1
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Zhao C, Slocum ST, Sherman DH, Ruotolo BT. Time-Resolved Ion Mobility-Mass Spectrometry Reveals Structural Transitions in the Disassembly of Modular Polyketide Syntheses. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:2136-2142. [PMID: 39038158 DOI: 10.1021/jasms.4c00181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
The type 1 polyketide synthase (PKS) assembly line uses its modular structure to produce polyketide natural products that form the basis of many pharmaceuticals. Currently, several cryoelectron microscopy (cryo-EM) structures of a multidomain PKS module have been constructed, but much remains to be learned. Here we utilize ion-mobility mass spectrometry (IM-MS) to record size and shape information and detect different conformational states of a 207 kDa didomain dimer comprised of ketosynthase (KS) and acyl transferase (AT), excised from full-length module. Furthermore, gas-phase stability differences between these different conformations are captured by collision induced unfolding (CIU) technology. Additionally, through tracking these forms as a function of time, we elucidate a detailed disassembly pathway for KS-AT dimers for the first time.
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Affiliation(s)
- Chunyi Zhao
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Samuel T Slocum
- Life Science Institute, Departments of Medicinal Chemistry, Chemistry and Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H Sherman
- Life Science Institute, Departments of Medicinal Chemistry, Chemistry and Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Buyachuihan L, Stegemann F, Grininger M. How Acyl Carrier Proteins (ACPs) Direct Fatty Acid and Polyketide Biosynthesis. Angew Chem Int Ed Engl 2024; 63:e202312476. [PMID: 37856285 DOI: 10.1002/anie.202312476] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/21/2023]
Abstract
Megasynthases, such as type I fatty acid and polyketide synthases (FASs and PKSs), are multienzyme complexes responsible for producing primary metabolites and complex natural products. Fatty acids (FAs) and polyketides (PKs) are built by assembling and modifying small acyl moieties in a stepwise manner. A central aspect of FA and PK biosynthesis involves the shuttling of substrates between the domains of the multienzyme complex. This essential process is mediated by small acyl carrier proteins (ACPs). The ACPs must navigate to the different catalytic domains within the multienzyme complex in a particular order to guarantee the fidelity of the biosynthesis pathway. However, the precise mechanisms underlying ACP-mediated substrate shuttling, particularly the factors contributing to the programming of the ACP movement, still need to be fully understood. This Review illustrates the current understanding of substrate shuttling, including concepts of conformational and specificity control, and proposes a confined ACP movement within type I megasynthases.
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Affiliation(s)
- Lynn Buyachuihan
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Franziska Stegemann
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
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3
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Guzman KM, Cogan DP, Brodsky KL, Soohoo AM, Li X, Sevillano N, Mathews II, Nguyen KP, Craik CS, Khosla C. Discovery and Characterization of Antibody Probes of Module 2 of the 6-Deoxyerythronolide B Synthase. Biochemistry 2023. [PMID: 37184546 DOI: 10.1021/acs.biochem.3c00156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fragment antigen-binding domains of antibodies (Fabs) are powerful probes of structure-function relationships of assembly line polyketide synthases (PKSs). We report the discovery and characterization of Fabs interrogating the structure and function of the ketosynthase-acyltransferase (KS-AT) core of Module 2 of the 6-deoxyerythronolide B synthase (DEBS). Two Fabs (AC2 and BB1) were identified to potently inhibit the catalytic activity of Module 2. Both AC2 and BB1 were found to modulate ACP-mediated reactions catalyzed by this module, albeit by distinct mechanisms. AC2 primarily affects the rate (kcat), whereas BB1 increases the KM of an ACP-mediated reaction. A third Fab, AA5, binds to the KS-AT fragment of DEBS Module 2 without altering either parameter; it is phenotypically reminiscent of a previously characterized Fab, 1B2, shown to principally recognize the N-terminal helical docking domain of DEBS Module 3. Crystal structures of AA5 and 1B2 bound to the KS-AT fragment of Module 2 were solved to 2.70 and 2.65 Å resolution, respectively, and revealed entirely distinct recognition features of the two antibodies. The new tools and insights reported here pave the way toward advancing our understanding of the structure-function relationships of DEBS Module 2, arguably the most well-studied module of an assembly line PKS.
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Affiliation(s)
- Katarina M Guzman
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Dillon P Cogan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Krystal L Brodsky
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander M Soohoo
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Xiuyuan Li
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Natalia Sevillano
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Khanh P Nguyen
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, United States
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Sarafan ChEM-H, Stanford University, Stanford, California 94305, United States
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4
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Mamada SS, Nainu F, Masyita A, Frediansyah A, Utami RN, Salampe M, Emran TB, Lima CMG, Chopra H, Simal-Gandara J. Marine Macrolides to Tackle Antimicrobial Resistance of Mycobacterium tuberculosis. Mar Drugs 2022; 20:691. [PMID: 36355013 PMCID: PMC9697125 DOI: 10.3390/md20110691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 09/01/2023] Open
Abstract
Tuberculosis has become a major health problem globally. This is worsened by the emergence of resistant strains of Mycobacterium tuberculosis showing ability to evade the effectiveness of the current antimycobacterial therapies. Therefore, the efforts carried out to explore new entities from many sources, including marine, are critical. This review summarizes several marine-derived macrolides that show promising activity against M. tuberculosis. We also provide information regarding the biosynthetic processes of marine macrolides, including the challenges that are usually experienced in this process. As most of the studies reporting the antimycobacterial activities of the listed marine macrolides are based on in vitro studies, the future direction should consider expanding the trials to in vivo and clinical trials. In addition, in silico studies should also be explored for a quick screening on marine macrolides with potent activities against mycobacterial infection. To sum up, macrolides derived from marine organisms might become therapeutical options for tackling antimycobacterial resistance of M. tuberculosis.
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Affiliation(s)
- Sukamto S. Mamada
- Department of Pharmacy, Faculty of Pharmacy, Hasanuddin University, Makassar 90245, Indonesia
| | - Firzan Nainu
- Department of Pharmacy, Faculty of Pharmacy, Hasanuddin University, Makassar 90245, Indonesia
| | - Ayu Masyita
- Department of Pharmaceutical Science and Technology, Faculty of Pharmacy, Hasanuddin University, Makassar 90245, Indonesia
- Research Center for Vaccine and Drugs, Research Organization for Health, National Research and Innovation Agency (BRIN), Tangerang Selatan 15318, Indonesia
| | - Andri Frediansyah
- Research Center for Food Technology and Processing, National Research and Innovation Agency (BRIN), Yogyakarta 55861, Indonesia
| | - Rifka Nurul Utami
- Department of Pharmaceutical Science and Technology, Faculty of Pharmacy, Hasanuddin University, Makassar 90245, Indonesia
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK
| | | | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong 4381, Bangladesh
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka 1207, Bangladesh
| | | | - Hitesh Chopra
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Jesus Simal-Gandara
- Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain
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5
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Gan Y, Bai M, Lin X, Liu K, Huang B, Jiang X, Liu Y, Gao C. Improvement of macrolactins production by the genetic adaptation of Bacillus siamensis A72 to saline stress via adaptive laboratory evolution. Microb Cell Fact 2022; 21:147. [PMID: 35854349 PMCID: PMC9294813 DOI: 10.1186/s12934-022-01871-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Macrolactins, a type of macrolide antibiotic, are toxic to the producer strains. As such, its level is usually maintained below the lethal concentration during the fermentation process. To improve the production of macrolactins, we applied adaptive laboratory evolution technology to engineer a saline-resistant mutant strain. The hypothesis that strains with saline resistance show improved macrolactins production was investigated. RESULTS Using saline stress as a selective pressure, we engineered a mutant strain with saline resistance coupled with enhanced macrolactins production within 60 days using a self-made device. As compared with the parental strain, the evolved strain produced macrolactins with 11.93% improvement in non-saline stress fermentation medium containing 50 g/L glucose, when the glucose concentration increased to 70 g/L, the evolved strain produced macrolactins with 71.04% improvement. RNA sequencing and metabolomics results revealed that amino acid metabolism was involved in the production of macrolactins in the evolved strain. Furthermore, genome sequencing of the evolved strain revealed a candidate mutation, hisDD41Y, that was causal for the improved MLNs production, it was 3.42 times higher than the control in the overexpression hisDD41Y strain. Results revealed that saline resistance protected the producer strain from feedback inhibition of end-product (macrolide antibiotic), resulting in enhanced MLNs production. CONCLUSIONS In the present work, we successfully engineered a mutant strain with enhanced macrolactins production by adaptive laboratory evolution using saline stress as a selective pressure. Based on physiological, transcriptomic and genetic analysis, amino acid metabolism was found to benefit macrolactins production improvement. Our strategy might be applicable to improve the production of other kinds of macrolide antibiotics and other toxic compounds. The identification of the hisD mutation will allow for the deduction of metabolic engineering strategies in future research.
