J. Weissman
- Molecular and Structural Enzymology Group
- Université de Lorraine
- Vandœuvre-Lès-Nancy, France
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12
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Lowry B, Robbins T, Weng CH, O'Brien RV, Cane DE, Khosla C. In vitro reconstitution and analysis of the 6-deoxyerythronolide B synthase. J Am Chem Soc 2013; 135:16809-12. [PMID: 24161212 DOI: 10.1021/ja409048k] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Notwithstanding an extensive literature on assembly line polyketide synthases such as the 6-deoxyerythronolide B synthase (DEBS), a complete naturally occurring synthase has never been reconstituted in vitro from purified protein components. Here, we describe the fully reconstituted DEBS and quantitatively characterize some of the properties of the assembled system that have never been explored previously. The maximum turnover rate of the complete hexamodular system is 1.1 min(-1), comparable to the turnover rate of a truncated trimodular derivative (2.5 min(-1)) but slower than that of a bimodular derivative (21 min(-1)). In the presence of similar concentrations of methylmalonyl- and ethylmalonyl-CoA substrates, DEBS synthesizes multiple regiospecifically modified analogues, one of which we have analyzed in detail. Our studies lay the foundation for biochemically interrogating and rationally engineering polyketide assembly lines in an unprecedented manner.
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Affiliation(s)
- Brian Lowry
- Department of Chemical Engineering, ‡Department of Chemistry, §School of Medicine, and ⊥Medical Science Training Program, Stanford University , Stanford, California 94305, United States
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13
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Hansen DA, Rath CM, Eisman EB, Narayan ARH, Kittendorf JD, Mortison JD, Yoon YJ, Sherman DH. Biocatalytic synthesis of pikromycin, methymycin, neomethymycin, novamethymycin, and ketomethymycin. J Am Chem Soc 2013; 135:11232-8. [PMID: 23866020 DOI: 10.1021/ja404134f] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A biocatalytic platform that employs the final two monomodular type I polyketide synthases of the pikromycin pathway in vitro followed by direct appendage of D-desosamine and final C-H oxidation(s) in vivo was developed and applied toward the synthesis of a suite of 12- and 14-membered ring macrolide natural products. This methodology delivered both compound classes in 13 steps (longest linear sequence) from commercially available (R)-Roche ester in >10% overall yields.
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Affiliation(s)
- Douglas A Hansen
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
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14
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Cobb RE, Luo Y, Freestone T, Zhao H. Drug Discovery and Development via Synthetic Biology. Synth Biol (Oxf) 2013. [DOI: 10.1016/b978-0-12-394430-6.00010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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15
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Caffrey P. Dissecting complex polyketide biosynthesis. Comput Struct Biotechnol J 2012; 3:e201210010. [PMID: 24688670 PMCID: PMC3962154 DOI: 10.5936/csbj.201210010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 12/17/2022] Open
Abstract
Numerous bioactive natural products are synthesised by modular polyketide synthases. These compounds can be made in high yield by native multienzyme assembly lines. However, formation of analogues by genetically engineered systems is often considerably less efficient. Biochemical studies on intact polyketide synthase proteins have amassed a body of knowledge that is substantial but still incomplete. Recently, the constituent enzymes have been structurally characterised as discrete domains or didomains. These recombinant proteins have been used to reconstitute single extension cycles in vitro. This has given further insights into how the final stereochemistry of chiral centres in polyketides is determined. In addition, this approach has revealed how domains co-operate to ensure efficient transfer of growing intermediates along the assembly line. This work is leading towards more effective re-programming of these enzymes for use in synthesis of new medicinal compounds.
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Affiliation(s)
- Patrick Caffrey
- School of Biomolecular and Biomedical Science, Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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16
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Yan J, Hazzard C, Bonnett SA, Reynolds KA. Functional modular dissection of DEBS1-TE changes triketide lactone ratios and provides insight into Acyl group loading, hydrolysis, and ACP transfer. Biochemistry 2012; 51:9333-41. [PMID: 23116287 DOI: 10.1021/bi300830q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The DEBS1-TE fusion protein is comprised of the loading module, the first two extension modules, and the terminal TE domain of the Saccharopolyspora erythraea 6-deoxyerythronolide B synthase. DEBS1-TE produces triketide lactones that differ on the basis of the starter unit selected by the loading module. Typical fermentations with plasmid-based expression of DEBS1-TE produce a 6:1 ratio of propionate to isobutyrate-derived triketide lactones. Functional dissection of the loading module from the remainder of DEBS1-TE results in 50% lower titers of triketide lactone and a dramatic shift in the production to a 1:4 ratio of propionate to isobutyrate-derived products. A series of radiolabeling studies of the loading module has shown that transfer from the AT to the ACP occurs much faster for propionate than for isobutyrate. However, the equilibrium occupancy of the AT favors isobutyrate such that propionate is outcompeted for ACP occupancy. Thus, propionyl-ACP is the kinetic product, while isobutyryl-ACP is the thermodynamic product. A slowed transfer from the loading domain ACP to first-extension module KS due to functional dissection of DEBS1-TE allows this isobutyryl-ACP-favored equilibrium to be realized and likely accounts for the observed shift in triketide lactone products.
