1
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Engineering the stambomycin modular polyketide synthase yields 37-membered mini-stambomycins. Nat Commun 2022; 13:515. [PMID: 35082289 PMCID: PMC8792006 DOI: 10.1038/s41467-022-27955-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022] Open
Abstract
The modular organization of the type I polyketide synthases (PKSs) would seem propitious for rational engineering of desirable analogous. However, despite decades of efforts, such experiments remain largely inefficient. Here, we combine multiple, state-of-the-art approaches to reprogram the stambomycin PKS by deleting seven internal modules. One system produces the target 37-membered mini-stambomycin metabolites − a reduction in chain length of 14 carbons relative to the 51-membered parental compounds − but also substantial quantities of shunt metabolites. Our data also support an unprecedented off-loading mechanism of such stalled intermediates involving the C-terminal thioesterase domain of the PKS. The mini-stambomycin yields are reduced relative to wild type, likely reflecting the poor tolerance of the modules downstream of the modified interfaces to the non-native substrates. Overall, we identify factors contributing to the productivity of engineered whole assembly lines, but our findings also highlight the need for further research to increase production titers. Genetic engineering of the type I polyketide synthases (PKSs) to produce desirable analogous remains largely inefficient. Here, the authors leverage multiple approaches to delete seven internal modules from the stambomycin PKS and generate 37-membered mini-stambomycin macrolactones.
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2
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Zargar A, Valencia L, Wang J, Lal R, Chang S, Werts M, Wong AR, Hernández AC, Benites V, Baidoo EE, Katz L, Keasling JD. A bimodular PKS platform that expands the biological design space. Metab Eng 2020; 61:389-396. [DOI: 10.1016/j.ymben.2020.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 01/21/2023]
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3
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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Aaron A. Koch
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Jennifer J. Schmidt
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Andrew N. Lowell
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Current address: Department of Chemistry Virginia Tech Blacksburg VA 24061 USA
| | - Douglas A. Hansen
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Katherine M. Coburn
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Joseph A. Chemler
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - David H. Sherman
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology The University of Michigan USA
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4
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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020; 59:13575-13580. [PMID: 32357274 DOI: 10.1002/anie.202004991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Indexed: 11/09/2022]
Abstract
Engineering polyketide synthases (PKS) to produce new metabolites requires an understanding of catalytic points of failure during substrate processing. Growing evidence indicates the thioesterase (TE) domain as a significant bottleneck within engineered PKS systems. We created a series of hybrid PKS modules bearing exchanged TE domains from heterologous pathways and challenged them with both native and non-native polyketide substrates. Reactions pairing wildtype PKS modules with non-native substrates primarily resulted in poor conversions to anticipated macrolactones. Likewise, product formation with native substrates and hybrid PKS modules bearing non-cognate TE domains was severely reduced. In contrast, non-native substrates were converted by most hybrid modules containing a substrate compatible TE, directly implicating this domain as the major catalytic gatekeeper and highlighting its value as a target for protein engineering to improve analog production in PKS pathways.
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Affiliation(s)
- Aaron A Koch
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Jennifer J Schmidt
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Andrew N Lowell
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Current address: Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Douglas A Hansen
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Katherine M Coburn
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Joseph A Chemler
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - David H Sherman
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology, The University of Michigan, USA
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5
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Nivina A, Yuet KP, Hsu J, Khosla C. Evolution and Diversity of Assembly-Line Polyketide Synthases. Chem Rev 2019; 119:12524-12547. [PMID: 31838842 PMCID: PMC6935866 DOI: 10.1021/acs.chemrev.9b00525] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Indexed: 12/11/2022]
Abstract
Assembly-line polyketide synthases (PKSs) are among the most complex protein machineries known in nature, responsible for the biosynthesis of numerous compounds used in the clinic. Their present-day diversity is the result of an evolutionary path that has involved the emergence of a multimodular architecture and further diversification of assembly-line PKSs. In this review, we provide an overview of previous studies that investigated PKS evolution and propose a model that challenges the currently prevailing view that gene duplication has played a major role in the emergence of multimodularity. We also analyze the ensemble of orphan PKS clusters sequenced so far to evaluate how large the entire diversity of assembly-line PKS clusters and their chemical products could be. Finally, we examine the existing techniques to access the natural PKS diversity in natural and heterologous hosts and describe approaches to further expand this diversity through engineering.
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Affiliation(s)
- Aleksandra Nivina
- Department
of Chemistry, Stanford ChEM-H, Department of Chemical Engineering Stanford
University, Stanford, California 94305, United States
| | - Kai P. Yuet
- Department
of Chemistry, Stanford ChEM-H, Department of Chemical Engineering Stanford
University, Stanford, California 94305, United States
| | - Jake Hsu
- Department
of Chemistry, Stanford ChEM-H, Department of Chemical Engineering Stanford
University, Stanford, California 94305, United States
| | - Chaitan Khosla
- Department
of Chemistry, Stanford ChEM-H, Department of Chemical Engineering Stanford
University, Stanford, California 94305, United States
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6
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Acheampong KK, Kokona B, Braun GA, Jacobsen DR, Johnson KA, Charkoudian LK. Colorimetric Assay Reports on Acyl Carrier Protein Interactions. Sci Rep 2019; 9:15589. [PMID: 31666546 PMCID: PMC6821831 DOI: 10.1038/s41598-019-51554-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/25/2019] [Indexed: 01/15/2023] Open
Abstract
The ability to produce new molecules of potential pharmaceutical relevance via combinatorial biosynthesis hinges on improving our understanding of acyl-carrier protein (ACP)-protein interactions. However, the weak and transient nature of these interactions makes them difficult to study using traditional spectroscopic approaches. Herein we report that converting the terminal thiol of the E. coli ACP 4'-phosphopantetheine arm into a mixed disulfide with 2-nitro-5-thiobenzoate ion (TNB-) activates this site to form a selective covalent cross-link with the active site cysteine of a cognate ketoacyl synthase (KS). The concomitant release of TNB2-, which absorbs at 412 nm, provides a visual and quantitative measure of mechanistically relevant ACP-KS interactions. The colorimetric assay can propel the engineering of biosynthetic routes to novel chemical diversity by providing a high-throughput screen for functional hybrid ACP-KS partnerships as well as the discovery of novel antimicrobial agents by enabling the rapid identification of small molecule inhibitors of ACP-KS interactions.