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Affiliation(s)
- Yuman Gan
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China.
| | - Meng Bai
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China
| | - Xiao Lin
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China
| | - Kai Liu
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China
| | - Bingyao Huang
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China
| | - Xiaodong Jiang
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China
| | - Yonghong Liu
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China.
| | - Chenghai Gao
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Guangxi, 530001, People's Republic of China.
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6
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Analysis of secondary metabolite gene clusters and chitin biosynthesis pathways of Monascus purpureus with high production of pigment and citrinin based on whole-genome sequencing. PLoS One 2022; 17:e0263905. [PMID: 35648754 PMCID: PMC9159588 DOI: 10.1371/journal.pone.0263905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/25/2022] [Indexed: 11/19/2022] Open
Abstract
Monascus is a filamentous fungus that is widely used for producing Monascus pigments in the food industry in Southeast Asia. While the development of bioinformatics has helped elucidate the molecular mechanism underlying metabolic engineering of secondary metabolite biosynthesis, the biological information on the metabolic engineering of the morphology of Monascus remains unclear. In this study, the whole genome of M. purpureus CSU-M183 strain was sequenced using combined single-molecule real-time DNA sequencing and next-generation sequencing platforms. The length of the genome assembly was 23.75 Mb in size with a GC content of 49.13%, 69 genomic contigs and encoded 7305 putative predicted genes. In addition, we identified the secondary metabolite biosynthetic gene clusters and the chitin synthesis pathway in the genome of the high pigment-producing M. purpureus CSU-M183 strain. Furthermore, it is shown that the expression levels of most Monascus pigment and citrinin clusters located genes were significantly enhanced via atmospheric room temperature plasma mutagenesis. The results provide a basis for understanding the secondary metabolite biosynthesis, and constructing the metabolic engineering of the morphology of Monascus.
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7
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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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8
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Cogan DP, Zhang K, Li X, Li S, Pintilie GD, Roh SH, Craik CS, Chiu W, Khosla C. Mapping the catalytic conformations of an assembly-line polyketide synthase module. Science 2021; 374:729-734. [PMID: 34735239 DOI: 10.1126/science.abi8358] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Dillon P Cogan
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Kaiming Zhang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xiuyuan Li
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Shanshan Li
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Grigore D Pintilie
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Soung-Hun Roh
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,Department of Biological Sciences, Institute of Molecular Biology & Genetics, Seoul National University, Seoul 151-742, Korea
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, CA 94158, USA
| | - Wah Chiu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,Division of CryoEM and Bioimaging, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.,Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford ChEM-H, Stanford, CA 94305, USA
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9
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Sharma V, Kaur R, Salwan R. Streptomyces: host for refactoring of diverse bioactive secondary metabolites. 3 Biotech 2021; 11:340. [PMID: 34221811 DOI: 10.1007/s13205-021-02872-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/31/2021] [Indexed: 12/22/2022] Open
Abstract
Microbial secondary metabolites are intensively explored due to their demands in pharmaceutical, agricultural and food industries. Streptomyces are one of the largest sources of secondary metabolites having diverse applications. In particular, the abundance of secondary metabolites encoding biosynthetic gene clusters and presence of wobble position in Streptomyces strains make it potential candidate as a native or heterologous host for secondary metabolite production including several cryptic gene clusters expression. Here, we have discussed the developments in Streptomyces strains genome mining, its exploration as a suitable host and application of synthetic biology for refactoring genetic systems for developing chassis for enhanced as well as novel secondary metabolites with reduced genome and cleaned background.
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Affiliation(s)
- Vivek Sharma
- University Centre for Research and Development, Chandigarh University, Gharuan, Mohali, Punjab 140413 India
| | - Randhir Kaur
- University Centre for Research and Development, Chandigarh University, Gharuan, Mohali, Punjab 140413 India
| | - Richa Salwan
- College of Horticulture and Forestry, Dr YS Parmar University of Horticulture and Forestry, Neri, Hamirpur, Himachal Pradesh 177001 India
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10
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Kalkreuter E, Bingham KS, Keeler AM, Lowell AN, Schmidt JJ, Sherman DH, Williams GJ. Computationally-guided exchange of substrate selectivity motifs in a modular polyketide synthase acyltransferase. Nat Commun 2021; 12:2193. [PMID: 33850151 PMCID: PMC8044089 DOI: 10.1038/s41467-021-22497-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
Polyketides, one of the largest classes of natural products, are often clinically relevant. The ability to engineer polyketide biosynthesis to produce analogs is critically important. Acyltransferases (ATs) of modular polyketide synthases (PKSs) catalyze the installation of malonyl-CoA extenders into polyketide scaffolds. ATs have been targeted extensively to site-selectively introduce various extenders into polyketides. Yet, a complete inventory of AT residues responsible for substrate selection has not been established, limiting the scope of AT engineering. Here, molecular dynamics simulations are used to prioritize ~50 mutations within the active site of EryAT6 from erythromycin biosynthesis, leading to identification of two previously unexplored structural motifs. Exchanging both motifs with those from ATs with alternative extender specificities provides chimeric PKS modules with expanded and inverted substrate specificity. Our enhanced understanding of AT substrate selectivity and application of this motif-swapping strategy are expected to advance our ability to engineer PKSs towards designer polyketides.
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Affiliation(s)
- Edward Kalkreuter
- Department of Chemistry, NC State University, Raleigh, NC, USA
- Comparative Medicine Institute, NC State University, Raleigh, NC, USA
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
| | - Kyle S Bingham
- Department of Chemistry, NC State University, Raleigh, NC, USA
- UNC Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Aaron M Keeler
- Department of Chemistry, NC State University, Raleigh, NC, USA
| | - Andrew N Lowell
- Life Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, Virginia Tech, Blacksburg, VA, USA
| | - Jennifer J Schmidt
- Life Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - David H Sherman
- Life Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Gavin J Williams
- Department of Chemistry, NC State University, Raleigh, NC, USA.
- Comparative Medicine Institute, NC State University, Raleigh, NC, USA.
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11
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Girija A, Vijayanathan M, Sreekumar S, Basheer J, Menon TG, Krishnankutty RE, Soniya EV. Harnessing the natural pool of polyketide and non-ribosomal peptide family: A route map towards novel drug development. Curr Mol Pharmacol 2021; 15:265-291. [PMID: 33745440 DOI: 10.2174/1874467214666210319145816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/10/2020] [Accepted: 12/31/2020] [Indexed: 11/22/2022]
Abstract
Emergence of communicable and non-communicable diseases possess health challenge to millions of people worldwide and is a major threat to the economic and social development in the coming century. The occurrence of recent pandemic, SARS-CoV-2 caused by lethal severe acute respiratory syndrome coronavirus 2 is one such example. Rapid research and development of drugs for the treatment and management of these diseases has been an incredibly challenging task for the pharmaceutical industry. Although, substantial focus has been made in the discovery of therapeutic compounds from natural sources having significant medicinal potential, their synthesis has shown a slow progress. Hence, the discovery of new targets by the application of the latest biotechnological and synthetic biology approaches is very much the need of the hour. Polyketides (PKs) and non-ribosomal peptides (NRPs) found in bacteria, fungi and plants are a large diverse family of natural products synthesized by two classes of enzymes: polyketide synthases (PKS) and non-ribosomal peptide synthetases (NRPS). These enzymes possess immense biomedical potential due to their simple architecture, catalytic capacity, as well as diversity. With the advent of latest in-silico and in-vitro strategies, these enzymes and their related metabolic pathways, if targeted, can contribute highly towards the biosynthesis of an array of potentially natural drug leads that have antagonist effects on biopolymers associated with various human diseases. In the face of the rising threat from the multidrug-resistant pathogens, this will further open new avenues for the discovery of novel and improved drugs by combining the natural and the synthetic approaches. This review discusses the relevance of polyketides and non-ribosomal peptides and the improvement strategies for the development of their derivatives and scaffolds, and how they will be beneficial to the future bioprospecting and drug discovery.