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Affiliation(s)
- John Yan
- Department of Chemistry, Portland State University, Portland, Oregon 97201, United States
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17
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Harvey CJB, Puglisi JD, Pande VS, Cane DE, Khosla C. Precursor directed biosynthesis of an orthogonally functional erythromycin analogue: selectivity in the ribosome macrolide binding pocket. J Am Chem Soc 2012; 134:12259-65. [PMID: 22741553 DOI: 10.1021/ja304682q] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The macrolide antibiotic erythromycin A and its semisynthetic analogues have been among the most useful antibacterial agents for the treatment of infectious diseases. Using a recently developed chemical genetic strategy for precursor-directed biosynthesis and colony bioassay of 6-deoxyerythromycin D analogues, we identified a new class of alkynyl- and alkenyl-substituted macrolides with activities comparable to that of the natural product. Further analysis revealed a marked and unexpected dependence of antibiotic activity on the size and degree of unsaturation of the precursor. Based on these leads, we also report the precursor-directed biosynthesis of 15-propargyl erythromycin A, a novel antibiotic that not only is as potent as erythromycin A with respect to its ability to inhibit bacterial growth and cell-free ribosomal protein biosynthesis but also harbors an orthogonal functional group that is capable of facile chemical modification.
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Affiliation(s)
- Colin J B Harvey
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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18
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Yu D, Xu F, Zeng J, Zhan J. Type III polyketide synthases in natural product biosynthesis. IUBMB Life 2012; 64:285-95. [DOI: 10.1002/iub.1005] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/28/2011] [Indexed: 11/08/2022]
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Kwan DH, Schulz F. The stereochemistry of complex polyketide biosynthesis by modular polyketide synthases. Molecules 2011; 16:6092-115. [PMID: 21775938 PMCID: PMC6264292 DOI: 10.3390/molecules16076092] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/06/2011] [Accepted: 07/18/2011] [Indexed: 11/24/2022] Open
Abstract
Polyketides are a diverse class of medically important natural products whose biosynthesis is catalysed by polyketide synthases (PKSs), in a fashion highly analogous to fatty acid biosynthesis. In modular PKSs, the polyketide chain is assembled by the successive condensation of activated carboxylic acid-derived units, where chain extension occurs with the intermediates remaining covalently bound to the enzyme, with the growing polyketide tethered to an acyl carrier domain (ACP). Carboxylated acyl-CoA precursors serve as activated donors that are selected by the acyltransferase domain (AT) providing extender units that are added to the growing chain by condensation catalysed by the ketosynthase domain (KS). The action of ketoreductase (KR), dehydratase (DH), and enoylreductase (ER) activities can result in unreduced, partially reduced, or fully reduced centres within the polyketide chain depending on which of these enzymes are present and active. The PKS-catalysed assembly process generates stereochemical diversity, because carbon–carbon double bonds may have either cis- or trans- geometry, and because of the chirality of centres bearing hydroxyl groups (where they are retained) and branching methyl groups (the latter arising from use of propionate extender units). This review shall cover the studies that have determined the stereochemistry in many of the reactions involved in polyketide biosynthesis by modular PKSs.
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Affiliation(s)
- David H. Kwan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver B.C., V6T 1Z1, Canada
- Authors to whom correspondence should be addressed; (D.H.K.); (F.S.); Tel.: +1-604-822-9300 (D.H.K.); +49-231-133-2429 (F.S.); Fax: +1-604-822-9126 (D.H.K.); +49-231-133-2498 (F.S.)
| | - Frank Schulz
- Fakultät für Chemie, Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44221 Dortmund, Germany
- Max-Planck-Institut für Molekulare Physiologie, Abteilung für Chemische Biologie, Otto-Hahn- Straße 11, 44227 Dortmund, Germany
- Authors to whom correspondence should be addressed; (D.H.K.); (F.S.); Tel.: +1-604-822-9300 (D.H.K.); +49-231-133-2429 (F.S.); Fax: +1-604-822-9126 (D.H.K.); +49-231-133-2498 (F.S.)
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Grindberg RV, Ishoey T, Brinza D, Esquenazi E, Coates RC, Liu WT, Gerwick L, Dorrestein PC, Pevzner P, Lasken R, Gerwick WH. Single cell genome amplification accelerates identification of the apratoxin biosynthetic pathway from a complex microbial assemblage. PLoS One 2011; 6:e18565. [PMID: 21533272 PMCID: PMC3075265 DOI: 10.1371/journal.pone.0018565] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 03/08/2011] [Indexed: 01/11/2023] Open
Abstract
Filamentous marine cyanobacteria are extraordinarily rich sources of structurally novel, biomedically relevant natural products. To understand their biosynthetic origins as well as produce increased supplies and analog molecules, access to the clustered biosynthetic genes that encode for the assembly enzymes is necessary. Complicating these efforts is the universal presence of heterotrophic bacteria in the cell wall and sheath material of cyanobacteria obtained from the environment and those grown in uni-cyanobacterial culture. Moreover, the high similarity in genetic elements across disparate secondary metabolite biosynthetic pathways renders imprecise current gene cluster targeting strategies and contributes sequence complexity resulting in partial genome coverage. Thus, it was necessary to use a dual-method approach of single-cell genomic sequencing based on multiple displacement amplification (MDA) and metagenomic library screening. Here, we report the identification of the putative apratoxin. A biosynthetic gene cluster, a potent cancer cell cytotoxin with promise for medicinal applications. The roughly 58 kb biosynthetic gene cluster is composed of 12 open reading frames and has a type I modular mixed polyketide synthase/nonribosomal peptide synthetase (PKS/NRPS) organization and features loading and off-loading domain architecture never previously described. Moreover, this work represents the first successful isolation of a complete biosynthetic gene cluster from Lyngbya bouillonii, a tropical marine cyanobacterium renowned for its production of diverse bioactive secondary metabolites.
