1
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Li F, Lin Z, Torres JP, Hill EA, Li D, Townsend CA, Schmidt EW. Sea Urchin Polyketide Synthase SpPks1 Produces the Naphthalene Precursor to Echinoderm Pigments. J Am Chem Soc 2022; 144:9363-9371. [PMID: 35588530 DOI: 10.1021/jacs.2c01416] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nearly every animal species on Earth contains a unique polyketide synthase (PKS) encoded in its genome, yet no animal-clade PKS has been biochemically characterized, and even the chemical products of these ubiquitous enzymes are known in only a few cases. The earliest animal genome-encoded PKS gene to be identified was SpPks1 from sea urchins. Previous genetic knockdown experiments implicated SpPks1 in synthesis of the sea urchin pigment echinochrome. Here, we express and purify SpPks1, performing biochemical experiments to demonstrate that the sea urchin protein is responsible for the synthesis of 2-acetyl-1,3,6,8-tetrahydroxynaphthalene (ATHN). Since ATHN is a plausible precursor of echinochromes, this result defines a biosynthetic pathway to the ubiquitous echinoderm pigments and rewrites the previous hypothesis for echinochrome biosynthesis. Truncation experiments showed that, unlike other type I iterative PKSs so far characterized, SpPks1 produces the naphthalene core using solely ketoacylsynthase (KS), acyltransferase, and acyl carrier protein domains, delineating a unique class of animal nonreducing aromatic PKSs (aPKSs). A series of amino acids in the KS domain define the family and are likely crucial in cyclization activity. Phylogenetic analyses indicate that SpPks1 and its homologs are widespread in echinoderms and their closest relatives, the acorn worms, reinforcing their fundamental importance to echinoderm biology. While the animal microbiome is known to produce aromatic polyketides, this work provides biochemical evidence that animals themselves also harbor ancient, convergent, dedicated pathways to carbocyclic aromatic polyketides. More fundamentally, biochemical analysis of SpPks1 begins to define the vast and unexplored biosynthetic space of the ubiquitous animal PKS family.
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Affiliation(s)
- Feng Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, P. R. China.,Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Zhenjian Lin
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Joshua P Torres
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Eric A Hill
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Dehai Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, P. R. China
| | - Craig A Townsend
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Eric W Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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2
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Paiva P, Medina FE, Viegas M, Ferreira P, Neves RPP, Sousa JPM, Ramos MJ, Fernandes PA. Animal Fatty Acid Synthase: A Chemical Nanofactory. Chem Rev 2021; 121:9502-9553. [PMID: 34156235 DOI: 10.1021/acs.chemrev.1c00147] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fatty acids are crucial molecules for most living beings, very well spread and conserved across species. These molecules play a role in energy storage, cell membrane architecture, and cell signaling, the latter through their derivative metabolites. De novo synthesis of fatty acids is a complex chemical process that can be achieved either by a metabolic pathway built by a sequence of individual enzymes, such as in most bacteria, or by a single, large multi-enzyme, which incorporates all the chemical capabilities of the metabolic pathway, such as in animals and fungi, and in some bacteria. Here we focus on the multi-enzymes, specifically in the animal fatty acid synthase (FAS). We start by providing a historical overview of this vast field of research. We follow by describing the extraordinary architecture of animal FAS, a homodimeric multi-enzyme with seven different active sites per dimer, including a carrier protein that carries the intermediates from one active site to the next. We then delve into this multi-enzyme's detailed chemistry and critically discuss the current knowledge on the chemical mechanism of each of the steps necessary to synthesize a single fatty acid molecule with atomic detail. In line with this, we discuss the potential and achieved FAS applications in biotechnology, as biosynthetic machines, and compare them with their homologous polyketide synthases, which are also finding wide applications in the same field. Finally, we discuss some open questions on the architecture of FAS, such as their peculiar substrate-shuttling arm, and describe possible reasons for the emergence of large megasynthases during evolution, questions that have fascinated biochemists from long ago but are still far from answered and understood.
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Affiliation(s)
- Pedro Paiva
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Fabiola E Medina
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Autopista Concepción-Talcahuano, 7100 Talcahuano, Chile
| | - Matilde Viegas
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Pedro Ferreira
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Rui P P Neves
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - João P M Sousa
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Maria J Ramos
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Pedro A Fernandes
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
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3
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Sulpizio A, Crawford CEW, Koweek RS, Charkoudian LK. Probing the structure and function of acyl carrier proteins to unlock the strategic redesign of type II polyketide biosynthetic pathways. J Biol Chem 2021; 296:100328. [PMID: 33493513 PMCID: PMC7949117 DOI: 10.1016/j.jbc.2021.100328] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 02/04/2023] Open
Abstract
Type II polyketide synthases (PKSs) are protein assemblies, encoded by biosynthetic gene clusters in microorganisms, that manufacture structurally complex and pharmacologically relevant molecules. Acyl carrier proteins (ACPs) play a central role in biosynthesis by shuttling malonyl-based building blocks and polyketide intermediates to catalytic partners for chemical transformations. Because ACPs serve as central hubs in type II PKSs, they can also represent roadblocks to successfully engineering synthases capable of manufacturing 'unnatural natural products.' Therefore, understanding ACP conformational dynamics and protein interactions is essential to enable the strategic redesign of type II PKSs. However, the inherent flexibility and transience of ACP interactions pose challenges to gaining insight into ACP structure and function. In this review, we summarize how the application of chemical probes and molecular dynamic simulations has increased our understanding of the structure and function of type II PKS ACPs. We also share how integrating these advances in type II PKS ACP research with newfound access to key enzyme partners, such as the ketosynthase-chain length factor, sets the stage to unlock new biosynthetic potential.
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Affiliation(s)
- Ariana Sulpizio
- Department of Chemistry, Haverford College, Haverford, Pennsylvania, USA
| | | | - Rebecca S Koweek
- Department of Chemistry, Haverford College, Haverford, Pennsylvania, USA
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4
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Deng Z, Liu J, Li T, Li H, Liu Z, Dong Y, Li W. An Unusual Type II Polyketide Synthase System Involved in Cinnamoyl Lipid Biosynthesis. Angew Chem Int Ed Engl 2020; 60:153-158. [PMID: 32860295 DOI: 10.1002/anie.202007777] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/13/2020] [Indexed: 12/13/2022]
Abstract
As a unique structural moiety in natural products, cinnamoyl lipids (CLs), are proposed to be assembled by unusual type II polyketide synthases (PKSs). Herein, we demonstrate that the assembly of the CL compounds youssoufenes is accomplished by a PKS system that uniquely harbors three phylogenetically different ketosynthase/chain length factor (KS/CLF) complexes (YsfB/C, YsfD/E, and YsfJ/K). Through in vivo gene inactivation and in vitro reconstitution, as well as an intracellular tagged carrier-protein tracking (ITCT) strategy developed in this study, we successfully elucidated the isomerase-dependent ACP-tethered polyunsaturated chain elongation process. The three KS/CLFs were revealed to modularly assemble different parts of the youssoufene skeleton, during which benzene ring closure happens right after the formation of an ACP-tethered C18 polyene. Of note, the ITCT strategy could significantly contribute to the elucidation of other carrier-protein-dependent biosynthetic machineries.