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Affiliation(s)
- Aiswarya Girija
- Transdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India.,Institute of Biological Environmental Rural Sciences (IBERS), Aberystwyth University, United Kingdom
| | - Mallika Vijayanathan
- Transdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India.,Biology Centre - Institute of Plant Molecular Biology, Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Sweda Sreekumar
- Transdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India.,Research Centre, University of Kerala, India
| | - Jasim Basheer
- School of Biosciences, Mahatma Gandhi University, PD Hills, Kottayam, Kerala, India.,Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacky University, Olomouc, Czech Republic
| | - Tara G Menon
- Transdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India
| | | | - Eppurathu Vasudevan Soniya
- Transdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India
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12
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Klaus M, Buyachuihan L, Grininger M. Ketosynthase Domain Constrains the Design of Polyketide Synthases. ACS Chem Biol 2020; 15:2422-2432. [PMID: 32786257 DOI: 10.1021/acschembio.0c00405] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Modular polyketide synthases (PKSs) produce complex, bioactive secondary metabolites in assembly line-like multistep reactions. Longstanding efforts to produce novel, biologically active compounds by recombining intact modules to new modular PKSs have mostly resulted in poorly active chimeras and decreased product yields. Recent findings demonstrate that the low efficiencies of modular chimeric PKSs also result from rate limitations in the transfer of the growing polyketide chain across the noncognate module:module interface and further processing of the non-native polyketide substrate by the ketosynthase (KS) domain. In this study, we aim at disclosing and understanding the low efficiency of chimeric modular PKSs and at establishing guidelines for modular PKSs engineering. To do so, we work with a bimodular PKS testbed and systematically vary substrate specificity, substrate identity, and domain:domain interfaces of the KS involved reactions. We observe that KS domains employed in our chimeric bimodular PKSs are bottlenecks with regards to both substrate specificity as well as interaction with the acyl carrier protein (ACP). Overall, our systematic study can explain in quantitative terms why early oversimplified engineering strategies based on the plain shuffling of modules mostly failed and why more recent approaches show improved success rates. We moreover identify two mutations of the KS domain that significantly increased turnover rates in chimeric systems and interpret this finding in mechanistic detail.
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Affiliation(s)
- Maja Klaus
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Lynn Buyachuihan
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
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13
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Dhakal D, Sohng JK, Pandey RP. Engineering actinomycetes for biosynthesis of macrolactone polyketides. Microb Cell Fact 2019; 18:137. [PMID: 31409353 PMCID: PMC6693128 DOI: 10.1186/s12934-019-1184-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 08/02/2019] [Indexed: 12/18/2022] Open
Abstract
Actinobacteria are characterized as the most prominent producer of natural products (NPs) with pharmaceutical importance. The production of NPs from these actinobacteria is associated with particular biosynthetic gene clusters (BGCs) in these microorganisms. The majority of these BGCs include polyketide synthase (PKS) or non-ribosomal peptide synthase (NRPS) or a combination of both PKS and NRPS. Macrolides compounds contain a core macro-lactone ring (aglycone) decorated with diverse functional groups in their chemical structures. The aglycon is generated by megaenzyme polyketide synthases (PKSs) from diverse acyl-CoA as precursor substrates. Further, post-PKS enzymes are responsible for allocating the structural diversity and functional characteristics for their biological activities. Macrolides are biologically important for their uses in therapeutics as antibiotics, anti-tumor agents, immunosuppressants, anti-parasites and many more. Thus, precise genetic/metabolic engineering of actinobacteria along with the application of various chemical/biological approaches have made it plausible for production of macrolides in industrial scale or generation of their novel derivatives with more effective biological properties. In this review, we have discussed versatile approaches for generating a wide range of macrolide structures by engineering the PKS and post-PKS cascades at either enzyme or cellular level in actinobacteria species, either the native or heterologous producer strains.
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Affiliation(s)
- Dipesh Dhakal
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
| | - Jae Kyung Sohng
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
- Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
| | - Ramesh Prasad Pandey
- Department of Life Science and Biochemical Engineering, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
- Department of Pharmaceutical Engineering and Biotechnology, Sun Moon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, 31460 Chungnam Republic of Korea
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14
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Xu Q, Zheng B, Pan L, Liu Q, Li Y. Practical Synthesis of β-Ketothioesters by Acid-Catalyzed Hydrolysis of Ketene N,S
-Acetals with Amino as the Leaving Group. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Qi Xu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis; Department of Chemistry; Northeast Normal University; 130024 Changchun China
| | - Baihui Zheng
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis; Department of Chemistry; Northeast Normal University; 130024 Changchun China
| | - Ling Pan
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis; Department of Chemistry; Northeast Normal University; 130024 Changchun China
| | - Qun Liu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis; Department of Chemistry; Northeast Normal University; 130024 Changchun China
| | - Yifei Li
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis; Department of Chemistry; Northeast Normal University; 130024 Changchun China
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15
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Klaus M, D’Souza AD, Nivina A, Khosla C, Grininger M. Engineering of Chimeric Polyketide Synthases Using SYNZIP Docking Domains. ACS Chem Biol 2019; 14:426-433. [PMID: 30682239 DOI: 10.1021/acschembio.8b01060] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Engineering of assembly line polyketide synthases (PKSs) to produce novel bioactive compounds has been a goal for over 20 years. The apparent modularity of PKSs has inspired many engineering attempts in which entire modules or single domains were exchanged. In recent years, it has become evident that certain domain-domain interactions are evolutionarily optimized and, if disrupted, cause a decrease of the overall turnover rate of the chimeric PKS. In this study, we compared different types of chimeric PKSs in order to define the least invasive interface and to expand the toolbox for PKS engineering. We generated bimodular chimeric PKSs in which entire modules were exchanged, while either retaining a covalent linker between heterologous modules or introducing a noncovalent docking domain, or SYNZIP domain, mediated interface. These chimeric systems exhibited non-native domain-domain interactions during intermodular polyketide chain translocation. They were compared to otherwise equivalent bimodular PKSs in which a noncovalent interface was introduced between the condensing and processing parts of a module, resulting in non-native domain interactions during the extender unit acylation and polyketide chain elongation steps of their catalytic cycles. We show that the natural PKS docking domains can be efficiently substituted with SYNZIP domains and that the newly introduced noncovalent interface between the condensing and processing parts of a module can be harnessed for PKS engineering. Additionally, we established SYNZIP domains as a new tool for engineering PKSs by efficiently bridging non-native interfaces without perturbing PKS activity.
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Affiliation(s)
- Maja Klaus
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
- Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - Alicia D. D’Souza
- Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - Aleksandra Nivina
- Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - Chaitan Khosla
- Departments of Chemistry and Chemical Engineering and Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
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16
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Moretto L, Heylen R, Holroyd N, Vance S, Broadhurst RW. Modular type I polyketide synthase acyl carrier protein domains share a common N-terminally extended fold. Sci Rep 2019; 9:2325. [PMID: 30787330 PMCID: PMC6382882 DOI: 10.1038/s41598-019-38747-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/15/2018] [Indexed: 11/09/2022] Open
Abstract
Acyl carrier protein (ACP) domains act as interaction hubs within modular polyketide synthase (PKS) systems, employing specific protein-protein interactions to present acyl substrates to a series of enzyme active sites. Many domains from the multimodular PKS that generates the toxin mycolactone display an unusually high degree of sequence similarity, implying that the few sites which vary may do so for functional reasons. When domain boundaries based on prior studies were used to prepare two isolated ACP segments from this system for studies of their interaction properties, one fragment adopted the expected tertiary structure, but the other failed to fold, despite sharing a sequence identity of 49%. Secondary structure prediction uncovered a previously undetected helical region (H0) that precedes the canonical helix-bundle ACP topology in both cases. This article reports the NMR solution structures of two N-terminally extended mycolactone mACP constructs, mH0ACPa and mH0ACPb, both of which possess an additional α-helix that behaves like a rigid component of the domain. The interactions of these species with a phosphopantetheinyl transferase and a ketoreductase domain are unaffected by the presence of H0, but a shorter construct that lacks the H0 region is shown to be substantially less thermostable than mH0ACPb. Bioinformatics analysis suggests that the extended H0-ACP motif is present in 98% of type I cis-acyltransferase PKS chain-extension modules. The polypeptide linker that connects an H0-ACP motif to the preceding domain must therefore be ~12 residues shorter than previously thought, imposing strict limits on ACP-mediated substrate delivery within and between PKS modules.