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Affiliation(s)
- Rashel V. Grindberg
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
| | - Thomas Ishoey
- J. Craig Venter Institute, San Diego, California, United States of America
| | - Dumitru Brinza
- Department of Computer Science and Engineering, Center for Algorithmic and Systems Biology, University of California San Diego, La Jolla, California, United States of America
| | - Eduardo Esquenazi
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
| | - R. Cameron Coates
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
| | - Wei-ting Liu
- Departments of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
| | - Pieter C. Dorrestein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- Departments of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America
| | - Pavel Pevzner
- Department of Computer Science and Engineering, Center for Algorithmic and Systems Biology, University of California San Diego, La Jolla, California, United States of America
| | - Roger Lasken
- J. Craig Venter Institute, San Diego, California, United States of America
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Cane DE. Programming of erythromycin biosynthesis by a modular polyketide synthase. J Biol Chem 2010; 285:27517-23. [PMID: 20522551 DOI: 10.1074/jbc.r110.144618] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- David E Cane
- Department of Chemistry, Brown University, Providence, Rhode Island 02912-9108, USA.
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Tosin M, Betancor L, Stephens E, Ariel Li WM, Spencer JB, Leadlay PF. Synthetic Chain Terminators Off-Load Intermediates from a Type I Polyketide Synthase. Chembiochem 2010; 11:539-46. [DOI: 10.1002/cbic.200900772] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Valenzano CR, Lawson RJ, Chen AY, Khosla C, Cane DE. The biochemical basis for stereochemical control in polyketide biosynthesis. J Am Chem Soc 2009; 131:18501-11. [PMID: 19928853 PMCID: PMC3699857 DOI: 10.1021/ja908296m] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the most striking features of complex polyketides is the presence of numerous methyl- and hydroxyl-bearing stereogenic centers. To investigate the biochemical basis for the control of polyketide stereochemistry and to establish the timing and mechanism of the epimerization at methyl-bearing centers, a series of incubations was carried out using reconstituted components from a variety of modular polyketide synthases. In all cases the stereochemistry of the product was directly correlated with the intrinsic stereospecificity of the ketoreductase domain, independent of the particular chain elongation domains that were used, thereby establishing that methyl group epimerization, when it does occur, takes place after ketosynthase-catalyzed chain elongation. The finding that there were only minor differences in the rates of product formation observed for parallel incubations using an epimerizing ketoreductase domain and the nonepimerizing ketoreductase domain supports the proposal that the epimerization is catalyzed by the ketoreductase domain itself.
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Affiliation(s)
- Chiara R. Valenzano
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108
| | - Rachel J. Lawson
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108
| | - Alice Y. Chen
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
- Department of Chemistry, Stanford University, Stanford, California 94305
- Department of Biochemistry, Stanford University, Stanford, California 94305
| | - David E. Cane
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108
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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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Abstract
This review covers the biosynthesis of extender units that are utilized for the assembly of polyketides by polyketide synthases. The metabolic origins of each of the currently known polyketide synthase extender units are covered.
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Affiliation(s)
- Yolande A. Chan
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, WI 53706, USA
| | - Angela M. Podevels
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian M. Kevany
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael G. Thomas
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, WI 53706, USA
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27
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Chopra T, Banerjee S, Gupta S, Yadav G, Anand S, Surolia A, Roy RP, Mohanty D, Gokhale RS. Novel intermolecular iterative mechanism for biosynthesis of mycoketide catalyzed by a bimodular polyketide synthase. PLoS Biol 2008; 6:e163. [PMID: 18613748 PMCID: PMC2443190 DOI: 10.1371/journal.pbio.0060163] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Accepted: 05/27/2008] [Indexed: 11/18/2022] Open
Abstract
In recent years, remarkable versatility of polyketide synthases (PKSs) has been recognized; both in terms of their structural and functional organization as well as their ability to produce compounds other than typical secondary metabolites. Multifunctional Type I PKSs catalyze the biosynthesis of polyketide products by either using the same active sites repetitively (iterative) or by using these catalytic domains only once (modular) during the entire biosynthetic process. The largest open reading frame in Mycobacterium tuberculosis, pks12, was recently proposed to be involved in the biosynthesis of mannosyl-β-1-phosphomycoketide (MPM). The PKS12 protein contains two complete sets of modules and has been suggested to synthesize mycoketide by five alternating condensations of methylmalonyl and malonyl units by using an iterative mode of catalysis. The bimodular iterative catalysis would require transfer of intermediate chains from acyl carrier protein domain of module 2 to ketosynthase domain of module 1. Such bimodular iterations during PKS biosynthesis have not been characterized and appear unlikely based on recent understanding of the three-dimensional organization of these proteins. Moreover, all known examples of iterative PKSs so far characterized involve unimodular iterations. Based on cell-free reconstitution of PKS12 enzymatic machinery, in this study, we provide the first evidence for a novel “modularly iterative” mechanism of biosynthesis. By combination of biochemical, computational, mutagenic, analytical ultracentrifugation and atomic force microscopy studies, we propose that PKS12 protein is organized as a large supramolecular assembly mediated through specific interactions between the C- and N-terminus linkers. PKS12 protein thus forms a modular assembly to perform repetitive condensations analogous to iterative proteins. This novel intermolecular iterative biosynthetic mechanism provides new perspective to our understanding of polyketide biosynthetic machinery and also suggests new ways to engineer polyketide metabolites. The characterization of novel molecular mechanisms involved in biosynthesis of mycobacterial virulent lipids has opened new avenues for drug discovery. Polyketide synthases (PKSs) form a large family of multifunctional proteins involved in the biosynthesis of diverse classes of natural products. Mycobacterium tuberculosis (Mtb) exploits these polyketide biosynthetic enzymes to synthesize complex lipids, many of which are essential for its virulence. PKSs utilize two common mechanistic themes to produce these metabolites: (1) modular—in which each set of catalytic sites is used only once during the entire biosynthetic process and (2) iterative—in which the same set of active sites is used repeatedly. Our study with PKS12 protein from Mtb (the largest protein in this genome) reveals a third mechanism for polyketide biosynthesis. In this hybrid “modularly iterative” mechanism, PKS12 protein forms a supramolecular assembly to perform repetitive cycles of iterations. The protein assembly is formed by specific intermolecular interactions between N- and C-terminus linkers, analogous to modular PKSs. Our study adds a new dimension to the existing catalytic and mechanistic versatility of PKSs, providing a new perspective on how metabolic diversity could be generated by different combinations of existing functional scaffolds. A novel iterative biosynthetic mechanism for multifunctional polyketide synthases reveals how the metabolic diversity of this enzyme family can arise by using existing scaffolds in novel combinations.