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Affiliation(s)
- Kofi K Acheampong
- Department of Chemistry, Haverford College, Haverford, PA, 19041-1391, USA
| | - Bashkim Kokona
- Department of Chemistry, Haverford College, Haverford, PA, 19041-1391, USA
| | - Gabriel A Braun
- Department of Chemistry, Haverford College, Haverford, PA, 19041-1391, USA
| | | | - Karl A Johnson
- Department of Biology, Haverford College, Haverford, PA, 19041-1391, USA.
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7
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Gulick AM, Aldrich CC. Trapping interactions between catalytic domains and carrier proteins of modular biosynthetic enzymes with chemical probes. Nat Prod Rep 2019; 35:1156-1184. [PMID: 30046790 DOI: 10.1039/c8np00044a] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to early 2018 The Nonribosomal Peptide Synthetases (NRPSs) and Polyketide Synthases (PKSs) are families of modular enzymes that produce a tremendous diversity of natural products, with antibacterial, antifungal, immunosuppressive, and anticancer activities. Both enzymes utilize a fascinating modular architecture in which the synthetic intermediates are covalently attached to a peptidyl- or acyl-carrier protein that is delivered to catalytic domains for natural product elongation, modification, and termination. An investigation of the structural mechanism therefore requires trapping the often transient interactions between the carrier and catalytic domains. Many novel chemical probes have been produced to enable the structural and functional investigation of multidomain NRPS and PKS structures. This review will describe the design and implementation of the chemical tools that have proven to be useful in biochemical and biophysical studies of these natural product biosynthetic enzymes.
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Affiliation(s)
- Andrew M Gulick
- University at Buffalo, Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, 955 Main St, Buffalo, NY 14203, USA.
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8
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Pang B, Valencia LE, Wang J, Wan Y, Lal R, Zargar A, Keasling JD. Technical Advances to Accelerate Modular Type I Polyketide Synthase Engineering towards a Retro-biosynthetic Platform. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0083-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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9
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Abstract
Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass.
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10
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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: 92] [Impact Index Per Article: 11.5] [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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11
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Lin Z, Chen D, Liu W. Biosynthesis-based artificial evolution of microbial natural products. Sci China Chem 2016. [DOI: 10.1007/s11426-016-0062-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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12
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Klaus M, Ostrowski MP, Austerjost J, Robbins T, Lowry B, Cane DE, Khosla C. Protein-Protein Interactions, Not Substrate Recognition, Dominate the Turnover of Chimeric Assembly Line Polyketide Synthases. J Biol Chem 2016; 291:16404-15. [PMID: 27246853 DOI: 10.1074/jbc.m116.730531] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 01/08/2023] Open
Abstract
The potential for recombining intact polyketide synthase (PKS) modules has been extensively explored. Both enzyme-substrate and protein-protein interactions influence chimeric PKS activity, but their relative contributions are unclear. We now address this issue by studying a library of 11 bimodular and 8 trimodular chimeric PKSs harboring modules from the erythromycin, rifamycin, and rapamycin synthases. Although many chimeras yielded detectable products, nearly all had specific activities below 10% of the reference natural PKSs. Analysis of selected bimodular chimeras, each with the same upstream module, revealed that turnover correlated with the efficiency of intermodular chain translocation. Mutation of the acyl carrier protein (ACP) domain of the upstream module in one chimera at a residue predicted to influence ketosynthase-ACP recognition led to improved turnover. In contrast, replacement of the ketoreductase domain of the upstream module by a paralog that produced the enantiomeric ACP-bound diketide caused no changes in processing rates for each of six heterologous downstream modules compared with those of the native diketide. Taken together, these results demonstrate that protein-protein interactions play a larger role than enzyme-substrate recognition in the evolution or design of catalytically efficient chimeric PKSs.
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Affiliation(s)
- Maja Klaus
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
| | - Matthew P Ostrowski
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
| | - Jonas Austerjost
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
| | - Thomas Robbins
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
| | - Brian Lowry
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
| | - David E Cane
- the Department of Chemistry, Brown University, Providence, Rhode Island 02192-9108
| | - Chaitan Khosla
- From the Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305 and
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13
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Weissman KJ. Genetic engineering of modular PKSs: from combinatorial biosynthesis to synthetic biology. Nat Prod Rep 2016; 33:203-30. [DOI: 10.1039/c5np00109a] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This reviews covers on-going efforts at engineering the gigantic modular polyketide synthases (PKSs), highlighting both notable successes and failures.
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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
- 54505 Vandœuvre-lès-Nancy Cedex
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14
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Murphy AC, Hong H, Vance S, Broadhurst RW, Leadlay PF. Broadening substrate specificity of a chain-extending ketosynthase through a single active-site mutation. Chem Commun (Camb) 2016; 52:8373-6. [DOI: 10.1039/c6cc03501a] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An in vitro model system based on a ketosynthase domain of the erythromycin polyketide synthase was used to probe the apparent substrate tolerance of ketosynthase domains of the mycolactone polyketide synthase.
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Affiliation(s)
- Annabel C. Murphy
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
| | - Hui Hong
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
| | - Steve Vance
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
- Crescendo Biologics Ltd
| | | | - Peter F. Leadlay
- Department of Biochemistry
- University of Cambridge
- Cambridge CB2 1GA
- UK
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15
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Abstract
Polyketides are a structurally and functionally diverse family of bioactive natural products that have found widespread application as pharmaceuticals, agrochemicals, and veterinary medicines. In bacteria complex polyketides are biosynthesized by giant multifunctional megaenzymes, termed modular polyketide synthases (PKSs), which construct their products in a highly coordinated assembly line-like fashion from a pool of simple precursor substrates. Not only is the multifaceted enzymology of PKSs a fascinating target for study, but it also presents considerable opportunities for the reengineering of these systems affording access to functionally optimized unnatural natural products. Here we provide an introductory primer to modular polyketide synthase structure and function, and highlight recent advances in the characterization and exploitation of these systems.