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Affiliation(s)
- Luisa Moretto
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Smålandsgatan-24, 392 34, Kalmar, Sweden
| | - Rachel Heylen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Natalie Holroyd
- Department of Medical Physics and Bioengineering, University College London, London, WC1E 6BT, UK
| | - Steven Vance
- Crescendo Biologics Ltd, Meditrina Building 260, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - R William Broadhurst
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK.
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17
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Wang Z, Bagde SR, Zavala G, Matsui T, Chen X, Kim CY. De Novo Design and Implementation of a Tandem Acyl Carrier Protein Domain in a Type I Modular Polyketide Synthase. ACS Chem Biol 2018; 13:3072-3077. [PMID: 30354045 DOI: 10.1021/acschembio.8b00896] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During polyketide and fatty acid biosynthesis, the growing acyl chain is attached to the acyl carrier protein via a thioester linkage. The acyl carrier protein interacts with other enzymes that perform chain elongation and chain modification on the bound acyl chain. Most type I polyketide synthases and fatty acid synthases contain only one acyl carrier protein. However, polyunsaturated fatty acid synthases from deep-sea bacteria contain anywhere from two to nine acyl carrier proteins. Recent studies have shown that this tandem acyl carrier protein feature is responsible for the unusually high fatty acid production rate of deep-sea bacteria. To investigate if a similar strategy can be used to increase the production rate of type I polyketide synthases, a 3×ACP domain was rationally designed and genetically installed in module 6 of 6-deoxyerythronolide B synthase, which is a prototypical type I modular polyketide synthase that naturally harbors just one acyl carrier protein. This modification resulted in an ∼2.5-fold increase in the total amount of polyketide produced in vitro, demonstrating that installing a tandem acyl carrier domain in a type I polyketide synthase is an effective strategy for enhancing the rate of polyketide natural product biosynthesis.
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Affiliation(s)
- Zilong Wang
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
- Department of Biological Sciences, National University of Singapore, 117543 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Centre for Life Sciences, National University of Singapore, 119077 Singapore
| | - Saket R. Bagde
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Gerardo Zavala
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, 14 2575 Sand Hill Road, MS69, Menlo Park, California 94025, United States
| | - Xi Chen
- College of Chemistry and Materials Science, Northwest University, 1 Xue Fu Avenue, Xi’an 710127, People’s Republic of China
| | - Chu-Young Kim
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
- Border Biomedical Research Center, The University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
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18
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Guzmán-Chávez F, Zwahlen RD, Bovenberg RAL, Driessen AJM. Engineering of the Filamentous Fungus Penicillium chrysogenum as Cell Factory for Natural Products. Front Microbiol 2018; 9:2768. [PMID: 30524395 PMCID: PMC6262359 DOI: 10.3389/fmicb.2018.02768] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/29/2018] [Indexed: 12/14/2022] Open
Abstract
Penicillium chrysogenum (renamed P. rubens) is the most studied member of a family of more than 350 Penicillium species that constitute the genus. Since the discovery of penicillin by Alexander Fleming, this filamentous fungus is used as a commercial β-lactam antibiotic producer. For several decades, P. chrysogenum was subjected to a classical strain improvement (CSI) program to increase penicillin titers. This resulted in a massive increase in the penicillin production capacity, paralleled by the silencing of several other biosynthetic gene clusters (BGCs), causing a reduction in the production of a broad range of BGC encoded natural products (NPs). Several approaches have been used to restore the ability of the penicillin production strains to synthetize the NPs lost during the CSI. Here, we summarize various re-activation mechanisms of BGCs, and how interference with regulation can be used as a strategy to activate or silence BGCs in filamentous fungi. To further emphasize the versatility of P. chrysogenum as a fungal production platform for NPs with potential commercial value, protein engineering of biosynthetic enzymes is discussed as a tool to develop de novo BGC pathways for new NPs.
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Affiliation(s)
- Fernando Guzmán-Chávez
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.,Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Reto D Zwahlen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.,Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Roel A L Bovenberg
- Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.,DSM Biotechnology Centre, Delft, Netherlands
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.,Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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19
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Li X, Sevillano N, La Greca F, Hsu J, Mathews II, Matsui T, Craik CS, Khosla C. Discovery and Characterization of a Thioesterase-Specific Monoclonal Antibody That Recognizes the 6-Deoxyerythronolide B Synthase. Biochemistry 2018; 57:6201-6208. [PMID: 30289692 DOI: 10.1021/acs.biochem.8b00886] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Assembly line polyketide synthases (PKSs) are large multimodular enzymes responsible for the biosynthesis of diverse antibiotics in bacteria. Structural and mechanistic analysis of these megasynthases can benefit from the discovery of reagents that recognize individual domains or linkers in a site-specific manner. Monoclonal antibodies not only have proven themselves as premier tools in analogous applications but also have the added benefit of constraining the conformational flexibility of their targets in unpredictable but often useful ways. Here we have exploited a library based on the naïve human antibody repertoire to discover a Fab (3A6) that recognizes the terminal thioesterase (TE) domain of the 6-deoxyerythronolide B synthase with high specificity. Biochemical assays were used to verify that 3A6 binding does not inhibit enzyme turnover. The co-crystal structure of the TE-3A6 complex was determined at 2.45 Å resolution, resulting in atomic characterization of this protein-protein recognition mechanism. Fab binding had minimal effects on the structural integrity of the TE. In turn, these insights were used to interrogate via small-angle X-ray scattering the solution-phase conformation of 3A6 complexed to a catalytically competent PKS module and bimodule. Altogether, we have developed a high-affinity monoclonal antibody tool that recognizes the TE domain of the 6-deoxyerythronolide B synthase while maintaining its native function.
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Affiliation(s)
| | - Natalia Sevillano
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
| | - Florencia La Greca
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
| | | | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Tsutomu Matsui
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
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20
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Dodge GJ, Maloney FP, Smith JL. Protein-protein interactions in "cis-AT" polyketide synthases. Nat Prod Rep 2018; 35:1082-1096. [PMID: 30188553 PMCID: PMC6207950 DOI: 10.1039/c8np00058a] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to the end of 2018 Polyketides are a valuable source of bioactive and clinically important molecules. The biosynthesis of these chemically complex molecules has led to the discovery of equally complex polyketide synthase (PKS) pathways. Crystallography has yielded snapshots of individual catalytic domains, di-domains, and multi-domains from a variety of PKS megasynthases, and cryo-EM studies have provided initial views of a PKS module in a series of defined biochemical states. Here, we review the structural and biochemical results that shed light on the protein-protein interactions critical to catalysis by PKS systems with an embedded acyltransferase. Interactions include those that occur both within and between PKS modules, as well as with accessory enzymes.
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Affiliation(s)
- Greg J Dodge
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA 48109.
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21
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Musiol-Kroll EM, Wohlleben W. Acyltransferases as Tools for Polyketide Synthase Engineering. Antibiotics (Basel) 2018; 7:antibiotics7030062. [PMID: 30022008 PMCID: PMC6164871 DOI: 10.3390/antibiotics7030062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 07/14/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Polyketides belong to the most valuable natural products, including diverse bioactive compounds, such as antibiotics, anticancer drugs, antifungal agents, immunosuppressants and others. Their structures are assembled by polyketide synthases (PKSs). Modular PKSs are composed of modules, which involve sets of domains catalysing the stepwise polyketide biosynthesis. The acyltransferase (AT) domains and their “partners”, the acyl carrier proteins (ACPs), thereby play an essential role. The AT loads the building blocks onto the “substrate acceptor”, the ACP. Thus, the AT dictates which building blocks are incorporated into the polyketide structure. The precursor- and occasionally the ACP-specificity of the ATs differ across the polyketide pathways and therefore, the ATs contribute to the structural diversity within this group of complex natural products. Those features make the AT enzymes one of the most promising tools for manipulation of polyketide assembly lines and generation of new polyketide compounds. However, the AT-based PKS engineering is still not straightforward and thus, rational design of functional PKSs requires detailed understanding of the complex machineries. This review summarizes the attempts of PKS engineering by exploiting the AT attributes for the modification of polyketide structures. The article includes 253 references and covers the most relevant literature published until May 2018.