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Affiliation(s)
- Tarun Chopra
- National Institute of Immunology, New Delhi, India
| | | | - Sarika Gupta
- National Institute of Immunology, New Delhi, India
| | | | - Swadha Anand
- National Institute of Immunology, New Delhi, India
| | | | | | | | - Rajesh S Gokhale
- National Institute of Immunology, New Delhi, India
- * To whom correspondence should be addressed. E-mail:
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Weissman KJ, Müller R. Protein–Protein Interactions in Multienzyme Megasynthetases. Chembiochem 2008; 9:826-48. [DOI: 10.1002/cbic.200700751] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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29
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Schell U, Haydock SF, Kaja AL, Carletti I, Lill RE, Read E, Sheehan LS, Low L, Fernandez MJ, Grolle F, McArthur HAI, Sheridan RM, Leadlay PF, Wilkinson B, Gaisser S. Engineered biosynthesis of hybrid macrolide polyketides containing d-angolosamine and d-mycaminose moieties. Org Biomol Chem 2008; 6:3315-27. [DOI: 10.1039/b807914e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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30
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Hopwood DA, Khosla C. Genes for polyketide secondary metabolic pathways in microorganisms and plants. CIBA FOUNDATION SYMPOSIUM 2007; 171:88-106; discussion 106-12. [PMID: 1302187 DOI: 10.1002/9780470514344.ch6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent advances in molecular genetics have led to the isolation, sequencing and functional analysis of genes encoding synthases that catalyse the formation of several classes of polyketides. The structures of the genes and their protein products differ strikingly in the various examples. For Streptomyces aromatic polyketides, exemplified by granaticin and tetracenomycin, the synthases correspond to Type II (bacterial and plant) fatty acid synthases in consisting of distinct proteins for such processes as condensation, acyl carrier function and ketoreduction. In contrast, for actinomycete macrolides such as erythromycin, similar catalytic functions are performed by a set of multifunctional proteins resembling Type I (animal) fatty acid synthases, but with every step in chain-building being catalysed by a different enzymic domain. Penicillium patulum has a simple Type I synthase for 6-methylsalicylic acid. For plant chalcones and stilbenes, a single small polypeptide acts as a condensing enzyme for carbon chain-building and may be unrelated to any of the other polyketide and fatty acid synthases. Thus, although these systems share a common general mechanism of chain assembly, they must differ in the ways that synthase 'programming' has evolved to determine chain length, choice of chain starter and extender units, and handling of successive keto groups during chain assembly, and so control the great diversity of possible chemical products.
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Affiliation(s)
- D A Hopwood
- John Innes Institute, John Innes Centre, Norwich, UK
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31
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Gokhale RS, Saxena P, Chopra T, Mohanty D. Versatile polyketide enzymatic machinery for the biosynthesis of complex mycobacterial lipids. Nat Prod Rep 2007; 24:267-77. [PMID: 17389997 DOI: 10.1039/b616817p] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The cell envelope of Mycobacterium tuberculosis (Mtb) is a treasure house of a variety of biologically active molecules with fascinating architectures. The decoding of the genetic blueprint of Mtb in recent years has provided the impetus for dissecting the metabolic pathways involved in the biosynthesis of lipidic metabolites. The focus of the Highlight is to emphasize the functional role of polyketide synthase (PKS) proteins in the biosynthesis of complex mycobacterial lipids. The catalytic as well as mechanistic versatility of PKS. in generating metabolic diversity and the significance of recently discovered fatty acyl-AMP ligases in establishing "biochemical crosstalk" between fatty acid synthases (FASs) and PKSs is described. The phenotypic heterogeneity and remodeling of the mycobacterial cell wall in its aetiopathogenesis is discussed.
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Affiliation(s)
- Rajesh S Gokhale
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
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Lai JR, Koglin A, Walsh CT. Carrier protein structure and recognition in polyketide and nonribosomal peptide biosynthesis. Biochemistry 2007; 45:14869-79. [PMID: 17154525 DOI: 10.1021/bi061979p] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carrier proteins, 80-100 residues in length, serve as information-rich platforms to present growing acyl and peptidyl chains as covalently tethered phosphopantetheinyl-thioester intermediates during the biosynthesis of fatty acid, polyketide, and nonribosomal natural products. Carrier proteins are recognized both in cis and in trans by partner catalytic domains that effect chain-elongating condensations, redox adjustments, other tailoring steps, and finally kinetically controlled disconnection and release of the mature natural product. Dissection of regions of carrier proteins that are specifically recognized by upstream and downstream catalytic partner proteins is deciphering the logic for multiprotein assembly line construction of these large classes of natural products.
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Affiliation(s)
- Jonathan R Lai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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Deng Z, Bai L. Antibiotic biosynthetic pathways and pathway engineering--a growing research field in China. Nat Prod Rep 2006; 23:811-27. [PMID: 17003911 DOI: 10.1039/b611140h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review describes the recent research activities in China in relation to studies on antibiotic biosynthetic pathways and pathway engineering in actinomycetes. 75 references are cited.