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Affiliation(s)
- Marisa Till
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Paul R Race
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK
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16
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17
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Jenner M, Afonso JP, Bailey HR, Frank S, Kampa A, Piel J, Oldham NJ. Acyl-Chain Elongation Drives Ketosynthase Substrate Selectivity intrans-Acyltransferase Polyketide Synthases. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201410219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Jenner M, Afonso JP, Bailey HR, Frank S, Kampa A, Piel J, Oldham NJ. Acyl-chain elongation drives ketosynthase substrate selectivity in trans-acyltransferase polyketide synthases. Angew Chem Int Ed Engl 2014; 54:1817-21. [PMID: 25529827 DOI: 10.1002/anie.201410219] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 11/10/2014] [Indexed: 11/09/2022]
Abstract
Type I modular polyketide synthases (PKSs), which are responsible for the biosynthesis of many biologically active agents, possess a ketosynthase (KS) domain within each module to catalyze chain elongation. Acylation of the KS active site Cys residue is followed by transfer to malonyl-ACP to yield an extended β-ketoacyl chain (ACP = acyl carrier protein). To date, the precise contribution of KS selectivity in controlling product fidelity has been unclear. Six KS domains from trans-acyltransferase (trans-AT) PKSs were subjected to a mass spectrometry based elongation assay, and higher substrate selectivity was identified for the elongating step than in preceding acylation. A close correspondence between the observed KS selectivity and that predicted by phylogenetic analysis was seen. These findings provide insights into the mechanism of KS selectivity in this important group of PKSs, can serve as guidance for engineering, and show that targeted mutagenesis can be used to expand the repertoire of acceptable substrates.
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Affiliation(s)
- Matthew Jenner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (UK)
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19
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Koryakina I, McArthur JB, Draelos MM, Williams GJ. Promiscuity of a modular polyketide synthase towards natural and non-natural extender units. Org Biomol Chem 2014; 11:4449-58. [PMID: 23681002 DOI: 10.1039/c3ob40633d] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Combinatorial biosynthesis approaches that involve modular type I polyketide synthases (PKSs) are proven strategies for the synthesis of polyketides. In general however, such strategies are usually limited in scope and utility due to the restricted substrate specificity of polyketide biosynthetic machinery. Herein, a panel of chemo-enzymatically synthesized acyl-CoA's was used to probe the promiscuity of a polyketide synthase. Promiscuity determinants were dissected, revealing that the KS is remarkably tolerant to a diverse array of extender units, while the AT likely discriminates between extender units that are native to the producing organism. Our data provides a clear blueprint for future enzyme engineering efforts, and sets the stage for harnessing extender unit promiscuity by employing various in vivo polyketide diversification strategies.
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Affiliation(s)
- Irina Koryakina
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA
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20
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Soehano I, Yang L, Ding F, Sun H, Low ZJ, Liu X, Liang ZX. Insights into the programmed ketoreduction of partially reducing polyketide synthases: stereo- and substrate-specificity of the ketoreductase domain. Org Biomol Chem 2014; 12:8542-9. [DOI: 10.1039/c4ob01777c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Evidence are provided to support that partially reducing polyketide synthases achieve programmed ketoreduction by differential recognition of polyketide intermediates.
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Affiliation(s)
- Ishin Soehano
- School of Biological Sciences Nanyang Technological University
- , Singapore
| | - Lifeng Yang
- School of Biological Sciences Nanyang Technological University
- , Singapore
| | - Feiqing Ding
- School of Mathematics and Physics
- Nanyang Technological University
- , Singapore
| | - Huihua Sun
- School of Biological Sciences Nanyang Technological University
- , Singapore
| | - Zhen Jie Low
- School of Biological Sciences Nanyang Technological University
- , Singapore
| | - Xuewei Liu
- School of Mathematics and Physics
- Nanyang Technological University
- , Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences Nanyang Technological University
- , Singapore
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21
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Peirú S, Gramajo HC, Menzella HG. Recombinant approaches to large polyketide molecules as potential drugs. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 7:e95-e146. [PMID: 24103720 DOI: 10.1016/j.ddtec.2010.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Dunn BJ, Khosla C. Engineering the acyltransferase substrate specificity of assembly line polyketide synthases. J R Soc Interface 2013; 10:20130297. [PMID: 23720536 DOI: 10.1098/rsif.2013.0297] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Polyketide natural products act as a broad range of therapeutics, including antibiotics, immunosuppressants and anti-cancer agents. This therapeutic diversity stems from the structural diversity of these small molecules, many of which are produced in an assembly line manner by modular polyketide synthases. The acyltransferase (AT) domains of these megasynthases are responsible for selection and incorporation of simple monomeric building blocks, and are thus responsible for a large amount of the resulting polyketide structural diversity. The substrate specificity of these domains is often targeted for engineering in the generation of novel, therapeutically active natural products. This review outlines recent developments that can be used in the successful engineering of these domains, including AT sequence and structural data, mechanistic insights and the production of a diverse pool of extender units. It also provides an overview of previous AT domain engineering attempts, and concludes with proposed engineering approaches that take advantage of current knowledge. These approaches may lead to successful production of biologically active 'unnatural' natural products.
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Affiliation(s)
- Briana J Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
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23
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Xu W, Qiao K, Tang Y. Structural analysis of protein-protein interactions in type I polyketide synthases. Crit Rev Biochem Mol Biol 2012; 48:98-122. [PMID: 23249187 DOI: 10.3109/10409238.2012.745476] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Polyketide synthases (PKSs) are responsible for synthesizing a myriad of natural products with agricultural, medicinal relevance. The PKSs consist of multiple functional domains of which each can catalyze a specified chemical reaction leading to the synthesis of polyketides. Biochemical studies showed that protein-substrate and protein-protein interactions play crucial roles in these complex regio-/stereo-selective biochemical processes. Recent developments on X-ray crystallography and protein NMR techniques have allowed us to understand the biosynthetic mechanism of these enzymes from their structures. These structural studies have facilitated the elucidation of the sequence-function relationship of PKSs and will ultimately contribute to the prediction of product structure. This review will focus on the current knowledge of type I PKS structures and the protein-protein interactions in this system.