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Affiliation(s)
- Ewa Maria Musiol-Kroll
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
| | - Wolfgang Wohlleben
- 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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Synthetic biology of polyketide synthases. ACTA ACUST UNITED AC 2018; 45:621-633. [DOI: 10.1007/s10295-018-2021-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/03/2018] [Indexed: 12/31/2022]
Abstract
Abstract
Complex reduced polyketides represent the largest class of natural products that have applications in medicine, agriculture, and animal health. This structurally diverse class of compounds shares a common methodology of biosynthesis employing modular enzyme systems called polyketide synthases (PKSs). The modules are composed of enzymatic domains that share sequence and functional similarity across all known PKSs. We have used the nomenclature of synthetic biology to classify the enzymatic domains and modules as parts and devices, respectively, and have generated detailed lists of both. In addition, we describe the chassis (hosts) that are used to assemble, express, and engineer the parts and devices to produce polyketides. We describe a recently developed software tool to design PKS system and provide an example of its use. Finally, we provide perspectives of what needs to be accomplished to fully realize the potential that synthetic biology approaches bring to this class of molecules.
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23
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Li X, Sevillano N, La Greca F, Deis L, Liu YC, Deller MC, Mathews II, Matsui T, Cane DE, Craik CS, Khosla C. Structure-Function Analysis of the Extended Conformation of a Polyketide Synthase Module. J Am Chem Soc 2018; 140:6518-6521. [PMID: 29762030 DOI: 10.1021/jacs.8b02100] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Catalytic modules of assembly-line polyketide synthases (PKSs) have previously been observed in two very different conformations-an "extended" architecture and an "arch-shaped" architecture-although the catalytic relevance of neither has been directly established. By the use of a fully human naïve antigen-binding fragment (Fab) library, a high-affinity antibody was identified that bound to the extended conformation of a PKS module, as verified by X-ray crystallography and tandem size-exclusion chromatography-small-angle X-ray scattering (SEC-SAXS). Kinetic analysis proved that this antibody-stabilized module conformation was fully competent for catalysis of intermodular polyketide chain translocation as well as intramodular polyketide chain elongation and functional group modification of a growing polyketide chain. Thus, the extended conformation of a PKS module is fully competent for all of its essential catalytic functions.
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Affiliation(s)
| | - Natalia Sevillano
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
| | - Florencia La Greca
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
| | | | | | - Marc C Deller
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - David E Cane
- Department of Chemistry , Box H, Brown University , Providence , Rhode Island 02912-9108 , United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry , University of California San Francisco , San Francisco , California 94158 , United States
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24
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Zhao H, Diao Q, Yu H, Li T, Liao P, Hou D. FeCl3·6H2O-catalyzed synthesis of β-ketothioesters from chain α-oxo ketene dithioactals. Chem Res Chin Univ 2017. [DOI: 10.1007/s40242-017-7082-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Xie X, Garg A, Khosla C, Cane DE. Mechanism and Stereochemistry of Polyketide Chain Elongation and Methyl Group Epimerization in Polyether Biosynthesis. J Am Chem Soc 2017; 139:3283-3292. [PMID: 28157306 DOI: 10.1021/jacs.7b00278] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The polyketide synthases responsible for the biosynthesis of the polyether antibiotics nanchangmycin (1) and salinomycin (4) harbor a number of redox-inactive ketoreductase (KR0) domains that are implicated in the generation of C2-epimerized (2S)-2-methyl-3-ketoacyl-ACP intermediates. Evidence that the natural substrate for the polyether KR0 domains is, as predicted, a (2R)-2-methyl-3-ketoacyl-ACP intermediate, came from a newly developed coupled ketosynthase (KS)-ketoreductase (KR) assay that established that the decarboxylative condensation of methylmalonyl-CoA with S-propionyl-N-acetylcysteamine catalyzed by the Nan[KS1][AT1] didomain from module 1 of the nanchangmycin synthase generates exclusively the corresponding (2R)-2-methyl-3-ketopentanoyl-ACP (7a) product. In tandem equilibrium isotope exchange experiments, incubation of [2-2H]-(2R,3S)-2-methyl-3-hydroxypentanoyl-ACP (6a) with redox-active, epimerase-inactive EryKR6 from module 6 of the 6-deoxyerythronolide B synthase and catalytic quantities of NADP+ in the presence of redox-inactive, recombinant NanKR10 or NanKR50, from modules 1 and 5 of the nanchangmycin synthase, or recombinant SalKR70 from module 7 of the salinomycin synthase, resulted in first-order, time-dependent washout of deuterium from 6a. Control experiments confirmed that this washout was due to KR0-catalyzed isotope exchange of the reversibly generated, transiently formed oxidation product [2-2H]-(2R)-2-methyl-3-ketopentanoyl-ACP (7a), consistent with the proposed epimerase activity of each of the KR0 domains. Although they belong to the superfamily of short chain dehydrogenase-reductases, the epimerase-active KR0 domains from polyether synthases lack one or both residues of the conserved Tyr-Ser dyad that has previously been implicated in KR-catalyzed epimerizations.
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Affiliation(s)
- Xinqiang Xie
- Department of Chemistry, Brown University , Box H, Providence, Rhode Island 02912-9108, United States
| | - Ashish Garg
- Department of Chemistry, Brown University , Box H, Providence, Rhode Island 02912-9108, United States
| | - Chaitan Khosla
- Departments of Chemical Engineering, Chemistry, and Biochemistry, Stanford University , Stanford, California 94305, United States
| | - David E Cane
- Department of Chemistry, Brown University , Box H, Providence, Rhode Island 02912-9108, United States
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26
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Ad O, Thuronyi BW, Chang MCY. Elucidating the mechanism of fluorinated extender unit loading for improved production of fluorine-containing polyketides. Proc Natl Acad Sci U S A 2017; 114:E660-E668. [PMID: 28096394 PMCID: PMC5293041 DOI: 10.1073/pnas.1614196114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polyketides are a large family of bioactive natural products synthesized by polyketide synthase (PKS) enzyme complexes predominantly from acetate and propionate. Given the structural diversity of compounds produced using these two simple building blocks, there has been longstanding interest in engineering the incorporation of alternative extender units. We have been investigating the mechanism of fluorinated monomer insertion by three of the six different modules of the PKS involved in erythromycin biosynthesis (6-deoxyerythronolide B synthase, DEBS) to begin understanding the contribution of different steps, such as enzyme acylation, transacylation, C-C bond formation, and chain transfer, to the overall selectivity and efficiency of this process. In these studies, we observe that inactivation of a cis-acyltransferase (AT) domain to circumvent its native extender unit preference leads concurrently to a change of mechanism in which chain extension with fluorine-substituted extender units switches largely to an acyl carrier protein (ACP)-independent mode. This result suggests that the covalent linkage between the growing polyketide chain and the enzyme is lost in these cases, which would limit efficient chain elongation after insertion of a fluorinated monomer. However, use of a standalone trans-acting AT to complement modules with catalytically deficient AT domains leads to enzyme acylation with the fluoromalonyl-CoA extender unit. Formation of the canonical ACP-linked intermediate with fluoromalonyl-CoA allows insertion of fluorinated extender units at 43% of the yield of the wild-type system while also amplifying product yield in single chain-extension experiments and enabling multiple chain extensions to form multiply fluorinated products.
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Affiliation(s)
- Omer Ad
- Department of Chemistry, University of California, Berkeley, CA 94720-1460
| | - B W Thuronyi
- Department of Chemistry, University of California, Berkeley, CA 94720-1460
| | - Michelle C Y Chang
- Department of Chemistry, University of California, Berkeley, CA 94720-1460;
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-1460
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27
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Robbins T, Liu YC, Cane DE, Khosla C. Structure and mechanism of assembly line polyketide synthases. Curr Opin Struct Biol 2016; 41:10-18. [PMID: 27266330 PMCID: PMC5136517 DOI: 10.1016/j.sbi.2016.05.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 11/16/2022]
Abstract
Assembly line polyketide synthases (PKSs) are remarkable biosynthetic machines with considerable potential for structure-based engineering. Several types of protein-protein interactions, both within and between PKS modules, play important roles in the catalytic cycle of a multimodular PKS. Additionally, vectorial biosynthesis is enabled by the energetic coupling of polyketide chain elongation to the channeling of intermediates between successive modules. A combination of high-resolution analysis of smaller PKS components and lower resolution characterization of intact modules and bimodules has yielded insights into the structure and organization of a prototypical assembly line PKS. This review discusses our understanding of key structure-function relationships in this family of megasynthases, along with a recap of key unanswered questions in the field.