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Affiliation(s)
- Zirong Deng
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Jing Liu
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Tong Li
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Huayue Li
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Zengzhi Liu
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Yujing Dong
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Wenli Li
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
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5
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Deng Z, Liu J, Li T, Li H, Liu Z, Dong Y, Li W. An Unusual Type II Polyketide Synthase System Involved in Cinnamoyl Lipid Biosynthesis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Zirong Deng
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
| | - Jing Liu
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
| | - Tong Li
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
| | - Huayue Li
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China
| | - Zengzhi Liu
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
| | - Yujing Dong
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
| | - Wenli Li
- Key Laboratory of Marine Drugs Ministry of Education School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China
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6
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Structural basis for selectivity in a highly reducing type II polyketide synthase. Nat Chem Biol 2020; 16:776-782. [PMID: 32367018 DOI: 10.1038/s41589-020-0530-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 03/27/2020] [Indexed: 01/18/2023]
Abstract
In type II polyketide synthases (PKSs), the ketosynthase-chain length factor (KS-CLF) complex catalyzes polyketide chain elongation with the acyl carrier protein (ACP). Highly reducing type II PKSs, represented by IgaPKS, produce polyene structures instead of the well-known aromatic skeletons. Here, we report the crystal structures of the Iga11-Iga12 (KS-CLF) heterodimer and the covalently cross-linked Iga10=Iga11-Iga12 (ACP=KS-CLF) tripartite complex. The latter structure revealed the molecular basis of the interaction between Iga10 and Iga11-Iga12, which differs from that between the ACP and KS of Escherichia coli fatty acid synthase. Furthermore, the reaction pocket structure and site-directed mutagenesis revealed that the negative charge of Asp 113 of Iga11 prevents further condensation using a β-ketoacyl product as a substrate, which distinguishes IgaPKS from typical type II PKSs. This work will facilitate the future rational design of PKSs.
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7
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Kilgour SL, Kilgour DPA, Prasongpholchai P, O'Connor PB, Tosin M. A Light-Activated Acyl Carrier Protein "Trap" for Intermediate Capture in Type II Iterative Polyketide Biocatalysis. Chemistry 2019; 25:16515-16518. [PMID: 31596972 PMCID: PMC6972679 DOI: 10.1002/chem.201903662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/03/2019] [Indexed: 01/24/2023]
Abstract
A discrete acyl carrier protein (ACP) bearing a photolabile nonhydrolysable carba(dethia) malonyl pantetheine cofactor was chemoenzymatically prepared and utilised for the trapping of biosynthetic polyketide intermediates following light activation. From the in vitro assembly of the polyketides SEK4 and SEK4b, by the type II actinorhodin "minimal" polyketide synthase (PKS), a range of putative ACP-bound diketides, tetraketides, pentaketides and hexaketides were identified and characterised by FT-ICR-MS, providing direct insights on active site accessibility and substrate processing for this enzyme class.
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Affiliation(s)
| | - David P. A. Kilgour
- Department of Chemistry and ForensicsNottingham Trent UniversityNottinghamNG11 8NSUK
| | | | - Peter B. O'Connor
- Department of ChemistryUniversity of WarwickLibrary RoadCoventryCV4 7ALUK
| | - Manuela Tosin
- Department of ChemistryUniversity of WarwickLibrary RoadCoventryCV4 7ALUK
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8
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Abstract
This review highlights the protein–protein interactions between type II post-PKS tailoring enzymes with an emphasis on gilvocarcin and mithramycin.
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Affiliation(s)
- Redding Gober
- Department of Pharmaceutical Sciences
- College of Pharmacy
- University of Kentucky
- Lexington
- USA
| | - Ryan Wheeler
- Department of Pharmaceutical Sciences
- College of Pharmacy
- University of Kentucky
- Lexington
- USA
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences
- College of Pharmacy
- University of Kentucky
- Lexington
- USA
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9
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Du D, Katsuyama Y, Shin-ya K, Ohnishi Y. Reconstitution of a Type II Polyketide Synthase that Catalyzes Polyene Formation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201709636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Danyao Du
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Yohei Katsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Kazuo Shin-ya
- National Institute of Advanced Industrial Science and Technology (AIST); 2-4-7, Aomi Koto-ku Tokyo 135-0064 Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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10
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Du D, Katsuyama Y, Shin-ya K, Ohnishi Y. Reconstitution of a Type II Polyketide Synthase that Catalyzes Polyene Formation. Angew Chem Int Ed Engl 2018; 57:1954-1957. [DOI: 10.1002/anie.201709636] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/11/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Danyao Du
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Yohei Katsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Kazuo Shin-ya
- National Institute of Advanced Industrial Science and Technology (AIST); 2-4-7, Aomi Koto-ku Tokyo 135-0064 Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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11
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Davis E, Sloan T, Aurelius K, Barbour A, Bodey E, Clark B, Dennis C, Drown R, Fleming M, Humbert A, Glasgo E, Kerns T, Lingro K, McMillin M, Meyer A, Pope B, Stalevicz A, Steffen B, Steindl A, Williams C, Wimberley C, Zenas R, Butela K, Wildschutte H. Antibiotic discovery throughout the Small World Initiative: A molecular strategy to identify biosynthetic gene clusters involved in antagonistic activity. Microbiologyopen 2017; 6. [PMID: 28110506 PMCID: PMC5458470 DOI: 10.1002/mbo3.435] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 12/25/2022] Open
Abstract
The emergence of bacterial pathogens resistant to all known antibiotics is a global health crisis. Adding to this problem is that major pharmaceutical companies have shifted away from antibiotic discovery due to low profitability. As a result, the pipeline of new antibiotics is essentially dry and many bacteria now resist the effects of most commonly used drugs. To address this global health concern, citizen science through the Small World Initiative (SWI) was formed in 2012. As part of SWI, students isolate bacteria from their local environments, characterize the strains, and assay for antibiotic production. During the 2015 fall semester at Bowling Green State University, students isolated 77 soil‐derived bacteria and genetically characterized strains using the 16S rRNA gene, identified strains exhibiting antagonistic activity, and performed an expanded SWI workflow using transposon mutagenesis to identify a biosynthetic gene cluster involved in toxigenic compound production. We identified one mutant with loss of antagonistic activity and through subsequent whole‐genome sequencing and linker‐mediated PCR identified a 24.9 kb biosynthetic gene locus likely involved in inhibitory activity in that mutant. Further assessment against human pathogens demonstrated the inhibition of Bacillus cereus, Listeria monocytogenes, and methicillin‐resistant Staphylococcus aureus in the presence of this compound, thus supporting our molecular strategy as an effective research pipeline for SWI antibiotic discovery and genetic characterization.