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Affiliation(s)
- Wei Xu
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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24
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Abstract
Metabolism is a highly interconnected web of chemical reactions that power life. Though the stoichiometry of metabolism is well understood, the multidimensional aspects of metabolic regulation in time and space remain difficult to define, model and engineer. Complex metabolic conversions can be performed by multiple species working cooperatively and exchanging metabolites via structured networks of organisms and resources. Within cells, metabolism is spatially regulated via sequestration in subcellular compartments and through the assembly of multienzyme complexes. Metabolic engineering and synthetic biology have had success in engineering metabolism in the first and second dimensions, designing linear metabolic pathways and channeling metabolic flux. More recently, engineering of the third dimension has improved output of engineered pathways through isolation and organization of multicell and multienzyme complexes. This review highlights natural and synthetic examples of three-dimensional metabolism both inter- and intracellularly, offering tools and perspectives for biological design.
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25
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Prasad G, Amoroso JW, Borketey LS, Schnarr NA. N-activated β-lactams as versatile reagents for acyl carrier protein labeling. Org Biomol Chem 2012; 10:1992-2002. [PMID: 22293823 DOI: 10.1039/c2ob06846j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acyl carrier proteins are critical components of fatty acid and polyketide biosynthesis. Their primary function is to shuttle intermediates between active sites via a covalently bound phosphopantetheine arm. Small molecules capable of acylating this prosthetic group will provide a simple and reversible means of introducing novel functionality onto carrier protein domains. A series of N-activated β-lactams are prepared to examine site-specific acylation of the phosphopantetheine-thiol. In general, β-lactams are found to be significantly more reactive than our previously studied β-lactones. Selectivity for the holo over apo-form of acyl carrier proteins is demonstrated indicating that only the phosphopantetheine-thiol is modified. Incorporation of an N-propargyloxycarbonyl group provides an alkyne handle for conjugation to fluorophores and affinity labels. The utility of these groups for mechanistic interrogation of a critical step in polyketide biosynthesis is examined through comparison to traditional probes. In all, we expect the probes described in this study to serve as valuable and versatile tools for mechanistic interrogation.
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Affiliation(s)
- Gitanjeli Prasad
- Department of Chemistry, University of Massachusetts, 710 N. Pleasant Street, Amherst, Massachusetts 01003, USA
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26
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27
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Murphy AC. Metabolic engineering is key to a sustainable chemical industry. Nat Prod Rep 2011; 28:1406-25. [DOI: 10.1039/c1np00029b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Neumann H, Neumann-Staubitz P. Synthetic biology approaches in drug discovery and pharmaceutical biotechnology. Appl Microbiol Biotechnol 2010; 87:75-86. [PMID: 20396881 PMCID: PMC2872025 DOI: 10.1007/s00253-010-2578-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/21/2010] [Accepted: 03/22/2010] [Indexed: 12/17/2022]
Abstract
Synthetic biology is the attempt to apply the concepts of engineering to biological systems with the aim to create organisms with new emergent properties. These organisms might have desirable novel biosynthetic capabilities, act as biosensors or help us to understand the intricacies of living systems. This approach has the potential to assist the discovery and production of pharmaceutical compounds at various stages. New sources of bioactive compounds can be created in the form of genetically encoded small molecule libraries. The recombination of individual parts has been employed to design proteins that act as biosensors, which could be used to identify and quantify molecules of interest. New biosynthetic pathways may be designed by stitching together enzymes with desired activities, and genetic code expansion can be used to introduce new functionalities into peptides and proteins to increase their chemical scope and biological stability. This review aims to give an insight into recently developed individual components and modules that might serve as parts in a synthetic biology approach to pharmaceutical biotechnology.
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Affiliation(s)
- Heinz Neumann
- Free Floater (Junior) Research Group “Applied Synthetic Biology”, Institute for Microbiology and Genetics, Georg-August University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Petra Neumann-Staubitz
- General Microbiology, Institute for Microbiology and Genetics, Georg-August University Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
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Abstract
In this chapter we describe novel methods for the design and assembly of synthetic pathways for the synthesis of polyketides and tailoring sugars. First, a generic design for type I polyketide synthase genes is presented that allows their facile assembly for the expression of chimeric enzymes in an engineered Escherichia coli host. The sequences of the synthetic genes are based on naturally occurring polyketide synthase genes but they are redesigned by custom-made software to optimize codon usage to maximize expression in E. coli and to provide a standard set of restriction sites to allow combinatorial assembly into unnatural enzymes. The methodology has been validated by building a large number of bimodular mini-PKSs that make easily assayed triketide products. Learning from the successful bimodules, a conceptual advance was made by assembling genes encoding functional trimodular enzymes, capable of making tetraketide products. Second, methods for the rapid assembly and exchange of sugar pathway genes into functional operons are described. The approach was validated by the assembly of the 15 genes for the synthesis of mycarose and desosamine in two operons, which yielded erythromycin C when coexpressed with the corresponding PKS genes. These methods are important enabling steps toward the goals of making designer drugs by polyketide synthase and sugar pathway engineering and, in the shorter term, producing by fermentation advanced intermediates for the synthesis of compounds that otherwise require large numbers of chemical steps.
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30
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Yan J, Gupta S, Sherman DH, Reynolds KA. Functional dissection of a multimodular polypeptide of the pikromycin polyketide synthase into monomodules by using a matched pair of heterologous docking domains. Chembiochem 2009; 10:1537-43. [PMID: 19437523 PMCID: PMC4652847 DOI: 10.1002/cbic.200900098] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Indexed: 11/08/2022]
Abstract
The pikromyin polyketide synthase (PKS) in Streptomyces venezulae is comprised of a loading module and six extension modules, which generate the corresponding 14-membered macrolactone product. PikAI is a multimodular component of this PKS and houses both the loading domain and the first two extension modules, joined by short intraprotein linkers. We have shown that PikAI can be separated into two proteins at either of these linkers, only when matched pairs of docking domains (DDs) from a heterologous modular phoslactomycin PKS are used in place of the intraprotein linker. In both cases the yields of pikromycin produced by the S. venezuelae mutant were 50% of that of a S. venezuelae strain expressing the native trimodular PikAI. This observation provides the first demonstration that such separations do not dramatically impact the efficiency of the entire in vivo biosynthetic process. Expression of module 2 as a monomodular protein fused to a heterologous N-terminal docking domain was also observed to give almost a tenfold improvement in the in vivo generation of pikromycin from a synthetic diketide intermediate. These results demonstrate the utility of DDs to manipulate biosynthetic processes catalyzed by modular PKSs and the quest to generate novel polyketide products.