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Affiliation(s)
- Thomas Robbins
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States
| | - Yu-Chen Liu
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States
| | - David E Cane
- Department of Chemistry, Brown University, Providence, RI 02912-9108, United States
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States.
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28
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Ostrowski MP, Cane DE, Khosla C. Recognition of acyl carrier proteins by ketoreductases in assembly line polyketide synthases. J Antibiot (Tokyo) 2016; 69:507-10. [PMID: 27118242 PMCID: PMC4963262 DOI: 10.1038/ja.2016.41] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/08/2016] [Accepted: 03/13/2016] [Indexed: 01/22/2023]
Abstract
Ketoreductases (KRs) are the most widespread tailoring domains found in individual modules of assembly line polyketide synthases (PKSs), and are responsible for controlling the configurations of both the α-methyl and β-hydroxyl stereogenic centers in the growing polyketide chain. Because they recognize substrates that are covalently bound to acyl carrier proteins (ACPs) within the same PKS module, we sought to quantify the extent to which protein-protein recognition contributes to the turnover of these oxidoreductive enzymes using stand-alone domains from the 6-deoxyerythronolide B synthase (DEBS). Reduced 2-methyl-3-hydroxyacyl-ACP substrates derived from two enantiomeric acyl chains and four distinct ACP domains were synthesized and presented to four distinct KR domains. Two KRs, from DEBS modules 2 and 5, displayed little preference for oxidation of substrates tethered to their cognate ACP domains over those attached to the other ACP domains tested. In contrast, the KR from DEBS module 1 showed a ca. 10-50-fold preference for substrate attached to its native ACP domain, whereas the KR from DEBS module 6 actually displayed a ca. 10-fold preference for the ACP from DEBS module 5. Our findings suggest that recognition of the ACP by a KR domain is unlikely to affect the rate of native assembly line polyketide biosynthesis. In some cases, however, unfavorable KR-ACP interactions may suppress the rate of substrate processing when KR domains are swapped to construct hybrid PKS modules.
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Affiliation(s)
- Matthew P Ostrowski
- Departments of Chemistry and Chemical Engineering, Stanford University, Stanford, CA, USA
| | - David E Cane
- Department of Chemistry, Brown University, Providence, RI, USA
| | - Chaitan Khosla
- Departments of Chemistry and Chemical Engineering, Stanford University, Stanford, CA, USA
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29
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Xie X, Garg A, Keatinge-Clay AT, Khosla C, Cane DE. Epimerase and Reductase Activities of Polyketide Synthase Ketoreductase Domains Utilize the Same Conserved Tyrosine and Serine Residues. Biochemistry 2016; 55:1179-86. [PMID: 26863427 DOI: 10.1021/acs.biochem.6b00024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of the conserved active site tyrosine and serine residues in epimerization catalyzed by polyketide synthase ketoreductase (PKS KR) domains has been investigated. Both mutant and wild-type forms of epimerase-active KR domains, including the intrinsically redox-inactive EryKR3° and PicKR3° as well as redox-inactive mutants of EryKR1, were incubated with [2-(2)H]-(2R,3S)-2-methyl-3-hydroxypentanoyl-SACP ([2-(2)H]-2) and 0.05 equiv of NADP(+) in the presence of the redox-active, epimerase-inactive EryKR6 domain. The residual epimerase activity of each mutant was determined by tandem equilibrium isotope exchange, in which the first-order, time-dependent washout of isotope from 2 was monitored by liquid chromatography-tandem mass spectrometry with quantitation of the deuterium content of the diagnostic pantetheinate ejection fragment (4). Replacement of the active site Tyr or Ser residues, alone or together, significantly reduced the observed epimerase activity of each KR domain with minimal effect on substrate binding. Our results demonstrate that the epimerase and reductase activities of PKS KR domains share a common active site, with both reactions utilizing the same pair of Tyr and Ser residues.
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Affiliation(s)
- Xinqiang Xie
- Department of Chemistry, Box H, Brown University , Providence, Rhode Island 02912-9108, United States
| | - Ashish Garg
- Department of Chemistry, Box H, Brown University , Providence, Rhode Island 02912-9108, United States
| | - Adrian T Keatinge-Clay
- Departments of Molecular Biosciences and Chemistry, The University of Texas at Austin , 1 University Station A5300, Austin, Texas 78712-0165, United States
| | - Chaitan Khosla
- Departments of Chemical Engineering, Chemistry, and Biochemistry, Stanford University , Stanford, California 94305, United States
| | - David E Cane
- Department of Chemistry, Box H, Brown University , Providence, Rhode Island 02912-9108, United States
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30
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Lowry B, Li X, Robbins T, Cane DE, Khosla C. A Turnstile Mechanism for the Controlled Growth of Biosynthetic Intermediates on Assembly Line Polyketide Synthases. ACS CENTRAL SCIENCE 2016; 2:14-20. [PMID: 26878060 PMCID: PMC4731828 DOI: 10.1021/acscentsci.5b00321] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Indexed: 05/09/2023]
Abstract
Vectorial polyketide biosynthesis on an assembly line polyketide synthase is the most distinctive property of this family of biological machines, while providing the key conceptual tool for the bioinformatic decoding of new antibiotic pathways. We now show that the action of the entire assembly line is synchronized by a previously unrecognized turnstile mechanism that prevents the ketosynthase domain of each module from being acylated by a new polyketide chain until the product of the prior catalytic cycle has been passed to the downstream module from the corresponding acyl carrier protein domain. The turnstile is closed by virtue of tight coupling to the signature decarboxylative condensation reaction catalyzed by the ketosynthase domain of each polyketide synthase module. Reopening of the turnstile is coupled to the eventual chain translocation step that vacates the module. At the maximal rate of substrate turnover, one would expect the chain release step to initiate a cascade of chain translocation events that sequentially migrate back upstream, thereby repriming each module and setting up the assembly line for the next round of polyketide chain elongation.
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Affiliation(s)
- Brian Lowry
- Departments
of Chemistry and Chemical Engineering, Stanford
University, Stanford, California 94305, United States
| | - Xiuyuan Li
- Departments
of Chemistry and Chemical Engineering, Stanford
University, Stanford, California 94305, United States
| | - Thomas Robbins
- Departments
of Chemistry and Chemical Engineering, Stanford
University, Stanford, California 94305, United States
| | - David E. Cane
- Department
of Chemistry, Brown University, Providence, Rhode Island 02912-9108, United States
| | - Chaitan Khosla
- Departments
of Chemistry and Chemical Engineering, Stanford
University, Stanford, California 94305, United States
- E-mail: . Tel: (650) 723-6538
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31
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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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32
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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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33
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Chemler JA, Tripathi A, Hansen DA, O'Neil-Johnson M, Williams RB, Starks C, Park SR, Sherman DH. Evolution of Efficient Modular Polyketide Synthases by Homologous Recombination. J Am Chem Soc 2015; 137:10603-9. [PMID: 26230368 DOI: 10.1021/jacs.5b04842] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural scaffolds of many complex natural products are produced by multifunctional type I polyketide synthase (PKS) enzymes that operate as biosynthetic assembly lines. The modular nature of these mega-enzymes presents an opportunity to construct custom biocatalysts built in a lego-like fashion by inserting, deleting, or exchanging native or foreign domains to produce targeted variants of natural polyketides. However, previously engineered PKS enzymes are often impaired resulting in limited production compared to native systems. Here, we show a versatile method for generating and identifying functional chimeric PKS enzymes for synthesizing custom macrolactones and macrolides. PKS genes from the pikromycin and erythromycin pathways were hybridized in Saccharomyces cerevisiae to generate hybrid libraries. We used a 96-well plate format for plasmid purification, transformations, sequencing, protein expression, in vitro reactions and analysis of metabolite formation. Active chimeric enzymes were identified with new functionality. Streptomyces venezuelae strains that expressed these PKS chimeras were capable of producing engineered macrolactones. Furthermore, a macrolactone generated from selected PKS chimeras was fully functionalized into a novel macrolide analogue. This method permits the engineering of PKS pathways as modular building blocks for the production of new antibiotic-like molecules.