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Affiliation(s)
- Zixin Deng
- Laboratory of Microbial Metabolism and School of Life Science & Biotechnology, Shanghai Jiaotong University, Shanghai, 200030, China.
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Chuck JA, Dunn C, Facultad FECD, Nakazono C, Nikodinovic J, Barrow KD. Amplification of DNA encoding entire type I polyketide synthase domains and linkers from streptomyces species. Curr Microbiol 2006; 53:89-94. [PMID: 16832727 DOI: 10.1007/s00284-005-0050-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Accepted: 05/13/2005] [Indexed: 11/26/2022]
Abstract
Polyketides are a group of bioactive compounds from bacteria, plants, and fungi. To increase the availability of analogs for testing, the active sites of polyketide synthases are often substituted with homologous domains having altered substrate specificities. This study reports the design of polymerase chain reaction primers that enables isolation of entire active site domains from type I polyketide synthases with native interdomain linkers. This bypasses the need for further genetic screening to obtain functional units for use in genetic engineering. This is especially important in bioprospecting projects exploring new environments for bioresources.
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Affiliation(s)
- Jo-Anne Chuck
- School of Natural Sciences, University of Western Sydney, Parramatta Campus, Locked Bag 1797, Penrith South, DC, 1797 NSW, Australia.
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Abstract
Polyketide natural products such as erythromycin and rapamycin are assembled on polyketide synthases (PKSs), which consist of modular sets of catalytic activities distributed across multiple protein subunits. Correct protein-protein interactions among the PKS subunits which are critical to the fidelity of biosynthesis are mediated in part by "docking domains" at the termini of the proteins. The NMR solution structure of a representative docking domain complex from the erythromycin PKS (DEBS) was recently solved, and on this basis it has been proposed that PKS docking is mediated by the formation of an intermolecular four-alpha-helix bundle. Herein, we report the genetic engineering of such a docking domain complex by replacement of specific helical segments and analysis of triketide synthesis by mutant PKSs in vivo. The results of these helix swaps are fully consistent with the model and highlight residues in the docking domains that may be targeted to alter the efficiency or specificity of subunit-subunit docking in hybrid PKSs.
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Affiliation(s)
- Kira J Weissman
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.
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36
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McLoughlin SM, Mazur MT, Miller LM, Yin J, Liu F, Walsh CT, Kelleher NL. Chemoenzymatic approaches for streamlined detection of active site modifications on thiotemplate assembly lines using mass spectrometry. Biochemistry 2006; 44:14159-69. [PMID: 16245932 DOI: 10.1021/bi051202g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For the direct interrogation of peptides harboring covalently modified serines in nonribosomal peptide synthetases, streamlined methodologies described here employ proteolysis and reporter-coenzyme A analogues of four types. The chromophoric and fluorescent coenzyme A analogues pyrene-maleimidyl-S-CoA and BODIPY-FL-N-(2-aminoethyl)maleimidyl-S-CoA were enzymatically loaded onto the active site serines harbored in the ArCP, PCP1, and PCP2 thiolation domains of PchE and PchF, the nonribosomal peptide synthetases responsible for the biosynthesis of the siderophore pyochelin. During the chromatographic separation of cyanogen bromide digests, observation of the absorbance (at 338 and 504 nm) or fluorescence (after irradiation at 365 nm) enabled the selective detection of peptides containing each active site serine. This resulted in quick detection of each active site peptide by Fourier transform mass spectrometry in the fully reconstituted pyochelin system. The loading of short acyl chain reporters in equimolar quantities permitted further insights into digestion heterogeneity and side reactions by virtue of a mass shift signature on each active site peptide. The chromatographic shift of the reporter-loaded peptides relative to peptides carrying on pathway intermediates was 2 min at 7 kDa, providing a general strategy for efficient localization of "carrier" peptides in complex digests of thiotemplate enzymes. Also, the use of the affinity reporter, biotin-maleimidyl-S-coenzyme A, permitted the isolation of intact synthetases at high purity via removal of contaminating Escherichia coli proteins.
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Affiliation(s)
- Shaun M McLoughlin
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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Dorrestein PC, Kelleher NL. Dissecting non-ribosomal and polyketide biosynthetic machineries using electrospray ionization Fourier-Transform mass spectrometry. Nat Prod Rep 2006; 23:893-918. [PMID: 17119639 DOI: 10.1039/b511400b] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Many virulence factors and bioactive compounds with antifungal, antimicrobial, and antitumor properties are produced via the non-ribosomal peptide synthetase (NRPS) or polyketide synthase(PKS) paradigm. During the biosynthesis of these natural products, substrates, intermediates and side products are covalently tethered to the NRPS or PKS catalyst, introducing mass changes, making these biosynthetic systems ideal candidates for interrogation by large molecule mass spectrometry. This review serves as an introduction into the application of electrospray ionization Fourier-Transform massspectrometry (ESI-FTMS) to investigate NRPS and PKS systems. ESI-FTMS can be used to understand substrate tolerance, timing of covalent linkages, timing of tailoring reactions and the transfer of substrates and biosynthetic intermediates from domain to domain. Therefore we not only highlight key mechanistic insights for thiotemplate systems as found on the enterobactin,yersiniabactin, epothilone, clorobiocin, coumermycin, pyoluteorin, gramicidin, mycosubtilin, C-1027,6-deoxyerythronolide B and FK520 biosynthetic pathways, but we also explain the approaches taken to identify active sites from complex digests and compare the FTMS based assay to traditional assays and other mass spectrometric techniques. Although mass spectrometry was introduced over two decades ago to investigate NRPS and PKS biosynthetic systems, this is the first review devoted to this methodology.