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Affiliation(s)
- John Yan
- Department of Chemistry, Portland State University, 262 Science Building 2, 1719 SW 10th Avenue, Portland, OR 97201, FAX: 503- 725 9525
| | - Shuchi Gupta
- Department of Chemistry, Portland State University, 262 Science Building 2, 1719 SW 10th Avenue, Portland, OR 97201, FAX: 503- 725 9525
| | - David H. Sherman
- Life Sciences Institute and Department of Medicinal Chemistry, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216, Fax: 734-615-3641
| | - Kevin A. Reynolds
- Department of Chemistry, Portland State University, 262 Science Building 2, 1719 SW 10th Avenue, Portland, OR 97201, FAX: 503- 725 9525
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Khosla C, Kapur S, Cane DE. Revisiting the modularity of modular polyketide synthases. Curr Opin Chem Biol 2009; 13:135-43. [PMID: 19217343 DOI: 10.1016/j.cbpa.2008.12.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 12/25/2008] [Indexed: 11/28/2022]
Abstract
Modularity is a highly sought after feature in engineering design. A modular catalyst is a multi-component system whose parts can be predictably interchanged for functional flexibility and variety. Nearly two decades after the discovery of the first modular polyketide synthase (PKS), we critically assess PKS modularity in the face of a growing body of atomic structural and in vitro biochemical investigations. Both the architectural modularity and the functional modularity of this family of enzymatic assembly lines are reviewed, and the fundamental challenges that lie ahead for the rational exploitation of their full biosynthetic potential are discussed.
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Affiliation(s)
- Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
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32
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Li M, Chen Z, Lin X, Zhang X, Song Y, Wen Y, Li J. Engineering of avermectin biosynthetic genes to improve production of ivermectin in Streptomyces avermitilis. Bioorg Med Chem Lett 2008; 18:5359-63. [PMID: 18824353 DOI: 10.1016/j.bmcl.2008.09.061] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 09/10/2008] [Accepted: 09/16/2008] [Indexed: 11/24/2022]
Abstract
Two new recombinants of avermectin polyketide synthases were constructed by domain and module swapping in Streptomyces avermitilis 73-12. However, only the strain, S. avermitilis OI-31, formed by domain substitution could produce ivermectin. Analysis of the ivermectin synthesized gene cluster showed that decreased amount of aveC transcripts was one of the factors causing low yield of ivermectin. Overexpression of aveC could improve ivermectin yield.
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Affiliation(s)
- Meng Li
- State Key Laboratories for Agrobiotechnology and College of Biological Sciences, Beijing 100193, PR China
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33
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Magarvey NA, Fortin PD, Thomas PM, Kelleher NL, Walsh CT. Gatekeeping versus promiscuity in the early stages of the andrimid biosynthetic assembly line. ACS Chem Biol 2008; 3:542-54. [PMID: 18652473 DOI: 10.1021/cb800085g] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The antibiotic andrimid, a nanomolar inhibitor of bacterial acetyl coenzyme A carboxylase, is generated on an unusual polyketide/nonribosomal peptide enzyme assembly line in that all thiolation (T) domains/small-molecule building stations are on separate proteins. In addition, a transglutaminase homologue is used to condense andrimid building blocks together on the andrimid assembly line. The first two modules of the andrimid assembly line yields an octatrienoyl-beta-Phe-thioester tethered to the AdmI T domain, with amide bond formation carried out by a free-standing transglutaminase homologue AdmF. Analysis of the aminomutase AdmH reveals its specific conversion from l-Phe to (S)-beta-Phe, which in turn is activated by AdmJ and ATP to form (S)-beta-Phe-aminoacyl-AMP. AdmJ then transfers the (S)-beta-Phe moiety to one of the free-standing T domains, AdmI, but not AdmA, which instead gets loaded with an octatrienoyl group by other enzymes. AdmF, the amide synthase, will accept a variety of acyl groups in place of the octatrienoyl donor if presented on either AdmA or AdmI. AdmF will also use either stereoisomer of phenylalanine or beta-Phe when presented on AdmA and AdmI, but not when placed on noncognate T domains. Further, we show the polyketide synthase proteins responsible for the polyunsaturated acyl cap can be bypassed in vitro with N-acetylcysteamine as a low-molecular-weight acyl donor to AdmF and also in vivo in an Escherichia coli strain bearing the andrimid biosynthetic gene cluster with a knockout in admA.
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Affiliation(s)
- Nathan A. Magarvey
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Pascal D. Fortin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Paul M. Thomas
- Department of Chemistry, University of Illinois, Urbana−Champaign, Illinois 61801
| | - Neil L. Kelleher
- Department of Chemistry, University of Illinois, Urbana−Champaign, Illinois 61801
| | - Christopher T. Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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34
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Gupta S, Lakshmanan V, Kim BS, Fecik R, Reynolds KA. Generation of novel pikromycin antibiotic products through mutasynthesis. Chembiochem 2008; 9:1609-16. [PMID: 18512859 DOI: 10.1002/cbic.200700635] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The pikromycin polyketide synthase (PKS) of S. venezuelae, which consists of one loading module and six extension modules, is responsible for the formation of the hexaketide narbonolide, a key intermediate in the biosynthesis of the antibiotic pikromycin. S. venezuelae strains in which PikAI, which houses the loading domain and first two modules of the PKS, is either absent or catalytically inactive, produce no pikromycin product. When these strains are grown in the presence of a synthetically prepared triketide product, activated as the N-acetylcysteamine thioester, pikromycin yields are restored to as much as 11 % of that seen in the wild-type strain. Feeding analogues of the triketide intermediate provides pikromycin analogues bearing different alkyl substituents at C13 and C14. One of these analogues, Delta(15,16)-dehydropikromycin, exhibits improved antimicrobial activity relative to pikromycin.