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Affiliation(s)
- Elizabeth Davis
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Tyler Sloan
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Krista Aurelius
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Angela Barbour
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Elijah Bodey
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Brigette Clark
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Celeste Dennis
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Rachel Drown
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Megan Fleming
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Allison Humbert
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Elizabeth Glasgo
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Trent Kerns
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Kelly Lingro
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - MacKenzie McMillin
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Aaron Meyer
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Breanna Pope
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - April Stalevicz
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Brittney Steffen
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Austin Steindl
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Carolyn Williams
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Carmen Wimberley
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Robert Zenas
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
| | - Kristen Butela
- Department of BiologySeton Hill UniversityGreensburgPAUSA
| | - Hans Wildschutte
- Department of Biological SciencesBowling Green State UniversityBowling GreenOHUSA
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12
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Du D, Katsuyama Y, Onaka H, Fujie M, Satoh N, Shin-ya K, Ohnishi Y. Production of a Novel Amide-Containing Polyene by Activating a Cryptic Biosynthetic Gene Cluster inStreptomycessp. MSC090213JE08. Chembiochem 2016; 17:1464-71. [DOI: 10.1002/cbic.201600167] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Danyao Du
- Department of Biotechnology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Yohei Katsuyama
- Department of Biotechnology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Hiroyasu Onaka
- Department of Biotechnology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Manabu Fujie
- Okinawa Institute of Science and Technology Graduate University; 1919-1 Tancha, Onna-son Kunigami-gun Okinawa 904-0495 Japan
| | - Noriyuki Satoh
- Okinawa Institute of Science and Technology Graduate University; 1919-1 Tancha, Onna-son Kunigami-gun Okinawa 904-0495 Japan
| | - Kazuo Shin-ya
- National Institute of Advanced Industrial Science and Technology (AIST); 2-4-7 Aomi Koto-ku Tokyo 135-0064 Japan
| | - Yasuo Ohnishi
- Department of Biotechnology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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13
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Evolution of chemical diversity by coordinated gene swaps in type II polyketide gene clusters. Proc Natl Acad Sci U S A 2015; 112:13952-7. [PMID: 26499248 DOI: 10.1073/pnas.1511688112] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Natural product biosynthetic pathways generate molecules of enormous structural complexity and exquisitely tuned biological activities. Studies of natural products have led to the discovery of many pharmaceutical agents, particularly antibiotics. Attempts to harness the catalytic prowess of biosynthetic enzyme systems, for both compound discovery and engineering, have been limited by a poor understanding of the evolution of the underlying gene clusters. We developed an approach to study the evolution of biosynthetic genes on a cluster-wide scale, integrating pairwise gene coevolution information with large-scale phylogenetic analysis. We used this method to infer the evolution of type II polyketide gene clusters, tracing the path of evolution from the single ancestor to those gene clusters surviving today. We identified 10 key gene types in these clusters, most of which were swapped in from existing cellular processes and subsequently specialized. The ancestral type II polyketide gene cluster likely comprised a core set of five genes, a roster that expanded and contracted throughout evolution. A key C24 ancestor diversified into major classes of longer and shorter chain length systems, from which a C20 ancestor gave rise to the majority of characterized type II polyketide antibiotics. Our findings reveal that (i) type II polyketide structure is predictable from its gene roster, (ii) only certain gene combinations are compatible, and (iii) gene swaps were likely a key to evolution of chemical diversity. The lessons learned about how natural selection drives polyketide chemical innovation can be applied to the rational design and guided discovery of chemicals with desired structures and properties.
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14
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Khosla C, Herschlag D, Cane DE, Walsh CT. Assembly line polyketide synthases: mechanistic insights and unsolved problems. Biochemistry 2014; 53:2875-83. [PMID: 24779441 PMCID: PMC4020578 DOI: 10.1021/bi500290t] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Two hallmarks of assembly line polyketide synthases have motivated an interest in these unusual multienzyme systems, their stereospecificity and their capacity for directional biosynthesis. In this review, we summarize the state of knowledge regarding the mechanistic origins of these two remarkable features, using the 6-deoxyerythronolide B synthase as a prototype. Of the 10 stereocenters in 6-deoxyerythronolide B, the stereochemistry of nine carbon atoms is directly set by ketoreductase domains, which catalyze epimerization and/or diastereospecific reduction reactions. The 10th stereocenter is established by the sequential action of three enzymatic domains. Thus, the problem has been reduced to a challenge in mainstream enzymology, where fundamental gaps remain in our understanding of the structural basis for this exquisite stereochemical control by relatively well-defined active sites. In contrast, testable mechanistic hypotheses for the phenomenon of vectorial biosynthesis are only just beginning to emerge. Starting from an elegant theoretical framework for understanding coupled vectorial processes in biology [Jencks, W. P. (1980) Adv. Enzymol. Relat. Areas Mol. Biol. 51, 75-106], we present a simple model that can explain assembly line polyketide biosynthesis as a coupled vectorial process. Our model, which highlights the important role of domain-domain interactions, not only is consistent with recent observations but also is amenable to further experimental verification and refinement. Ultimately, a definitive view of the coordinated motions within and between polyketide synthase modules will require a combination of structural, kinetic, spectroscopic, and computational tools and could be one of the most exciting frontiers in 21st Century enzymology.
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Affiliation(s)
- Chaitan Khosla
- Departments of Chemical Engineering, Chemistry, and Biochemistry, Stanford University , Stanford, California 94305, United States
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Waldman AJ, Balskus EP. Lomaiviticin biosynthesis employs a new strategy for starter unit generation. Org Lett 2014; 16:640-3. [PMID: 24383813 PMCID: PMC3965344 DOI: 10.1021/ol403714g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lomaiviticin biosynthesis is thought to utilize a propionyl starter unit for a type II polyketide synthase (PKS). Discovery of the lomaiviticin (lom) biosynthetic gene cluster suggested an unusual method for starter unit generation involving a bifunctional acyltransferase/decarboxylase (AT/DC) thus far observed only in type I PKS pathways. In vitro biochemical characterization of AT/DC Lom62 confirmed its ability to generate a propionyl-acyl carrier protein (ACP), revealing a new role for this enzymatic activity within natural product biosynthesis.
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Affiliation(s)
- Abraham J Waldman
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
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16
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Metsä-Ketelä M, Oja T, Taguchi T, Okamoto S, Ichinose K. Biosynthesis of pyranonaphthoquinone polyketides reveals diverse strategies for enzymatic carbon–carbon bond formation. Curr Opin Chem Biol 2013; 17:562-70. [DOI: 10.1016/j.cbpa.2013.06.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/30/2013] [Accepted: 06/25/2013] [Indexed: 11/26/2022]
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Lohman JR, Bingman CA, Phillips GN, Shen B. Structure of the bifunctional acyltransferase/decarboxylase LnmK from the leinamycin biosynthetic pathway revealing novel activity for a double-hot-dog fold. Biochemistry 2013; 52:902-11. [PMID: 23320975 PMCID: PMC3567400 DOI: 10.1021/bi301652y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The β-branched C3 unit in leinamycin biosynthesis is installed by a set of four proteins, LnmFKLM. In vitro biochemical investigation confirmed that LnmK is a bifunctional acyltransferase/decarboxylase (AT/DC) that catalyzes first self-acylation using methylmalonyl-CoA as a substrate and subsequently transacylation of the methylmalonyl group to the phosphopantetheinyl group of the LnmL acyl carrier protein [Liu, T., Huang, Y., and Shen, B. (2009) J. Am. Chem. Soc. 131, 6900-6901]. LnmK shows no sequence homology to proteins of known function, representing a new family of AT/DC enzymes. Here we report the X-ray structure of LnmK. LnmK is homodimer with each of the monomers adopting a double-hot-dog fold. Cocrystallization of LnmK with methylmalonyl-CoA revealed an active site tunnel terminated by residues from the dimer interface. In contrast to canonical AT and ketosynthase enzymes that employ Ser or Cys as an active site residue, none of these residues are found in the vicinity of the LnmK active site. Instead, three tyrosines were identified, one of which, Tyr62, was established, by site-directed mutagenesis, to be the most likely active site residue for the AT activity of LnmK. LnmK represents the first AT enzyme that employs a Tyr as an active site residue and the first member of the family of double-hot-dog fold enzymes that displays an AT activity known to date. The LnmK structure sets the stage for probing of the DC activity of LnmK through site-directed mutagenesis. These findings highlight natural product biosynthetic machinery as a rich source of novel enzyme activities, mechanisms, and structures.