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Affiliation(s)
- Pieter C Dorrestein
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Boakes S, Oliynyk M, Cortés J, Böhm I, Rudd BAM, Revill WP, Staunton J, Leadlay PF. A New Modular Polyketide Synthase in the Erythromycin Producer Saccharopolyspora erythraea. J Mol Microbiol Biotechnol 2005; 8:73-80. [PMID: 15925898 DOI: 10.1159/000084562] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A previously unidentified set of genes encoding a modular polyketide synthase (PKS) has been sequenced in Saccharopolyspora erythraea, producer of the antibiotic erythromycin. This new PKS gene cluster (pke) contains four adjacent large open reading frames (ORFs) encoding eight extension modules, flanked by a number of other ORFs which can be plausibly assigned roles in polyketide biosynthesis. Disruption of the pke PKS genes gave S. erythraea mutant JC2::pSBKS6, whose growth characteristics and pattern of secondary metabolite production did not apparently differ from the parent strain under any of the growth conditions tested. However, the pke PKS loading module and individual pke acyltransferase domains were shown to be active when used in engineered hybrid PKSs, making it highly likely that under appropriate conditions these biosynthetic genes are indeed expressed and active, and synthesize a novel polyketide product.
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Affiliation(s)
- Steven Boakes
- Cambridge Centre for Molecular Recognition and Department of Biochemistry, University of Cambridge, Cambridge, UK
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Weissman KJ. Polyketide synthases: mechanisms and models. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2005:43-78. [PMID: 15645716 DOI: 10.1007/3-540-27055-8_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Affiliation(s)
- K J Weissman
- Department of Biochemistry, University of Cambridge, UK.
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40
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Abstract
A novel fluorinated erythromycin (16-fluoroerythromycin A) has been produced by Saccharopolyspora erythraea ERMD1, using precursor-directed biosynthesis.
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Affiliation(s)
- Rebecca J M Goss
- Department of Chemistry, University of Exeter, Exeter, Devon, UK EX4 4QD.
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41
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Weissman KJ. Polyketide biosynthesis: understanding and exploiting modularity. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2004; 362:2671-2690. [PMID: 15539364 DOI: 10.1098/rsta.2004.1470] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polyketide-based pharmaceuticals are some of our most important medicines. They are constructed in micro-organisms (typically bacteria and fungi) by gigantic enzyme catalysts called polyketide synthases (PKSs). The organization of PKSs into molecular assembly lines makes them particularly appealing targets for genetic engineering because, in principle, an alteration in the enzyme organization might translate into a predictable change in polyketide structure. Excitingly, this has been shown repeatedly to work in practice, but the efficiency of the engineered PKSs is frequently too low to be useful for large-scale drug synthesis. To reach this goal, researchers need a deeper understanding of the structure and function of these proteins, which are among the most complex in nature. This review highlights some recent experiments which are providing key information about the molecular organization, mechanism and orchestration of these magnificent catalysts, and opening up fresh prospects of truly combinatorial biosynthesis of novel polyketides as leads in drug discovery.
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Affiliation(s)
- Kira J Weissman
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.
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42
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La Clair JJ, Foley TL, Schegg TR, Regan CM, Burkart MD. Manipulation of carrier proteins in antibiotic biosynthesis. ACTA ACUST UNITED AC 2004; 11:195-201. [PMID: 15123281 DOI: 10.1016/j.chembiol.2004.02.010] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2003] [Revised: 11/05/2003] [Accepted: 11/17/2003] [Indexed: 10/21/2022]
Abstract
Engineering biosynthetic pathways into suitable host organisms has become an attractive venue for the design, evaluation, and production of small molecule therapeutics. Polyketide (PK) and nonribosomal peptide (NRP) synthases have been of particular interest due to their modular structure, yet routine cloning and expression of these enzymes remains challenging. Here we describe a method to covalently label carrier proteins from PK and NRP synthases using the enzymatic transfer of a modified coenzyme A analog by a 4'-phosphopantetheinyltransferase. Using this method, carrier proteins can be loaded with single fluorescent or affinity reporters, providing novel entry for protein visualization, Western blot identification, and affinity purification. Application of these methods provides an ideal tool to track and quantify metabolically engineered pathways. Such techniques are valuable to measure protein expression, solubility, activity, and native posttranslational modification events in heterologous systems.
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Affiliation(s)
- James J La Clair
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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43
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Lum AM, Huang J, Hutchinson CR, Kao CM. Reverse engineering of industrial pharmaceutical-producing actinomycete strains using DNA microarrays. Metab Eng 2004; 6:186-96. [PMID: 15256208 DOI: 10.1016/j.ymben.2003.12.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 12/17/2003] [Indexed: 11/23/2022]
Abstract
Transcript levels in production cultures of wildtype and classically improved strains of the actinomycete bacteria Saccharopolyspora erythraea and Streptomyces fradiae were monitored using microarrays of the sequenced actinomycete S. coelicolor. Sac. erythraea and S. fradiae synthesize the polyketide antibiotics erythromycin and tylosin, respectively, and the classically improved strains contain unknown overproduction mutations. The Sac. erythraea overproducer was found to express the entire 56-kb erythromycin gene cluster several days longer than the wildtype strain. In contrast, the S. fradiae wildtype and overproducer strains expressed the 85-kb tylosin biosynthetic gene cluster similarly, while they expressed several tens of other S. fradiae genes and S. coelicolor homologs differently, including the acyl-CoA dehydrogenase gene aco and the S. coelicolor isobutyryl-CoA mutase homolog icmA. These observations indicated that overproduction mechanisms in classically improved strains can affect both the timing and rate of antibiotic synthesis, and alter the regulation of antibiotic biosynthetic enzymes and enzymes involved in precursor metabolism.