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Affiliation(s)
| | | | | | - Mark O'Neil-Johnson
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Russell B Williams
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Courtney Starks
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
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34
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Architecture of the polyketide synthase module: surprises from electron cryo-microscopy. Curr Opin Struct Biol 2015; 31:9-19. [PMID: 25791608 DOI: 10.1016/j.sbi.2015.02.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 01/16/2023]
Abstract
Modular polyketide synthases (PKS) produce a vast array of bioactive molecules that are the basis of many highly valued pharmaceuticals. The biosynthesis of these compounds is based on ordered assembly lines of multi-domain modules, each extending and modifying a specific chain-elongation intermediate before transfer to the next module for further processing. The first 3D structures of a full polyketide synthase module in different functional states were obtained recently by electron cryo-microscopy. The unexpected module architecture revealed a striking evolutionary divergence of the polyketide synthase compared to its metazoan fatty acid synthase homolog, as well as remarkable conformational rearrangements dependent on its biochemical state during the full catalytic cycle. The design and dynamics of the module are highly optimized for both catalysis and fidelity in the construction of complex, biologically active natural products.
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35
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36
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Abstract
This review covers a breakthrough in the structural biology of the gigantic modular polyketide synthases (PKS): the structural characterization of intact modules by single-particle cryo-electron microscopy and small-angle X-ray scattering.
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Affiliation(s)
- Kira J. Weissman
- Molecular and Structural Enzymology Group
- Université de Lorraine
- IMoPA
- UMR 7365
- Vandœuvre-lès-Nancy
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37
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Poust S, Hagen A, Katz L, Keasling JD. Narrowing the gap between the promise and reality of polyketide synthases as a synthetic biology platform. Curr Opin Biotechnol 2014; 30:32-9. [DOI: 10.1016/j.copbio.2014.04.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/09/2014] [Accepted: 04/11/2014] [Indexed: 11/27/2022]
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38
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Edwards AL, Matsui T, Weiss TM, Khosla C. Architectures of whole-module and bimodular proteins from the 6-deoxyerythronolide B synthase. J Mol Biol 2014; 426:2229-45. [PMID: 24704088 PMCID: PMC4284093 DOI: 10.1016/j.jmb.2014.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
Abstract
The 6-deoxyerythronolide B synthase (DEBS) is a prototypical assembly line polyketide synthase produced by the actinomycete Saccharopolyspora erythraea that synthesizes the macrocyclic core of the antibiotic erythromycin 6-deoxyerythronolide B. The megasynthase is a 2-MDa trimeric complex composed of three unique homodimers assembled from the gene products DEBS1, DEBS2, and DEBS3, which are housed within the erythromycin biosynthetic gene cluster. Each homodimer contains two clusters of catalytically independent enzymatic domains, each referred to as a module, which catalyzes one round of polyketide chain extension and modification. Modules are named sequentially to indicate the order in which they are utilized during synthesis of 6-deoxyerythronolide B. We report small-angle X-ray scattering (SAXS) analyses of a whole module and a bimodule from DEBS, as well as a set of domains for which high-resolution structures are available. In all cases, the solution state was probed under previously established conditions ensuring that each protein is catalytically active. SAXS data are consistent with atomic-resolution structures of DEBS fragments. Therefore, we used the available high-resolution structures of DEBS domains to model the architectures of the larger protein assemblies using rigid-body refinement. Our data support a model in which the third module of DEBS forms a disc-shaped structure capable of caging the acyl carrier protein domain proximal to each active site. The molecular envelope of DEBS3 is a thin elongated ellipsoid, and the results of rigid-body modeling suggest that modules 5 and 6 stack collinearly along the 2-fold axis of symmetry.
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Affiliation(s)
- Andrea L Edwards
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, 14 2575 Sand Hill Road, MS69, Menlo Park, CA 94025, USA
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, 14 2575 Sand Hill Road, MS69, Menlo Park, CA 94025, USA
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
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39
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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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40
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Gay D, You YO, Keatinge-Clay A, Cane DE. Structure and stereospecificity of the dehydratase domain from the terminal module of the rifamycin polyketide synthase. Biochemistry 2013; 52:8916-28. [PMID: 24274103 DOI: 10.1021/bi400988t] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RifDH10, the dehydratase domain from the terminal module of the rifamycin polyketide synthase, catalyzes the stereospecific syn dehydration of the model substrate (2S,3S)-2-methyl-3-hydroxypentanoyl-RifACP10, resulting in the exclusive formation of (E)-2-methyl-2-pentenoyl-RifACP10. RifDH10 does not dehydrate any of the other three diastereomeric, RifACP10-bound, diketide thioester substrates. On the other hand, when EryACP6, from the sixth module of the erythromycin polyketide synthase, is substituted for RifACP10, RifDH10 stereospecifically dehydrates only (2R,3R)-2-methyl-3-hydroxypentanoyl-EryACP6 to give exclusively (E)-2-methyl-2-pentenoyl-EryACP6, with no detectable dehydration of any of the other three diastereomeric, EryACP6-bound, diketides. An identical alteration in substrate diastereospecificity was observed for the corresponding N-acetylcysteamine or pantetheine thioester analogues, regardless of acyl chain length or substitution pattern. Incubation of (2RS)-2-methyl-3-ketopentanoyl-RifACP10 with the didomain reductase-dehydratase RifKR10-RifDH10 yielded (E)-2-methyl-2-pentenoyl-RifACP10, the expected product of syn dehydration of (2S,3S)-2-methyl-3-hydroxypentanoyl-RifACP10, while incubation with the corresponding EryACP6-bound substrate, (2RS)-2-methyl-3-ketopentanoyl-EryACP6, gave only the reduction product (2S,3S)-2-methyl-3-hydroxypentanoyl-EryACP6 with no detectable dehydration. These results establish the intrinsic syn dehydration stereochemistry and substrate diastereoselectivity of RifDH10 and highlight the critical role of the natural RifACP10 domain in chaperoning the proper recognition and processing of the natural ACP-bound undecaketide substrate. The 1.82 Å resolution structure of RifDH10 reveals the atomic-resolution details of the active site and allows modeling of the syn dehydration of the (2S,3S)-2-methyl-3-hydroxyacyl-RifACP10 substrate. These results suggest that generation of the characteristic cis double bond of the rifamycins occurs after formation of the full-length RifACP10-bound acyclic trans-unsaturated undecaketide intermediate, most likely during the subsequent macrolactamization catalyzed by the amide synthase RifF.
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Affiliation(s)
- Darren Gay
- Department of Chemistry and Biochemistry, The University of Texas at Austin , 1 University Station A5300, Austin, Texas 78712-0165, United States
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41
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Abstract
Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug-resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery.
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Affiliation(s)
- Bijan Zakeri
- Synthetic Biology Group, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Department of Electrical Engineering & Computer Science and Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- MIT Synthetic Biology Center, 500 Technology Square, Cambridge MA 02139, USA
| | - Timothy K. Lu
- Synthetic Biology Group, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Department of Electrical Engineering & Computer Science and Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- MIT Synthetic Biology Center, 500 Technology Square, Cambridge MA 02139, USA
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42
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Williams GJ. Engineering polyketide synthases and nonribosomal peptide synthetases. Curr Opin Struct Biol 2013; 23:603-12. [PMID: 23838175 DOI: 10.1016/j.sbi.2013.06.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 01/05/2023]
Abstract
Naturally occurring polyketides and nonribosomal peptides with broad and potent biological activities continue to inspire the discovery of new and improved analogs. The biosynthetic apparatus responsible for the construction of these natural products has been the target of intensive protein engineering efforts. Traditionally, engineering has focused on substituting individual enzymatic domains or entire modules with those of different building block specificity, or by deleting various enzymatic functions, in an attempt to generate analogs. This review highlights strategies based on site-directed mutagenesis of substrate binding pockets, semi-rational mutagenesis, and whole-gene random mutagenesis to engineer the substrate specificity, activity, and protein interactions of polyketide and nonribosomal peptide biosynthetic machinery.
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Affiliation(s)
- Gavin J Williams
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, United States.