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Affiliation(s)
- Jeremy R. Lohman
- Department of Chemistry The Scripps Research institute, Jupiter, Florida 33485
| | - Craig A. Bingman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - George N. Phillips
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
,Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251
| | - Ben Shen
- Department of Chemistry The Scripps Research institute, Jupiter, Florida 33485
,Department of Molecular Therapeutics The Scripps Research institute, Jupiter, Florida 33485
,Department of Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research institute, Jupiter, Florida 33485
,To whom correspondence should be addressed: The Scripps Research Institute, 130 Scripps Way, #3A1, Jupiter, FL 33458; Tel: (561) 228-2456; Fax: (561) 228-2472;
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Schwientek P, Szczepanowski R, Rückert C, Kalinowski J, Klein A, Selber K, Wehmeier UF, Stoye J, Pühler A. The complete genome sequence of the acarbose producer Actinoplanes sp. SE50/110. BMC Genomics 2012; 13:112. [PMID: 22443545 PMCID: PMC3364876 DOI: 10.1186/1471-2164-13-112] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/23/2012] [Indexed: 11/16/2022] Open
Abstract
Background Actinoplanes sp. SE50/110 is known as the wild type producer of the alpha-glucosidase inhibitor acarbose, a potent drug used worldwide in the treatment of type-2 diabetes mellitus. As the incidence of diabetes is rapidly rising worldwide, an ever increasing demand for diabetes drugs, such as acarbose, needs to be anticipated. Consequently, derived Actinoplanes strains with increased acarbose yields are being used in large scale industrial batch fermentation since 1990 and were continuously optimized by conventional mutagenesis and screening experiments. This strategy reached its limits and is generally superseded by modern genetic engineering approaches. As a prerequisite for targeted genetic modifications, the complete genome sequence of the organism has to be known. Results Here, we present the complete genome sequence of Actinoplanes sp. SE50/110 [GenBank:CP003170], the first publicly available genome of the genus Actinoplanes, comprising various producers of pharmaceutically and economically important secondary metabolites. The genome features a high mean G + C content of 71.32% and consists of one circular chromosome with a size of 9,239,851 bp hosting 8,270 predicted protein coding sequences. Phylogenetic analysis of the core genome revealed a rather distant relation to other sequenced species of the family Micromonosporaceae whereas Actinoplanes utahensis was found to be the closest species based on 16S rRNA gene sequence comparison. Besides the already published acarbose biosynthetic gene cluster sequence, several new non-ribosomal peptide synthetase-, polyketide synthase- and hybrid-clusters were identified on the Actinoplanes genome. Another key feature of the genome represents the discovery of a functional actinomycete integrative and conjugative element. Conclusions The complete genome sequence of Actinoplanes sp. SE50/110 marks an important step towards the rational genetic optimization of the acarbose production. In this regard, the identified actinomycete integrative and conjugative element could play a central role by providing the basis for the development of a genetic transformation system for Actinoplanes sp. SE50/110 and other Actinoplanes spp. Furthermore, the identified non-ribosomal peptide synthetase- and polyketide synthase-clusters potentially encode new antibiotics and/or other bioactive compounds, which might be of pharmacologic interest.
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Affiliation(s)
- Patrick Schwientek
- Senior research group in Genome Research of Industrial Microorganisms, Center for Biotechnology, Bielefeld University, Germany
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Analysis of the ketosynthase-chain length factor heterodimer from the fredericamycin polyketide synthase. ACTA ACUST UNITED AC 2011; 18:1021-31. [PMID: 21867917 DOI: 10.1016/j.chembiol.2011.07.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/01/2011] [Accepted: 05/03/2011] [Indexed: 11/24/2022]
Abstract
The pentadecaketide fredericamycin has the longest carbon chain backbone among polycyclic aromatic polyketide antibiotics whose biosynthetic genes have been sequenced. This backbone is synthesized by the bimodular fdm polyketide synthase (PKS). Here, we demonstrate that the bimodular fdm PKS as well as its elongation module alone synthesize undecaketides and dodecaketides. Thus, unlike other homologs, the fdm ketosynthase-chain length factor (KS-CLF) heterodimer does not exclusively control the backbone length of its natural product. Using sequence- and structure-based approaches, 48 CLF multiple mutants were engineered and analyzed. Unexpectedly, the I134F mutant was unable to turn over but could initiate and partially elongate the polyketide chain. This unprecedented mutant suggests that the KS-CLF heterodimer harbors an as yet uncharacterized chain termination mechanism. Together, our findings reveal fundamental mechanistic differences between the fdm PKS and its well-studied homologs.
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Koskela S, Söderholm PP, Ainasoja M, Wennberg T, Klika KD, Ovcharenko VV, Kylänlahti I, Auerma T, Yli-Kauhaluoma J, Pihlaja K, Vuorela PM, Teeri TH. Polyketide derivatives active against Botrytis cinerea in Gerbera hybrida. PLANTA 2011; 233:37-48. [PMID: 20878179 DOI: 10.1007/s00425-010-1277-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 09/07/2010] [Indexed: 05/22/2023]
Abstract
A previously isolated cDNA molecule from Gerbera hybrida (Asteraceae) codes for a new chalcone synthase-like polyketide synthase, 2-pyrone synthase (2PS). 2PS is able to synthesise 4-hydroxy-6-methyl-2-pyrone (triacetolactone), a putative precursor for gerberin and parasorboside, two abundant glucosides in gerbera. In this study, we show that gerbera plants transformed with the gene for 2PS in an antisense orientation and unable to synthesise gerberin and parasorboside are susceptible to Botrytis cinerea infection. In addition to the preformed glucosides, the transgenic plants also lack several compounds that are induced in control plants when infected with the mould. Some of these induced substances are effective in inhibiting fungal growth both in vitro and in vivo. Two of the phytoalexins were identified as the aglycones of gerberin and trans-parasorboside. The third phytoalexin is a rare coumarin, 4-hydroxy-5-methylcoumarin; however, it is typical of many plants of the sunflower family Asteraceae. The coumarin cannot be structurally derived from either gerberin or parasorboside, but may be derived from a related polyketide intermediate.
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Affiliation(s)
- Satu Koskela
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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21
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Lopez P, Hornung A, Welzel K, Unsin C, Wohlleben W, Weber T, Pelzer S. Isolation of the lysolipin gene cluster of Streptomyces tendae Tü 4042. Gene 2010; 461:5-14. [PMID: 20399259 DOI: 10.1016/j.gene.2010.03.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 03/31/2010] [Accepted: 03/31/2010] [Indexed: 11/24/2022]
Abstract
Streptomyces tendae Tü 4042 produces the aromatic polyketide antibiotic lysolipin. Lysolipin has strong antibacterial activity against a variety of multidrug-resistant pathogens. The complete lysolipin biosynthetic gene cluster was isolated and fully sequenced. Within a 42-kb genomic region, 42 genes were identified that code for a type II polyketide synthase (llpF, E, and D), cyclases (llpCI-CIII), methyltransferases (llpMI-MVI), a halogenase (llpH), an amidotransferase (llpA), a ferredoxin (llpK), a transporter (llpN) and regulatory proteins (llpRI-RV). In addition, 15 genes encoding enzymes involved in redox modifications of the polyketide precursor molecule (llpOI-OVIII, ZI-ZIV, U, L, and S) were present in the lysolipin biosynthetic gene cluster. With this high number of oxidoreductases, lysolipin is among the most highly modified aromatic polyketides known to date. The heterologous expression of the cluster in Streptomyces albus led to lysolipin production with a yield comparable to that of wild-type, indicating that all biosynthetic genes were successfully cloned.
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Affiliation(s)
- Patricio Lopez
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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22
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Das A, Khosla C. In vivo and in vitro analysis of the hedamycin polyketide synthase. ACTA ACUST UNITED AC 2010; 16:1197-207. [PMID: 19942143 DOI: 10.1016/j.chembiol.2009.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/19/2009] [Accepted: 11/02/2009] [Indexed: 11/25/2022]
Abstract
Hedamycin is an antitumor polyketide antibiotic with unusual biosynthetic features. Earlier sequence analysis of the hedamycin biosynthetic gene cluster implied a role for type I and type II polyketide synthases (PKSs). We demonstrate that the hedamycin minimal PKS can synthesize a dodecaketide backbone. The ketosynthase (KS) subunit of this PKS has specificity for both type I and type II acyl carrier proteins (ACPs) with which it collaborates during chain initiation and chain elongation, respectively. The KS receives a C(6) primer unit from the terminal ACP domain of HedU (a type I PKS protein) directly and subsequently interacts with the ACP domain of HedE (a type II PKS protein) during the process of chain elongation. HedE is a bifunctional protein with both ACP and aromatase activity. Its aromatase domain can modulate the chain length specificity of the minimal PKS. Chain length can also be influenced by HedA, the C-9 ketoreductase. While co-expression of the hedamycin minimal PKS and a chain-initiation module from the R1128 PKS yields an isobutyryl-primed decaketide, the orthologous PKS subunits from the hedamycin gene cluster itself are unable to prime the minimal PKS with a nonacetyl starter unit. Our findings provide new insights into the mechanism of chain initiation and elongation by type II PKSs.