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Affiliation(s)
- Amy M Lum
- Department of Chemical Engineering, MC 5025, Stanford University, CA 94305, USA
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44
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Broadhurst RW, Nietlispach D, Wheatcroft MP, Leadlay PF, Weissman KJ. The structure of docking domains in modular polyketide synthases. CHEMISTRY & BIOLOGY 2003; 10:723-31. [PMID: 12954331 DOI: 10.1016/s1074-5521(03)00156-x] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Polyketides from actinomycete bacteria provide the basis for many valuable medicines, so engineering genes for their biosynthesis to produce variant molecules holds promise for drug discovery. The modular polyketide synthases are particularly amenable to this approach, because each cycle of chain extension is catalyzed by a different module of enzymes, and the modules are arranged within giant multienzyme subunits in the order in which they act. Protein-protein interactions between terminal docking domains of successive multienzymes promote their correct positioning within the assembly line, but because the overall complex is not stable in vitro, the key interactions have not been identified. We present here the NMR solution structure of a 120 residue polypeptide representing a typical pair of such domains, fused at their respective C and N termini: it adopts a stable dimeric structure which reveals the detailed role of these (predominantly helical) domains in docking and dimerization by modular polyketide synthases.
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Affiliation(s)
- R William Broadhurst
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA, Cambridge, United Kingdom
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45
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Hu Z, Pfeifer BA, Chao E, Murli S, Kealey J, Carney JR, Ashley G, Khosla C, Hutchinson CR. A specific role of the Saccharopolyspora erythraea thioesterase II gene in the function of modular polyketide synthases. MICROBIOLOGY (READING, ENGLAND) 2003; 149:2213-2225. [PMID: 12904561 DOI: 10.1099/mic.0.26015-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial modular polyketide synthase (PKS) genes are commonly associated with another gene that encodes a thioesterase II (TEII) believed to remove aberrantly loaded substrates from the PKS. Co-expression of the Saccharopolyspora erythraea ery-ORF5 TEII and eryA genes encoding 6-deoxyerythronolide B synthase (DEBS) in Streptomyces hosts eliminated or significantly lowered production of 8,8'-deoxyoleandolide [15-nor-6-deoxyerythronolide B (15-nor-6dEB)], which arises from an acetate instead of a propionate starter unit. Disruption of the TEII gene in an industrial Sac. erythraea strain caused a notable amount of 15-norerythromycins to be produced by utilization of an acetate instead of a propionate starter unit and also resulted in moderately lowered production of erythromycin compared with the amount produced by the parental strain. A similar behaviour of the TEII gene was observed in Escherichia coli strains that produce 6dEB and 15-methyl-6dEB. Direct biochemical analysis showed that the ery-ORF5 TEII enzyme favours hydrolysis of acetyl groups bound to the loading acyl carrier protein domain (ACP(L)) of DEBS. These results point to a clear role of the TEII enzyme, i.e. removal of a specific type of acyl group from the ACP(L) domain of the DEBS1 loading module.
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Affiliation(s)
- Zhihao Hu
- Kosan Biosciences, Hayward, CA 94545, USA
| | - Blaine A Pfeifer
- Department of Chemical Engineering, Chemistry and Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Elizabeth Chao
- Department of Chemical Engineering, Chemistry and Biochemistry, Stanford University, Stanford, CA 94305, USA
| | | | - Jim Kealey
- Kosan Biosciences, Hayward, CA 94545, USA
| | | | | | - Chaitan Khosla
- Department of Chemical Engineering, Chemistry and Biochemistry, Stanford University, Stanford, CA 94305, USA
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46
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Cropp TA, Kim BS, Beck BJ, Yoon YJ, Sherman DH, Reynolds KA. Recent developments in the production of novel polyketides by combinatorial biosynthesis. Biotechnol Genet Eng Rev 2003; 19:159-72. [PMID: 12520877 DOI: 10.1080/02648725.2002.10648028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- T Ashton Cropp
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23219, USA
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47
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Gaisser S, Lill R, Staunton J, Méndez C, Salas J, Leadlay PF. Parallel pathways for oxidation of 14-membered polyketide macrolactones in Saccharopolyspora erythraea. Mol Microbiol 2002; 44:771-81. [PMID: 11994157 DOI: 10.1046/j.1365-2958.2002.02910.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The glycosyltransferases OleG1 and OleG2 and the cytochrome P450 oxidase OleP from the oleandomycin biosynthetic gene cluster of Streptomyces antibioticus have been expressed, either separately or from artificial gene cassettes, in strains of Saccharopolyspora erythraea blocked in erythromycin biosynthesis, to investigate their potential for the production of diverse novel macrolides from erythronolide precursors. OleP was found to oxidize 6-deoxyerythronolide B, but not erythronolide B. However, OleP did oxidize derivatives of erythronolide B in which a neutral sugar is attached at C-3. The oxidized products 3-O-mycarosyl-8a-hydroxyerythronolide B, 3-O-mycarosyl-8,8a-epoxyerythronolide B, 6-deoxy-8-hydroxyerythronolide B and the olefin 6-deoxy-8,8a-dehydroerythronolide B were all isolated and their structures determined. When oleP and the mycarosyltransferase eryBV were co-expressed in a gene cassette, 3-O-mycarosyl-6-deoxy-8,8a-dihydroxyerythronolide B was directly obtained. When oleG2 was co-expressed in a gene cassette together with oleP, 6-deoxyerythronolide B was converted into a mixture of 3-O-rhamnosyl-6-deoxy-8,8a-dehydroerythronolide B and 3-O-rhamnosyl-6-deoxy-8,8a-dihydroxyerythronolide B, confirming previous reports that OleG2 can transfer rhamnose, and confirming that oxidation by OleP and attachment of the neutral sugar to the aglycone can occur in either order. Similarly, four different 3-O-mycarosylerythronolides were found to be substrates for the desosaminyltransferase OleG1. These results provide additional insight into the nature of the intermediates in OleP-mediated oxidation, and suggest that oleandomycin biosynthesis might follow parallel pathways in which epoxidation either precedes or follows attachment of the neutral sugar.