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Affiliation(s)
- Shuchi Gupta
- Department of Chemistry, Portland State University, Portland, OR 97201, USA
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35
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Alekseyev VY, Liu CW, Cane DE, Puglisi JD, Khosla C. Solution structure and proposed domain domain recognition interface of an acyl carrier protein domain from a modular polyketide synthase. Protein Sci 2007; 16:2093-107. [PMID: 17893358 PMCID: PMC2204127 DOI: 10.1110/ps.073011407] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Polyketides are a medicinally important class of natural products. The architecture of modular polyketide synthases (PKSs), composed of multiple covalently linked domains grouped into modules, provides an attractive framework for engineering novel polyketide-producing assemblies. However, impaired domain-domain interactions can compromise the efficiency of engineered polyketide biosynthesis. To facilitate the study of these domain-domain interactions, we have used nuclear magnetic resonance (NMR) spectroscopy to determine the first solution structure of an acyl carrier protein (ACP) domain from a modular PKS, 6-deoxyerythronolide B synthase (DEBS). The tertiary fold of this 10-kD domain is a three-helical bundle; an additional short helix in the second loop also contributes to the core helical packing. Superposition of residues 14-94 of the ensemble on the mean structure yields an average atomic RMSD of 0.64 +/- 0.09 Angstrom for the backbone atoms (1.21 +/- 0.13 Angstrom for all non-hydrogen atoms). The three major helices superimpose with a backbone RMSD of 0.48 +/- 0.10 Angstrom (0.99 +/- 0.11 Angstrom for non-hydrogen atoms). Based on this solution structure, homology models were constructed for five other DEBS ACP domains. Comparison of their steric and electrostatic surfaces at the putative interaction interface (centered on helix II) suggests a model for protein-protein recognition of ACP domains, consistent with the previously observed specificity. Site-directed mutagenesis experiments indicate that two of the identified residues influence the specificity of ACP recognition.
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Affiliation(s)
- Viktor Y Alekseyev
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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36
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Thattai M, Burak Y, Shraiman BI. The origins of specificity in polyketide synthase protein interactions. PLoS Comput Biol 2007; 3:1827-35. [PMID: 17907798 PMCID: PMC1994986 DOI: 10.1371/journal.pcbi.0030186] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 08/10/2007] [Indexed: 11/18/2022] Open
Abstract
Polyketides, a diverse group of heteropolymers with antibiotic and antitumor properties, are assembled in bacteria by multiprotein chains of modular polyketide synthase (PKS) proteins. Specific protein–protein interactions determine the order of proteins within a multiprotein chain, and thereby the order in which chemically distinct monomers are added to the growing polyketide product. Here we investigate the evolutionary and molecular origins of protein interaction specificity. We focus on the short, conserved N- and C-terminal docking domains that mediate interactions between modular PKS proteins. Our computational analysis, which combines protein sequence data with experimental protein interaction data, reveals a hierarchical interaction specificity code. PKS docking domains are descended from a single ancestral interacting pair, but have split into three phylogenetic classes that are mutually noninteracting. Specificity within one such compatibility class is determined by a few key residues, which can be used to define compatibility subclasses. We identify these residues using a novel, highly sensitive co-evolution detection algorithm called CRoSS (correlated residues of statistical significance). The residue pairs selected by CRoSS are involved in direct physical interactions in a docked-domain NMR structure. A single PKS system can use docking domain pairs from multiple classes, as well as domain pairs from multiple subclasses of any given class. The termini of individual proteins are frequently shuffled, but docking domain pairs straddling two interacting proteins are linked as an evolutionary module. The hierarchical and modular organization of the specificity code is intimately related to the processes by which bacteria generate new PKS pathways. Biomolecular interactions can be extraordinarily specific. In many instances, a protein can select its single correct binding partner from among a large array of closely related candidates. For polyketide synthases (PKSs), a family of bacterial enzymes, such specificity is essential. Like workers on an assembly line, PKSs function as multiprotein chains, each enzyme modifying its substrate before passing it along to the next. And like a well-designed jigsaw puzzle, the overall multiprotein chain is correctly ordered precisely because each component protein can only bind to specific nearest neighbors. A PKS multiprotein chain is held together by sticky “head” and “tail” domains found at either end of each protein, the head of one protein binding to the tail of the next. We looked for patterns in the amino-acid sequences of these domains that could explain why certain head–tail pairs bind, while others do not. We discovered that heads and tails each come in three very different varieties. Mismatched head–tail pairs do not bind at all, while the binding of a matching head–tail pair is governed by the amino acids found at a few key positions on the physical interface between these domains.
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Affiliation(s)
- Mukund Thattai
- National Centre for Biological Sciences, Bangalore, India.
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37
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Abstract
This review chronicles the synergistic growth of the fields of fatty acid and polyketide synthesis over the last century. In both animal fatty acid synthases and modular polyketide synthases, similar catalytic elements are covalently linked in the same order in megasynthases. Whereas in fatty acid synthases the basic elements of the design remain immutable, guaranteeing the faithful production of saturated fatty acids, in the modular polyketide synthases, the potential of the basic design has been exploited to the full for the elaboration of a wide range of secondary metabolites of extraordinary structural diversity.
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Affiliation(s)
- Stuart Smith
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, California 94609, USA.
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Tae H, Kong EB, Park K. ASMPKS: an analysis system for modular polyketide synthases. BMC Bioinformatics 2007; 8:327. [PMID: 17764579 PMCID: PMC2008767 DOI: 10.1186/1471-2105-8-327] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 09/03/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Polyketides are secondary metabolites of microorganisms with diverse biological activities, including pharmacological functions such as antibiotic, antitumor and agrochemical properties. Polyketides are synthesized by serialized reactions of a set of enzymes called polyketide synthase(PKS)s, which coordinate the elongation of carbon skeletons by the stepwise condensation of short carbon precursors. Due to their importance as drugs, the volume of data on polyketides is rapidly increasing and creating a need for computational analysis methods for efficient polyketide research. Moreover, the increasing use of genetic engineering to research new kinds of polyketides requires genome wide analysis. RESULTS We describe a system named ASMPKS (Analysis System for Modular Polyketide Synthesis) for computational analysis of PKSs against genome sequences. It also provides overall management of information on modular PKS, including polyketide database construction, new PKS assembly, and chain visualization. ASMPKS operates on a web interface to construct the database and to analyze PKSs, allowing polyketide researchers to add their data to this database and to use it easily. In addition, the ASMPKS can predict functional modules for a protein sequence submitted by users, estimate the chemical composition of a polyketide synthesized from the modules, and display the carbon chain structure on the web interface. CONCLUSION ASMPKS has powerful computation features to aid modular PKS research. As various factors, such as starter units and post-processing, are related to polyketide biosynthesis, ASMPKS will be improved through further development for study of the factors.