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Affiliation(s)
- Abhirup Das
- Department of Chemistry, Stanford University, CA 94305-5025, USA
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23
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Abstract
Nearly a quarter-century ago, the advent of molecular genetic tools in the field of natural product biosynthesis led to the remarkable revelation that the genes responsible for the biosynthesis, regulation, and self-resistance of complex polyketide antibiotics were clustered in the genomes of the bacteria that produced these compounds. This in turn facilitated rapid cloning and sequencing of genes encoding a number of polyketide synthases (PKSs). By now, it is abundantly clear that, notwithstanding extraordinary architectural and biocatalytic diversity, all PKSs are evolutionarily related enzyme assemblies. As such, understanding the molecular logic for the biosynthesis of literally thousands of amazing polyketide natural products made by nature can benefit enormously from detailed investigations into a few "model systems". For nearly the past two decades, our laboratory has focused its efforts on two such PKSs. One of them synthesizes two polyketides in approximately equal ratios, SEK4 and SEK4b, and both shunt products from the pathway that leads to the biosynthesis of the pigmented antibiotic actinorhodin. The other synthesizes 6-deoxyerythronolide B, the first isolable intermediate in the biosynthetic pathway for the widely used antibacterial agent erythromycin. Our present-day knowledge of the structures and mechanisms of these two PKSs is summarized here.
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Affiliation(s)
- Chaitan Khosla
- Stanford University, Stanford, California 94305-5080, USA.
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25
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26
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Abstract
Natural products, produced chiefly by microorganisms and plants, can be large and structurally complex molecules. These molecules are manufactured by cellular assembly lines, in which enzymes construct the molecules in a stepwise fashion. The means by which enzymes interact and work together in a modular fashion to create diverse structural features has been an active area of research; the work has provided insight into the fine details of biosynthesis. A number of polycyclic aromatic natural products--including several noteworthy anticancer, antibacterial, antifungal, antiviral, antiparasitic, and other medicinally significant substances--are synthesized by polyketide synthases (PKSs) in soil-borne bacteria called actinomycetes. Concerted biosynthetic, enzymological, and structural biological investigations into these modular enzyme systems have yielded interesting mechanistic insights. A core module called the minimal PKS is responsible for synthesizing a highly reactive, protein-bound poly-beta-ketothioester chain. In the absence of other enzymes, the minimal PKS also catalyzes chain initiation and release, yielding an assortment of polycyclic aromatic compounds. In the presence of an initiation PKS module, polyketide backbones bearing additional alkyl, alkenyl, or aryl primer units are synthesized, whereas a range of auxiliary PKS enzymes and tailoring enzymes convert the product of the minimal PKS into the final natural product. In this Account, we summarize the knowledge that has been gained regarding this family of PKSs through recent investigations into the biosynthetic pathways of two natural products, actinorhodin and R1128 (A-D). We also discuss the practical relevance of these fundamental insights for the engineered biosynthesis of new polycyclic aromatic compounds. With a deeper understanding of the biosynthetic process in hand, we can assert control at various stages of molecular construction and thus introduce unnatural functional groups in the process. The metabolic engineer affords a number of new avenues for creating novel molecular structures that will likely have properties akin to their fully natural cousins.
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Affiliation(s)
| | - Chaitan Khosla
- Department of Chemistry
- Department of Chemical Engineering
- Department of Biochemistry, Stanford University, Stanford, California 94305-5025
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27
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Worthington AS, Hur GH, Meier JL, Cheng Q, Moore BS, Burkart MD. Probing the compatibility of type II ketosynthase-carrier protein partners. Chembiochem 2009; 9:2096-103. [PMID: 18666307 DOI: 10.1002/cbic.200800198] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Drug discovery often begins with the screening of large compound libraries to identify lead compounds. Recently, the enzymes that are involved in the biosynthesis of natural products have been investigated for their potential to generate new, diverse compound libraries. There have been several approaches toward this end, including altering the substrate specificities of the enzymes involved in natural product biosynthesis and engineering functional communication between enzymes from different biosynthetic pathways. While there exist assays to assess the substrate specificity of enzymes involved in these pathways, there is no simple method for determining whether enzymes from different synthases will function cooperatively to generate the desired product(s). Herein we report a method that provides insight into both substrate specificity and compatibility of protein-protein interactions between the acyl carrier protein (ACP) and ketosynthase (KS) domains involved in fatty acid and polyketide biosynthesis. Our technique uses a one-pot chemoenzymatic method to generate post-translationally modified ACPs that are capable of covalently interacting with KS domains from different biosynthetic systems. The extent of interaction between ACPs and KSs from different systems is easily detected and quantified by a gel-based method. Our results are consistent with previous studies of substrate specificity and ACP-KS binding interactions and provide new insight into unnatural substrate and protein interactions.
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Affiliation(s)
- Andrew S Worthington
- Department of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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28
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Castaldo G, Zucko J, Heidelberger S, Vujaklija D, Hranueli D, Cullum J, Wattana-Amorn P, Crump MP, Crosby J, Long PF. Proposed Arrangement of Proteins Forming a Bacterial Type II Polyketide Synthase. ACTA ACUST UNITED AC 2008; 15:1156-65. [DOI: 10.1016/j.chembiol.2008.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 08/09/2008] [Accepted: 09/04/2008] [Indexed: 11/16/2022]
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Brachmann AO, Joyce SA, Jenke-Kodama H, Schwär G, Clarke DJ, Bode HB. A Type II Polyketide Synthase is Responsible for Anthraquinone Biosynthesis inPhotorhabdus luminescens. Chembiochem 2007; 8:1721-8. [PMID: 17722122 DOI: 10.1002/cbic.200700300] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Type II polyketide synthases are involved in the biosynthesis of numerous clinically relevant secondary metabolites with potent antibiotic or anticancer activity. Until recently the only known producers of type II PKSs were members of the Gram-positive actimomycetes, well-known producers of secondary metabolites in general. Here we present the second example of a type II PKS from Gram-negative bacteria. We have identified the biosynthesis gene cluster responsible for the production of anthraquinones (AQs) from the entomopathogenic bacterium Photorhabdus luminescens. This is the first example of AQ production in Gram-negative bacteria, and their heptaketide origin was confirmed by feeding experiments. Deletion of a cyclase/aromatase involved in AQ biosynthesis resulted in accumulation of mutactin and dehydromutactin, which have been described as shunt products of typical octaketide compounds from streptomycetes, and a pathway for AQ formation from octaketide intermediates is discussed.
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Affiliation(s)
- Alexander O Brachmann
- Pharmazeutische Biotechnologie, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany
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Abstract
6-Deoxyerythronolide B, the macrocyclic aglycone of the antibiotic erythromycin, is synthesized by a polyketide synthase (PKS) that has emerged as the prototypical modular megasynthase. A variety of molecular biological, protein chemical, and biosynthetic experiments over the past two decades have yielded insights into its mechanistic features. More recently, high-resolution structural images of portions of the 6-deoxyerythronolide B synthase have provided a platform for interpreting this wealth of biochemical data, while at the same time presenting a fundamentally new basis for the design of more detailed investigations into this remarkable enzyme. For example, the critical roles of domain-domain interactions and nonconserved linkers, as well as large interdomain movements in the structure and function of modular PKSs, have been highlighted. In turn, these insights point the way forward for more sophisticated and efficient biosynthetic engineering of complex polyketide natural products.