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48
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Long PF, Wilkinson CJ, Bisang CP, Cortés J, Dunster N, Oliynyk M, McCormick E, McArthur H, Mendez C, Salas JA, Staunton J, Leadlay PF. Engineering specificity of starter unit selection by the erythromycin-producing polyketide synthase. Mol Microbiol 2002; 43:1215-25. [PMID: 11918808 DOI: 10.1046/j.1365-2958.2002.02815.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chain initiation on many modular polyketide synthases is mediated by acyl transfer from the CoA ester of a dicarboxylic acid, followed by decarboxylation in situ by KSQ, a ketosynthase-like decarboxylase domain. Consistent with this, the acyltransferase (AT) domains of all KSQ-containing loading modules are shown here to contain a key arginine residue at their active site. Site-specific replacement of this arginine residue in the oleandomycin (ole) loading AT domain effectively abolished AT activity, consistent with its importance for catalysis. Substitution of the ole PKS loading module, or of the tylosin PKS loading module, for the erythromycin (ery) loading module gave polyketide products almost wholly either acetate derived or propionate derived, respectively, instead of the mixture found normally. An authentic extension module AT domain, rap AT2 from the rapamycin PKS, functioned appropriately when engineered in the place of the ole loading AT domain, and gave rise to substantial amounts of C13-methylerythromycins, as predicted. The role of direct acylation of the ketosynthase domain of ex-tension module 1 in chain initiation was confirmed by demonstrating that a mutant of the triketide synthase DEBS1-TE, in which the 4'-phosphopante-theine attachment site for starter acyl groups was specifically removed, produced triketide lactone pro-ducts in detectable amounts.
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Affiliation(s)
- Paul F Long
- Cambridge Centre for Molecular Recognition and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
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49
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Østergaard LH, Kellenberger L, Cortés J, Roddis MP, Deacon M, Staunton J, Leadlay PF. Stereochemistry of catalysis by the ketoreductase activity in the first extension module of the erythromycin polyketide synthase. Biochemistry 2002; 41:2719-26. [PMID: 11851419 DOI: 10.1021/bi0117605] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multiple ketoreductase activities play a crucial role in establishing the stereochemistry of the products of modular polyketide synthases (PKSs), but there has been little systematic scrutiny of catalysis by individual ketoreductases. To allow this, a diketide synthase, consisting of the loading module, first extension module, and the chain-terminating thioesterase of the erythromycin-producing PKS of Saccharopolyspora erythraea, has been expressed and purified. The DNA encoding the ketoreductase-1 domain in this construct is flanked by unique restriction sites so that another ketoreductase domain can be readily substituted. The purified recombinant diketide synthase catalyzes, at a very low rate (k(cat) equals 2.5 x 10(-3) s(-1)), the specific production of the diketide (2S,3R)-2-methyl-3-hydroxypentanoic acid. The activity of the ketoreductase domain in this model synthase was analyzed using as a model substrate (+/-)-2-methyl-3-oxopentanoic acid N-acetylcysteaminyl (NAC) ester for which k(cat)/K(m) was 21.7 M(-1) s(-1). The NAC thioester of (2S,3R)-2-methyl-3-hydroxypentanoic acid was the major product and was strongly preferred over other stereoisomers as a substrate in the reverse reaction. The bicyclic ketone (9RS)-trans-1-decalone, a known substrate for ketoreductase in fatty acid synthase, was found also to be an effective substrate for the ketoreductase of the diketide synthase. Only the (9R)-trans-1-decalone was reduced, selectively and reversibly, to the (1S,9R)-trans-decalol. The stereochemical course of reduction and oxidation is exactly as found previously for the ketoreductase of animal fatty acid synthase, an additional indication of the close similarity of these enzymes.
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Affiliation(s)
- Lars H Østergaard
- Cambridge Centre for Molecular Recognition and Departments of Biochemistry and Chemistry, University of Cambridge, Cambridge, U.K
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50
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Abstract
A plethora of human pathogens are now resistant to all clinically significant antibiotics causing a crisis, in the treatment and management of infectious diseases, but also presenting a clear danger to future public health. If drug resistance is going to be tackled successfully, new antibiotics must be continually developed to counteract the processes of evolution and natural selection in these populations of pathogens. Despite the introduction of powerful new technologies such as high throughput screening platforms and combinatorial chemistry, natural products still offer structural diversity worthy of screening for biological activity. Functional genomics can revolutionise rational drug design providing new targets for antimicrobial drug discovery. The clusters of genes, encoding enzymes that form bio-synthetic pathways leading to the synthesis of many natural products including polyketides and non-ribosomal peptides, are amenable to modern genetic engineering. Repositioning, deleting and replacing genes in these biosynthetic clusters has resulted in the synthesis of many 'un-natural' natural products. This review examines the engineering of proteins involved in chain initiation on polyketide synthases culminating in the production at high yield of a biologically active erythromycin derivative.
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Affiliation(s)
- Alastair C.W. Waugh
- Leeds University College, London. Eastman Dental Institute culminating. University of London School of Pharmacy
| | - Paul F. Long
- Pharmaceutical Microbiology at the University of London School of Pharmacy, 29/39 Brunswick Square, London WC1N 1AX. Cambridge University. University of Wisconsin-Madison
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