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Affiliation(s)
- Hongseok Tae
- Information Technology Institute, SmallSoft Co., Ltd., Jang-Dong 59-5, Yusung-Gu, Daejeon 305-343, South Korea
- Deptartment of Computer Engineering, Chungnam National University, 220 Gung-dong, Daejeon 305-764, South Korea
| | - Eun-Bae Kong
- Deptartment of Computer Engineering, Chungnam National University, 220 Gung-dong, Daejeon 305-764, South Korea
| | - Kiejung Park
- Information Technology Institute, SmallSoft Co., Ltd., Jang-Dong 59-5, Yusung-Gu, Daejeon 305-343, South Korea
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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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Menzella HG, Carney JR, Santi DV. Rational design and assembly of synthetic trimodular polyketide synthases. ACTA ACUST UNITED AC 2007; 14:143-51. [PMID: 17317568 DOI: 10.1016/j.chembiol.2006.12.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 11/22/2006] [Accepted: 12/04/2006] [Indexed: 10/23/2022]
Abstract
Type I polyketide synthases (PKSs) consist of modules that add two-carbon units in polyketide backbones. Rearranging modules from different sources can yield novel enzymes that produce unnatural products, but the rules that govern module-module communication are still not well known. The construction and assay of hybrid bimodular units with synthetic PKS genes were recently reported. Here, we describe the rational design of trimodular PKSs by combining bimodular units. A cloning-expression system was developed to assemble and test 54 unnatural trimodular PKSs flanked by the loading module and the thioesterase from the erythromycin synthase. Remarkably, 96% of them produced the expected polyketide. The obtained results represent an important milestone toward the ultimate goal of making new bioactive polyketides by rational design. Additionally, these results show a path for the production of customized tetraketides by fermentation, which can be an important source of advanced intermediates to facilitate the synthesis of complex products.
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Chan YA, Boyne MT, Podevels AM, Klimowicz AK, Handelsman J, Kelleher NL, Thomas MG. Hydroxymalonyl-acyl carrier protein (ACP) and aminomalonyl-ACP are two additional type I polyketide synthase extender units. Proc Natl Acad Sci U S A 2006; 103:14349-54. [PMID: 16983083 PMCID: PMC1599966 DOI: 10.1073/pnas.0603748103] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Combinatorial biosynthesis of type I polyketide synthases is a promising approach for the generation of new structural derivatives of polyketide-containing natural products. A target of this approach has been to change the extender units incorporated into a polyketide backbone to alter the structure and activity of the natural product. One limitation to these efforts is that only four extender units were known: malonyl-CoA, methylmalonyl-CoA, ethylmalonyl-CoA, and methoxymalonyl-acyl carrier protein (ACP). The chemical attributes of these extender units are quite similar, with the exception of the potential hydrogen bonding interactions by the oxygen of the methoxy moiety. Furthermore, the incorporated extender units are not easily modified by using simple chemical approaches when combinatorial biosynthesis is coupled to semisynthetic chemistry. We recently proposed the existence of two additional extender units, hydroxymalonyl-ACP and aminomalonyl-ACP, involved in the biosynthesis of zwittermicin A. These extender units offer unique possibilities for combinatorial biosynthesis and semisynthetic chemistry because of the introduction of free hydroxyl and amino moieties into a polyketide structure. Here, we present the biochemical and mass spectral evidence for the formation of these extender units. This evidence shows the formation of ACP-linked extender units for polyketide synthesis. Interestingly, aminomalonyl-ACP formation involves enzymology typically found in nonribosomal peptide synthesis.
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Affiliation(s)
- Yolande A. Chan
- *Departments of Bacteriology and
- Microbiology Doctoral Training Program, University of Wisconsin, Madison, WI 53706; and
| | - Michael T. Boyne
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | | | | | - Jo Handelsman
- Plant Pathology and
- Microbiology Doctoral Training Program, University of Wisconsin, Madison, WI 53706; and
| | - Neil L. Kelleher
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | - Michael G. Thomas
- *Departments of Bacteriology and
- Microbiology Doctoral Training Program, University of Wisconsin, Madison, WI 53706; and
- To whom correspondence should be addressed. E-mail:
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42
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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: 1060] [Impact Index Per Article: 58.9] [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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Watanabe K, Hotta K, Praseuth AP, Koketsu K, Migita A, Boddy CN, Wang CCC, Oguri H, Oikawa H. Total biosynthesis of antitumor nonribosomal peptides in Escherichia coli. Nat Chem Biol 2006; 2:423-8. [PMID: 16799553 DOI: 10.1038/nchembio803] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 06/02/2006] [Indexed: 11/09/2022]
Abstract
Nonribosomal peptides (NRPs) are a class of microbial secondary metabolites that have a wide variety of medicinally important biological activities, such as antibiotic (vancomycin), immunosuppressive (cyclosporin A), antiviral (luzopeptin A) and antitumor (echinomycin and triostin A) activities. However, many microbes are not amenable to cultivation and require time-consuming empirical optimization of incubation conditions for mass production of desired secondary metabolites for clinical and commercial use. Therefore, a fast, simple system for heterologous production of natural products is much desired. Here we show the first example of the de novo total biosynthesis of biologically active forms of heterologous NRPs in Escherichia coli. Our system can serve not only as an effective and flexible platform for large-scale preparation of natural products from simple carbon and nitrogen sources, but also as a general tool for detailed characterizations and rapid engineering of biosynthetic pathways for microbial syntheses of novel compounds and their analogs.