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Affiliation(s)
- Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA.
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31
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Mercer AC, Burkart MD. The ubiquitous carrier protein--a window to metabolite biosynthesis. Nat Prod Rep 2007; 24:750-73. [PMID: 17653358 DOI: 10.1039/b603921a] [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] [Indexed: 11/21/2022]
Abstract
Nature has developed a remarkable strategy to isolate metabolites from the milieu of the cell for chemical modification through the use of carrier proteins. Common to both primary and secondary metabolic pathways, acyl-carrier proteins constitute a conserved protein architecture which mediate the biosynthesis of a variety of metabolic products. Analogies have been made between the carrier protein and solid phase resin for chemical synthesis, as both entities provide a mechanism to separate compounds of interest from complex mixtures for selective chemical modification. However, there is significantly more to the carrier protein than an attachment point. In this review, we aim to systematically characterize the role of carrier proteins in various metabolic pathways and outline their utility in biosynthesis and biotechnology; 185 references are cited.
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Affiliation(s)
- Andrew C Mercer
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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32
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Sandmann A, Dickschat J, Jenke-Kodama H, Kunze B, Dittmann E, Müller R. A Type II Polyketide Synthase from the Gram-Negative BacteriumStigmatella aurantiaca Is Involved in Aurachin Alkaloid Biosynthesis. Angew Chem Int Ed Engl 2007; 46:2712-6. [PMID: 17335090 DOI: 10.1002/anie.200603513] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Axel Sandmann
- Pharmaceutical Biotechnology, Saarland University, P.O. Box 151150, 66041 Saarbrücken, Germany
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33
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Sandmann A, Dickschat J, Jenke-Kodama H, Kunze B, Dittmann E, Müller R. Aurachin-Biosynthese im Gram-negativen Bakterium Stigmatella aurantiaca: Beteiligung einer Typ-II-Polyketidsynthase. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200603513] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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34
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Anthracycline Biosynthesis: Genes, Enzymes and Mechanisms. ANTHRACYCLINE CHEMISTRY AND BIOLOGY I 2007. [DOI: 10.1007/128_2007_14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Fischbach MA, Walsh CT. Assembly-Line Enzymology for Polyketide and Nonribosomal Peptide Antibiotics: Logic, Machinery, and Mechanisms. Chem Rev 2006; 106:3468-96. [PMID: 16895337 DOI: 10.1021/cr0503097] [Citation(s) in RCA: 1039] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael A Fischbach
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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36
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Peric-Concha N, Borovicka B, Long PF, Hranueli D, Waterman PG, Hunter IS. Ablation of the otcC Gene Encoding a Post-polyketide Hydroxylase from the Oxytetracyline Biosynthetic Pathway in Streptomyces rimosus Results in Novel Polyketides with Altered Chain Length. J Biol Chem 2005; 280:37455-60. [PMID: 16148009 DOI: 10.1074/jbc.m503191200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxytetracycline (OTC) is a 19-carbon polyketide antibiotic made by Streptomyces rimosus. The otcC gene encodes an anhydrotetracycline oxygenase that catalyzes a hydroxylation of the anthracycline structure at position C-6 after biosynthesis of the polyketide backbone is completed. A recombinant strain of S. rimosus that was disrupted in the genomic copy of otcC synthesized a novel C-17 polyketide. This result indicates that the absence of the otcC gene product significantly influences the ability of the OTC "minimal" polyketide synthase to make a polyketide product of the correct chain length. A mutant copy of otcC was made by site-directed mutagenesis of three essential glycine codons located within the putative NADPH-binding domain. The mutant gene was expressed in Escherichia coli, and biochemical analysis confirmed that the gene product was catalytically inactive. When the mutant gene replaced the ablated gene in the chromosome of S. rimosus, the ability to make a 19-carbon backbone was restored, indicating that OtcC is an essential partner in the quaternary structure of the synthase complex.
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Anderson I, Sorokin A, Kapatral V, Reznik G, Bhattacharya A, Mikhailova N, Burd H, Joukov V, Kaznadzey D, Walunas T, Larsen N, Pusch G, Liolios K, Grechkin Y, Lapidus A, Goltsman E, Chu L, Fonstein M, Ehrlich SD, Overbeek R, Kyrpides N, Ivanova N. Comparative genome analysis ofBacillus cereusgroup genomes withBacillus subtilis. FEMS Microbiol Lett 2005; 250:175-84. [PMID: 16099605 DOI: 10.1016/j.femsle.2005.07.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 06/22/2005] [Accepted: 07/01/2005] [Indexed: 11/24/2022] Open
Abstract
Genome features of the Bacillus cereus group genomes (representative strains of Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis sub spp. israelensis) were analyzed and compared with the Bacillus subtilis genome. A core set of 1381 protein families among the four Bacillus genomes, with an additional set of 933 families common to the B. cereus group, was identified. Differences in signal transduction pathways, membrane transporters, cell surface structures, cell wall, and S-layer proteins suggesting differences in their phenotype were identified. The B. cereus group has signal transduction systems including a tyrosine kinase related to two-component system histidine kinases from B. subtilis. A model for regulation of the stress responsive sigma factor sigmaB in the B. cereus group different from the well studied regulation in B. subtilis has been proposed. Despite a high degree of chromosomal synteny among these genomes, significant differences in cell wall and spore coat proteins that contribute to the survival and adaptation in specific hosts has been identified.
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Affiliation(s)
- Iain Anderson
- Integrated Genomics, 2201 W. Campbell Park Dr., Chicago, IL 60612, USA
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38
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González-Lergier J, Broadbelt LJ, Hatzimanikatis V. Theoretical Considerations and Computational Analysis of the Complexity in Polyketide Synthesis Pathways. J Am Chem Soc 2005; 127:9930-8. [PMID: 15998100 DOI: 10.1021/ja051586y] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emergence of antimicrobial resistance has led to an increase in research directed toward the engineering of novel polyketides. To date, less than 10 000 polyketide structures have been discovered experimentally; however, the theoretical analysis of polyketide biosynthesis performed suggests that over a billion possible structures can be synthesized. Polyketide synthesis, which involves the formation of a linear chain and its subsequent cyclization, is catalyzed by an enzyme complex called polyketide synthase (PKS). There are a number of variables in the linear chain synthesis controlled by the PKS: the number, identity, stereochemistry and sequence of the monomer units used in the elongation steps, and the degree of reduction that occurs after each of the condensation reactions. The theoretical analysis performed demonstrates that changes in these variables lead to the formation of different polyketide linear chains and, consequently, a high diversity of polyketide structures. The complexity in the number of possible structures led to the implementation of this system in BNICE, a computational framework that generates all possible biochemical pathways using a given set of enzyme reaction rules. This formulation allowed the analysis of the evolution of diversity in the synthesis mechanism and the construction of the pathway architecture of polyketide biosynthesis. It is expected that, after future implementation of the cyclization reactions, this framework can be used to identify all possible polyketides and their corresponding synthesis pathways. Consequently, this formulation would prove useful in guiding experimental approaches to engineer novel polyketides, a number of which will likely have medicinal properties.