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43
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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: 84] [Impact Index Per Article: 7.6] [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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44
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Dunn BJ, Cane DE, Khosla C. Mechanism and specificity of an acyltransferase domain from a modular polyketide synthase. Biochemistry 2013; 52:1839-41. [PMID: 23452124 PMCID: PMC3612939 DOI: 10.1021/bi400185v] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acyltransferase (AT) domains of modular polyketide synthases exercise tight control over the choice of α-carboxyacyl-CoA substrates, but the mechanistic basis for this specificity is unknown. We show that whereas the specificity for the electrophilic malonyl or methylmalonyl component is primarily expressed in the first half-reaction (formation of the acyl-enzyme intermediate), the second half-reaction shows comparable specificity for the acyl carrier protein that carries the nucleophilic pantetheine arm. We also show that currently used approaches for engineering AT domain specificity work mainly by degrading specificity for the natural substrate rather than by enhancing specificity for alternative substrates.
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Affiliation(s)
- Briana J. Dunn
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
| | - David E. Cane
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
- Department of Chemistry and Biochemistry, Stanford University, Stanford, California 94305
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45
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Koryakina I, McArthur J, Randall S, Draelos MM, Musiol EM, Muddiman DC, Weber T, Williams GJ. Poly specific trans-acyltransferase machinery revealed via engineered acyl-CoA synthetases. ACS Chem Biol 2013; 8:200-8. [PMID: 23083014 DOI: 10.1021/cb3003489] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyketide synthases construct polyketides with diverse structures and biological activities via the condensation of extender units and acyl thioesters. Although a growing body of evidence suggests that polyketide synthases might be tolerant to non-natural extender units, in vitro and in vivo studies aimed at probing and utilizing polyketide synthase specificity are severely limited to only a small number of extender units, owing to the lack of synthetic routes to a broad variety of acyl-CoA extender units. Here, we report the construction of promiscuous malonyl-CoA synthetase variants that can be used to synthesize a broad range of malonyl-CoA extender units substituted at the C2-position, several of which contain handles for chemoselective ligation and are not found in natural biosynthetic systems. We highlighted utility of these enzymes by probing the acyl-CoA specificity of several trans-acyltransferases, leading to the unprecedented discovery of poly specificity toward non-natural extender units, several of which are not found in naturally occurring biosynthetic pathways. These results reveal that polyketide biosynthetic machinery might be more tolerant to non-natural substrates than previously established, and that mutant synthetases are valuable tools for probing the specificity of biosynthetic machinery. Our data suggest new synthetic biology strategies for harnessing this promiscuity and enabling the regioselective modification of polyketides.
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Affiliation(s)
| | | | | | | | - Ewa M. Musiol
- Eberhard-Karls-Universität Tübingen, Interfakultäres Institut für
Mikrobiologie und Infektionsmedizin, Mikrobiologie/Biotechnologie,
Tübingen, Germany
| | | | - Tilmann Weber
- Eberhard-Karls-Universität Tübingen, Interfakultäres Institut für
Mikrobiologie und Infektionsmedizin, Mikrobiologie/Biotechnologie,
Tübingen, Germany
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46
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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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47
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Prasad G, Borketey LS, Lin TY, Schnarr NA. A mechanism-based fluorescence transfer assay for examining ketosynthase selectivity. Org Biomol Chem 2012; 10:6717-23. [PMID: 22806124 PMCID: PMC4232300 DOI: 10.1039/c2ob26008e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since their discovery, polyketide synthases have received massive attention from researchers hoping to harness their potential as a platform for generating new and improved therapeutics. Despite significant strides toward this end, inherent specificities within the enzymes responsible for polyketide production have severely limited these efforts. We have developed a mechanism-based, fluorescence transfer assay for a key enzyme component of all polyketide synthases, the ketosynthase domain. As demonstrated, this method can be used with both ketosynthase-containing didomains and full modules. As proof of principle, the ketosynthase domain from module 6 of the 6-deoxyerythronolide synthase is examined for its ability to accept a variety of simple thioester substrates. Consistent with its natural hexaketide substrate, we find that this ketosynthase prefers longer, α-branched thioesters and its ability to distinguish these structural features is quite remarkable. Substrate electronics are also tested via a variety of p-substituted aromatic groups. In all, we expect this technique to find considerable use in the field of polyketide biosynthesis and engineering due to its extraordinary simplicity and very distinct visible readout.
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Affiliation(s)
- Gitanjeli Prasad
- Department of Chemistry, University of Massachusetts, Amherst, 01003, USA
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48
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Crosby J, Crump MP. The structural role of the carrier protein--active controller or passive carrier. Nat Prod Rep 2012; 29:1111-37. [PMID: 22930263 DOI: 10.1039/c2np20062g] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Common to all FASs, PKSs and NRPSs is a remarkable component, the acyl or peptidyl carrier protein (A/PCP). These take the form of small individual proteins in type II systems or discrete folded domains in the multi-domain type I systems and are characterized by a fold consisting of three major α-helices and between 60-100 amino acids. This protein is central to these biosynthetic systems and it must bind and transport a wide variety of functionalized ligands as well as mediate numerous protein-protein interactions, all of which contribute to efficient enzyme turnover. This review covers the structural and biochemical characterization of carrier proteins, as well as assessing their interactions with different ligands, and other synthase components. Finally, their role as an emerging tool in biotechnology is discussed.
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Affiliation(s)
- John Crosby
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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49
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Jensen K, Niederkrüger H, Zimmermann K, Vagstad AL, Moldenhauer J, Brendel N, Frank S, Pöplau P, Kohlhaas C, Townsend CA, Oldiges M, Hertweck C, Piel J. Polyketide proofreading by an acyltransferase-like enzyme. ACTA ACUST UNITED AC 2012; 19:329-39. [PMID: 22444588 DOI: 10.1016/j.chembiol.2012.01.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/09/2011] [Accepted: 01/02/2012] [Indexed: 11/18/2022]
Abstract
Trans-acyltransferase polyketide synthases (trans-AT PKSs) are an important group of bacterial enzymes producing bioactive polyketides. One difference from textbook PKSs is the presence of one or more free-standing AT-like enzymes. While one homolog loads the PKS with malonyl units, the function of the second copy (AT2) was unknown. We studied the two ATs PedC and PedD involved in pederin biosynthesis in an uncultivated symbiont. PedD displayed malonyl- but not acetyltransferase activity toward various acyl carrier proteins (ACPs). In contrast, the AT2 PedC efficiently hydrolyzed acyl units bound to N-acetylcysteamine or ACP. It accepted substrates with various chain lengths and functionalizations but did not cleave malonyl-ACP. These data are consistent with the role of PedC in PKS proofreading, suggesting a similar function for other AT2 homologs and providing strategies for polyketide titer improvement and biosynthetic investigations.
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Affiliation(s)
- Katja Jensen
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, 53121 Bonn, Germany
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50
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Liew CW, Nilsson M, Chen MW, Sun H, Cornvik T, Liang ZX, Lescar J. Crystal structure of the acyltransferase domain of the iterative polyketide synthase in enediyne biosynthesis. J Biol Chem 2012; 287:23203-15. [PMID: 22589546 DOI: 10.1074/jbc.m112.362210] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biosynthesis of the enediyne natural product dynemicin in Micromonospora chersina is initiated by DynE8, a highly reducing iterative type I polyketide synthase that assembles polyketide intermediates from the acetate units derived solely from malonyl-CoA. To understand the substrate specificity and the evolutionary relationship between the acyltransferase (AT) domains of DynE8, fatty acid synthase, and modular polyketide synthases, we overexpressed a 44-kDa fragment of DynE8 (hereafter named AT(DYN10)) encompassing its entire AT domain and the adjacent linker domain. The crystal structure at 1.4 Å resolution unveils a α/β hydrolase and a ferredoxin-like subdomain with the Ser-His catalytic dyad located in the cleft between the two subdomains. The linker domain also adopts a α/β fold abutting the AT catalytic domain. Co-crystallization with malonyl-CoA yielded a malonyl-enzyme covalent complex that most likely represents the acyl-enzyme intermediate. The structure explains the preference for malonyl-CoA with a conserved arginine orienting the carboxylate group of malonate and several nonpolar residues that preclude α-alkyl malonyl-CoA binding. Co-crystallization with acetyl-CoA revealed two noncovalently bound acetates generated by the enzymatic hydrolysis of acetyl-CoA that acts as an inhibitor for DynE8. This suggests that the AT domain can upload the acyl groups from either malonyl-CoA or acetyl-CoA onto the catalytic Ser(651) residue. However, although the malonyl group can be transferred to the acyl carrier protein domain, transfer of the acetyl group to the acyl carrier protein domain is suppressed. Local structural differences may account for the different stability of the acyl-enzyme intermediates.
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Affiliation(s)
- Chong Wai Liew
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
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