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Affiliation(s)
- Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90033, USA
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Moffet DA, Khosla C, Cane DE. Modular polyketide synthases: Investigating intermodular communication using 6 deoxyerythronolide B synthase module 2. Bioorg Med Chem Lett 2006; 16:213-6. [PMID: 16213712 DOI: 10.1016/j.bmcl.2005.09.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2005] [Revised: 09/01/2005] [Accepted: 09/06/2005] [Indexed: 11/18/2022]
Abstract
A novel variant of 6-deoxyerythronolide B synthase (DEBS) module 2 was constructed to explore the balance between protein-protein-mediated intermodular channeling and intrinsic substrate specificity within DEBS. This construct, termed (N3)Mod2+TE, was co-incubated with a complementary, donor form of the same module, (N5)Mod2(C2), as well as with a mutant of (N5)Mod2(C2) with an inactive ketosynthase domain, in order to determine the extent of intermediate channeling versus substrate diffusion into the downstream module.
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Affiliation(s)
- David A Moffet
- Department of Chemistry, Box H, Brown University, Providence, RI 02912-9108, USA
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Abstract
The bacterial multienzyme polyketide synthases (PKSs) produce a diverse array of products that have been developed into medicines, including antibiotics and anticancer agents. The modular genetic architecture of these PKSs suggests that it might be possible to engineer the enzymes to produce novel drug candidates, a strategy known as 'combinatorial biosynthesis'. So far, directed engineering of modular PKSs has resulted in the production of more than 200 new polyketides, but key challenges remain before the potential of combinatorial biosynthesis can be fully realized.
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Affiliation(s)
- Kira J Weissman
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
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Hartung IV, Rude MA, Schnarr NA, Hunziker D, Khosla* C. Stereochemical assignment of intermediates in the rifamycin biosynthetic pathway by precursor-directed biosynthesis. J Am Chem Soc 2005; 127:11202-3. [PMID: 16089423 PMCID: PMC1360739 DOI: 10.1021/ja051430y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Natural and semisynthetic rifamycins are clinically important inhibitors of bacterial DNA-dependent RNA polymerase. Although the polyketide-nonribosomal peptide origin of the naphthalene core of rifamycin B is well established, the absolute and relative configuration of both stereocenters introduced by the first polyketide synthase module is obscured by aromatization of the naphthalene ring. To decode the stereochemistry of the rifamycin polyketide precursor, we synthesized all four diastereomers of the biosynthetic substrate for module 2 of the rifamycin synthetase in the form of their N-acetylcysteamine (SNAC) thioester. Only one diastereomer was turned over in vivo into rifamycin B, thus establishing the absolute and relative configuration of the native biosynthetic intermediates.
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Bode HB, Müller R. Der Einfluss bakterieller Genomik auf die Naturstoff-Forschung. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501080] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
"There's life in the old dog yet!" This adage also holds true for natural product research. After the era of natural products was declared to be over, because of the introduction of combinatorial synthesis techniques, natural product research has taken a surprising turn back towards a major field of pharmaceutical research. Current challenges, such as emerging multidrug-resistant bacteria, might be overcome by developments which combine genomic knowledge with applied biology and chemistry to identify, produce, and alter the structure of new lead compounds. Significant biological activity is reported much less frequently for synthetic compounds, a fact reflected in the large proportion of natural products and their derivatives in clinical use. This Review describes the impact of microbial genomics on natural products research, in particularly the search for new lead structures and their optimization. The limitations of this research are also discussed, thus allowing a look into future developments.
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Affiliation(s)
- Helge B Bode
- Institut für Pharmazeutische Biotechnologie, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany
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Menzella HG, Reid R, Carney JR, Chandran SS, Reisinger SJ, Patel KG, Hopwood DA, Santi DV. Combinatorial polyketide biosynthesis by de novo design and rearrangement of modular polyketide synthase genes. Nat Biotechnol 2005; 23:1171-6. [PMID: 16116420 DOI: 10.1038/nbt1128] [Citation(s) in RCA: 258] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 06/30/2005] [Indexed: 11/09/2022]
Abstract
Type I polyketide synthase (PKS) genes consist of modules approximately 3-6 kb long, which encode the structures of 2-carbon units in polyketide products. Alteration or replacement of individual PKS modules can lead to the biosynthesis of 'unnatural' natural products but existing techniques for this are time consuming. Here we describe a generic approach to the design of synthetic PKS genes where facile cassette assembly and interchange of modules and domains are facilitated by a repeated set of flanking restriction sites. To test the feasibility of this approach, we synthesized 14 modules from eight PKS clusters and associated them in 154 bimodular combinations spanning over 1.5-million bp of novel PKS gene sequences. Nearly half the combinations successfully mediated the biosynthesis of a polyketide in Escherichia coli, and all individual modules participated in productive bimodular combinations. This work provides a truly combinatorial approach for the production of polyketides.
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Affiliation(s)
- Hugo G Menzella
- Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, California 94545, USA
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Ginolhac A, Jarrin C, Robe P, Perrière G, Vogel TM, Simonet P, Nalin R. Type I polyketide synthases may have evolved through horizontal gene transfer. J Mol Evol 2005; 60:716-25. [PMID: 15909225 DOI: 10.1007/s00239-004-0161-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Accepted: 02/02/2005] [Indexed: 11/30/2022]
Abstract
Type I polyketide synthases (PKSI) are modular multidomain enzymes involved in the biosynthesis of many natural products of industrial interest. PKSI modules are minimally organized in three domains: ketosynthase (KS), acyltransferase (AT), and acyl carrier protein. The KS domain phylogeny of 23 PKSI clusters was determined. The results obtained suggest that many horizontal transfers of PKSI genes have occurred between actinomycetales species. Such gene transfers may explain the homogeneity and the robustness of the actinomycetales group since gene transfers between closely related species could mimic patterns generated by vertical inheritance. We suggest that the linearity and instability of actinomycetales chromosomes associated with their large quantity of genetic mobile elements have favored such horizontal gene transfers.
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Affiliation(s)
- Aurélien Ginolhac
- LibraGen S.A., Bâtiment Canal Biotech 1, 3 rue des Satellites, 31400, Toulouse, France.
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