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Affiliation(s)
- Joanna González-Lergier
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
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Rahman AS, Hothersall J, Crosby J, Simpson TJ, Thomas CM. Tandemly Duplicated Acyl Carrier Proteins, Which Increase Polyketide Antibiotic Production, Can Apparently Function Either in Parallel or in Series. J Biol Chem 2005; 280:6399-408. [PMID: 15583005 DOI: 10.1074/jbc.m409814200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyketide biosynthesis involves the addition of subunits commonly derived from malonate or methylmalonate to a starter unit such as acetate. Type I polyketide synthases are multifunctional polypeptides that contain one or more modules, each of which normally contains all the enzymatic domains for a single round of extension and modification of the polyketide backbone. Acyl carrier proteins (ACP(s)) hold the extender unit to which the starter or growing chain is added. Normally there is one ACP for each ketosynthase module. However, there are an increasing number of known examples of tandemly repeated ACP domains, whose function is as yet unknown. For the doublet and triplet ACP domains in the biosynthetic pathway for the antibiotic mupirocin from Pseudomonas fluorescens NCIMB10586 we have inactivated ACP domains by inframe deletion and amino acid substitution of the active site serine. By deletion analysis each individual ACP from a cluster can provide a basic but reduced activity for the pathway. In the doublet cluster, substitution analysis indicates that the pathway may follow two parallel routes, one via each of the ACPs, thus increasing overall pathway flow. In the triplet cluster, substitution in ACP5 blocked the pathway. Thus ACP5 appears to be arranged "in series" to ACP6 and ACP7. Thus although both the doublet and triplet clusters increase antibiotic production, the mechanisms by which they do this appear to be different and depend specifically on the biosynthetic stage involved. The function of some ACPs may be determined by their location in the protein rather than absolute enzymic activity.
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Affiliation(s)
- Ayesha S Rahman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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40
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Bililign T, Griffith BR, Thorson JS. Structure, activity, synthesis and biosynthesis of aryl-C-glycosides. Nat Prod Rep 2005; 22:742-60. [PMID: 16311633 DOI: 10.1039/b407364a] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The focus of this review is to highlight the structure, bioactivity and biosynthesis of naturally occurring aryl-C-glycosides. General synthetic methods and their relevance to proposed biochemical mechanisms for the aryl-C-glycoside bond formation are also presented.
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Affiliation(s)
- Tsion Bililign
- Chemistry Department, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
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41
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Tang Y, Lee TS, Lee HY, Khosla C. Exploring the biosynthetic potential of bimodular aromatic polyketide synthases. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.05.118] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Keatinge-Clay AT, Maltby DA, Medzihradszky KF, Khosla C, Stroud RM. An antibiotic factory caught in action. Nat Struct Mol Biol 2004; 11:888-93. [PMID: 15286722 DOI: 10.1038/nsmb808] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Accepted: 06/23/2004] [Indexed: 11/09/2022]
Abstract
The synthesis of aromatic polyketides, such as actinorhodin, tetracycline and doxorubicin, begins with the formation of a polyketide chain. In type II polyketide synthases (PKSs), chains are polymerized by the heterodimeric ketosynthase-chain length factor (KS-CLF). Here we present the 2.0-A structure of the actinorhodin KS-CLF, which shows polyketides being elongated inside an amphipathic tunnel approximately 17 A in length at the heterodimer interface. The structure resolves many of the questions about the roles of KS and CLF. Although CLF regulates chain length, it does not have an active site; KS must catalyze both chain initiation and elongation. We provide evidence that the first cyclization of the polyketide occurs within the KS-CLF tunnel. The mechanistic details of this central PKS polymerase could guide biosynthetic chemists in designing new pharmaceuticals and polymers.
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Affiliation(s)
- Adrian T Keatinge-Clay
- Graduate Group in Biophysics, University of California San Francisco, San Francisco, California 94107-2240, USA
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43
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Thompson TB, Katayama K, Watanabe K, Hutchinson CR, Rayment I. Structural and functional analysis of tetracenomycin F2 cyclase from Streptomyces glaucescens. A type II polyketide cyclase. J Biol Chem 2004; 279:37956-63. [PMID: 15231835 DOI: 10.1074/jbc.m406144200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tetracenomycin F2 cyclase (tcmI gene product), catalyzes an aromatic rearrangement in the biosynthetic pathway for tetracenomycin C in Streptomyces glaucescens. The x-ray structure of this small enzyme has been determined to 1.9-A resolution together with an analysis of site-directed mutants of potential catalytic residues. The protein exhibits a dimeric betaalphabeta ferredoxin-like fold that utilizes strand swapping between subunits in its assembly. The fold is dominated by four strands of antiparallel sheet and a layer of alpha-helices, which creates a cavity that is proposed to be the active site. This type of secondary structural arrangement has been previously observed in polyketide monooxygenases and suggests an evolutionary relationship between enzymes that catalyze adjacent steps in these biosynthetic pathways. Mutational analysis of all of the obvious catalytic bases within the active site suggests that the enzyme functions to steer the chemical outcome of the cyclization rather than providing a specific catalytic group. Together, the structure and functional analysis provide insight into the structural framework necessary to perform the complex rearrangements catalyzed by this class of polyketide cyclases.
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Affiliation(s)
- Thomas B Thompson
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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44
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Abstract
Combinatorial biosynthesis involves the genetic manipulation of natural product biosynthetic enzymes to produce potential new drug candidates that would otherwise be difficult to obtain. In either a theoretical or practical sense, the number of combinations possible from different types of natural product pathways ranges widely. Enzymes that have been the most amenable to this technology synthesize the polyketides, nonribosomal peptides, and hybrids of the two. The number of polyketide or peptide natural products theoretically possible is huge, but considerable work remains before these large numbers can be realized. Nevertheless, many analogs have been created by this technology, providing useful structure-activity relationship data and leading to a few compounds that may reach the clinic in the next few years. In this review the focus is on recent advances in our understanding of how different enzymes for natural product biosynthesis can be used successfully in this technology.
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Hertweck C, Xiang L, Kalaitzis JA, Cheng Q, Palzer M, Moore BS. Context-Dependent Behavior of the Enterocin Iterative Polyketide Synthase. ACTA ACUST UNITED AC 2004; 11:461-8. [PMID: 15123240 DOI: 10.1016/j.chembiol.2004.03.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 12/19/2003] [Accepted: 01/07/2004] [Indexed: 11/28/2022]
Abstract
Heterologous expression and mutagenesis of the enterocin type II polyketide synthase (PKS) system suggest for the first time that the association of an extended set of proteins and substrates is needed for the effective production of the enterocin-wailupemycin polyketides. In the absence of its endogenous ketoreductase (KR) EncD in either the enterocin producer "Streptomyces maritimus" or the engineered host S. lividans K4-114, the enterocin minimal PKS is unable to produce benzoate-primed polyketides, even when complemented with the homologous actinorhodin KR ActIII or with EncD active site mutants. These data suggest that the enterocin PKS requires EncD to serve a catalytic and not just a structural role in the functional PKS enzyme complex. This strongly implies that EncD reduces the polyketide chain during elongation rather than after its complete assembly, as suggested for most type II PKSs.
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Affiliation(s)
- Christian Hertweck
- Hans-Knöll-Institute for Natural Products Research, Beutenbergstrasse 11a, 07745 Jena, Germany
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46
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Tang Y, Lee TS, Khosla C. Engineered biosynthesis of regioselectively modified aromatic polyketides using bimodular polyketide synthases. PLoS Biol 2004; 2:E31. [PMID: 14966533 PMCID: PMC340942 DOI: 10.1371/journal.pbio.0020031] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 11/25/2003] [Indexed: 11/19/2022] Open
Abstract
Bacterial aromatic polyketides such as tetracycline and doxorubicin are a medicinally important class of natural products produced as secondary metabolites by actinomyces bacteria. Their backbones are derived from malonyl-CoA units by polyketide synthases (PKSs). The nascent polyketide chain is synthesized by the minimal PKS, a module consisting of four dissociated enzymes. Although the biosynthesis of most aromatic polyketide backbones is initiated through decarboxylation of a malonyl building block (which results in an acetate group), some polyketides, such as the estrogen receptor antagonist R1128, are derived from nonacetate primers. Understanding the mechanism of nonacetate priming can lead to biosynthesis of novel polyketides that have improved pharmacological properties. Recent biochemical analysis has shown that nonacetate priming is the result of stepwise activity of two dissociated PKS modules with orthogonal molecular recognition features. In these PKSs, an initiation module that synthesizes a starter unit is present in addition to the minimal PKS module. Here we describe a general method for the engineered biosynthesis of regioselectively modified aromatic polyketides. When coexpressed with the R1128 initiation module, the actinorhodin minimal PKS produced novel hexaketides with propionyl and isobutyryl primer units. Analogous octaketides could be synthesized by combining the tetracenomycin minimal PKS with the R1128 initiation module. Tailoring enzymes such as ketoreductases and cyclases were able to process the unnatural polyketides efficiently. Based upon these findings, hybrid PKSs were engineered to synthesize new anthraquinone antibiotics with predictable functional group modifications. Our results demonstrate that (i) bimodular aromatic PKSs present a general mechanism for priming aromatic polyketide backbones with nonacetate precursors; (ii) the minimal PKS controls polyketide chain length by counting the number of atoms incorporated into the backbone rather than the number of elongation cycles; and (iii) in contrast, auxiliary PKS enzymes such as ketoreductases, aromatases, and cyclases recognize specific functional groups in the backbone rather than overall chain length. Among the anthracyclines engineered in this study were compounds with (i) more superior activity than R1128 against the breast cancer cell line MCF-7 and (ii) inhibitory activity against glucose-6-phosphate translocase, an attractive target for the treatment of Type II diabetes. Analogues of microbial secondary metabolites, which include many antibiotics and antitumor drugs, can be engineered from unusual primer units of the polyketide backbone to create new medicinal compounds with promising novel pharmacological properties
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Affiliation(s)
- Yi Tang
- 1Department of Chemical Engineering, Stanford UniversityStanford, CaliforniaUnited States of America
| | - Taek Soon Lee
- 2Department of Chemistry, Stanford UniversityStanford, CaliforniaUnited States of America
| | - Chaitan Khosla
- 1Department of Chemical Engineering, Stanford UniversityStanford, CaliforniaUnited States of America
- 2Department of Chemistry, Stanford UniversityStanford, CaliforniaUnited States of America
- 3Department of Biochemistry, Stanford UniversityStanford, CaliforniaUnited States of America
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47
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Brautaset T, Borgos SEF, Sletta H, Ellingsen TE, Zotchev SB. Site-specific mutagenesis and domain substitutions in the loading module of the nystatin polyketide synthase, and their effects on nystatin biosynthesis in Streptomyces noursei. J Biol Chem 2003; 278:14913-9. [PMID: 12594224 DOI: 10.1074/jbc.m212611200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The loading module for the nystatin polyketide synthase (PKS) in Streptomyces noursei is represented by the NysA protein composed of a ketosynthase (KS(S)), acyltransferase, dehydratase, and an acyl carrier protein. The absolute requirement of this protein for initiation of nystatin biosynthesis was demonstrated by the in-frame deletion of the nysA gene in S. noursei. The role of the NysA KS(S) domain, however, remained unclear, since no data on the significance of the "active site" serine (Ser-170) residue in the loading modules of type I PKSs were available. Site-specific mutagenesis of Ser-170 both in the wild-type NysA and in the hybrid loading module containing malonyl-specific acyltransferase domain from the extender module had no effect on nystatin biosynthesis. A second mutation (S413N) of the NysA KS(S) domain was discovered that completely abolished the ability of the hybrids to restore nystatin biosynthesis, presumably by affecting the ability of the resulting proteins to catalyze the required substrate decarboxylation. In contrast, NysA and its Ser-170 mutants bearing the same S413N mutation were able to restore nystatin production to significant levels, probably by using acetyl-CoA as a starter unit. Together, these data suggest that the KS(S) domain of NysA differs from the KS(Q) domains found in the loading modules of several PKS type I systems in that the active site residue is not significant for its activity.
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Affiliation(s)
- Trygve Brautaset
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
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48
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Slayden RA, Barry CE. The role of KasA and KasB in the biosynthesis of meromycolic acids and isoniazid resistance in Mycobacterium tuberculosis. Tuberculosis (Edinb) 2003; 82:149-60. [PMID: 12464486 DOI: 10.1054/tube.2002.0333] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mycobacterium tuberculosis has two discrete beta-ketoacyl synthases encoded by kasA and kasB that are located in tandem within a five-gene operon that has been implicated in isoniazid-sensitivity and mycolic acid synthesis. We have developed an in vitro meromycolic acid synthase assay to elucidate the anabolic role of these enzymes. Overproduction of KasA and KasB individually and together in M. smegmatis enabled cell-free incorporation of [(14)C]malonyl-CoA into lipids whose chain length was dependent upon the M. tuberculosis elongating enzyme used. KasA specifically elongated palmitoyl-CoA to monounsaturated fatty acids that averaged 40 carbons in length. KasB hyperproduction in the presence of KasA produced longer chain multiunsaturated hydrocarbons averaging 54 carbons in length. These products comigrated with a synthetic standard of meromycolic acid and their production was sensitive to isoniazid, thiolactomycin, and triclosan. KasA mutations associated with isoniazid resistance produced an enzyme that had a diminished overall catalytic activity but conferred enhanced resistance to isoniazid. In vivo analysis confirmed that overexpression of each of the four mutant KasAs enhanced isoniazid resistance when compared to overexpression of wild-type KasA. These results suggest discrete anabolic roles for both KasA and KasB in mycolic acid synthesis and substantiate the involvement of KasA mutations in isoniazid resistance.
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Affiliation(s)
- R A Slayden
- Tuberculosis Research Section, Laboratory of Host Defenses, NIAID, NIH, 12441 Parklawn Dr, Rockville, MD 20852, USA
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49
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Ostash BO, Fedorenko VO. Gene engineering of novel polyketide antibiotics producers. ACTA ACUST UNITED AC 2002. [DOI: 10.7124/bc.000629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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50
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Jez JM, Noel JP. Mechanism of chalcone synthase. pKa of the catalytic cysteine and the role of the conserved histidine in a plant polyketide synthase. J Biol Chem 2000; 275:39640-6. [PMID: 11006298 DOI: 10.1074/jbc.m008569200] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyketide synthases (PKS) assemble structurally diverse natural products using a common mechanistic strategy that relies on a cysteine residue to anchor the polyketide during a series of decarboxylative condensation reactions that build the final reaction product. Crystallographic and functional studies of chalcone synthase (CHS), a plant-specific PKS, indicate that a cysteine-histidine pair (Cys(164)-His(303)) forms part of the catalytic machinery. Thiol-specific inactivation and the pH dependence of the malonyl-CoA decarboxylation reaction were used to evaluate the potential interaction between these two residues. Inactivation of CHS by iodoacetamide and iodoacetic acid targets Cys(164) in a pH-dependent manner (pK(a) = 5.50). The acidic pK(a) of Cys(164) suggests that an ionic interaction with His(303) stabilizes the thiolate anion. Consistent with this assertion, substitution of a glutamine for His(303) maintains catalytic activity but shifts the pK(a) of the thiol to 6.61. Although the H303A mutant was catalytically inactive, the pH-dependent incorporation of [(14)C]iodoacetamide into this mutant exhibits a pK(a) = 7.62. Subsequent analysis of the pH dependence of the malonyl-CoA decarboxylation reaction catalyzed by wild-type CHS and the H303Q and C164A mutants also supports the presence of an ion pair at the CHS active site. Structural and sequence conservation of a cysteine-histidine pair in the active sites of other PKS implies that a thiolate-imidazolium ion pair plays a central role in polyketide biosynthesis.
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Affiliation(s)
- J M Jez
- Structural Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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