1
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Ray KA, Saif N, Keatinge-Clay AT. Modular polyketide synthase ketosynthases collaborate with upstream dehydratases to install double bonds. Chem Commun (Camb) 2024; 60:8712-8715. [PMID: 39056119 PMCID: PMC11321453 DOI: 10.1039/d4cc03034f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024]
Abstract
A VMYH motif was determined to help ketosynthases in polyketide assembly lines select α,β-unsaturated intermediates from an equilibrium mediated by an upstream dehydratase. Alterations of this motif decreased ketosynthase selectivity within a model tetraketide synthase, most significantly when replaced by the TNGQ motif of ketosynthases that accept D-β-hydroxy intermediates.
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Affiliation(s)
- Katherine A Ray
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th St., Austin, TX 78712, USA.
| | - Nisha Saif
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th St., Austin, TX 78712, USA.
| | - Adrian T Keatinge-Clay
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th St., Austin, TX 78712, USA.
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2
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Ray KA, Lutgens JD, Bista R, Zhang J, Desai RR, Hirsch M, Miyazawa T, Cordova A, Keatinge-Clay AT. Assessing and harnessing updated polyketide synthase modules through combinatorial engineering. Nat Commun 2024; 15:6485. [PMID: 39090122 PMCID: PMC11294587 DOI: 10.1038/s41467-024-50844-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 07/23/2024] [Indexed: 08/04/2024] Open
Abstract
The modular nature of polyketide assembly lines and the significance of their products make them prime targets for combinatorial engineering. The recently updated module boundary has been successful for engineering short synthases, yet larger synthases constructed using the updated boundary have not been investigated. Here we describe our design and implementation of a BioBricks-like platform to rapidly construct 5 triketide, 25 tetraketide, and 125 pentaketide synthases to test every module combination of the pikromycin synthase. Anticipated products are detected from 60% of the triketide synthases, 32% of the tetraketide synthases, and 6.4% of the pentaketide synthases. We determine ketosynthase gatekeeping and module-skipping are the principal impediments to obtaining functional synthases. The platform is also employed to construct active hybrid synthases by incorporating modules from the erythromycin, spinosyn, and rapamycin assembly lines. The relaxed gatekeeping of a ketosynthase in the rapamycin synthase is especially encouraging in the quest to produce designer polyketides.
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Affiliation(s)
- Katherine A Ray
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Joshua D Lutgens
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Ramesh Bista
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jie Zhang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Ronak R Desai
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Melissa Hirsch
- Department of Chemistry, The University of Texas at Austin, Austin, TX, USA
| | - Takeshi Miyazawa
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Antonio Cordova
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Adrian T Keatinge-Clay
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
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3
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Hirsch M, Desai RR, Annaswamy S, Keatinge-Clay AT. Mutagenesis Supports AlphaFold Prediction of How Modular Polyketide Synthase Acyl Carrier Proteins Dock With Downstream Ketosynthases. Proteins 2024. [PMID: 39078105 DOI: 10.1002/prot.26733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 06/07/2024] [Accepted: 07/05/2024] [Indexed: 07/31/2024]
Abstract
The docking of an acyl carrier protein (ACP) domain with a downstream ketosynthase (KS) domain in each module of a polyketide synthase (PKS) helps ensure accurate biosynthesis. If the polyketide chain bound to the ACP has been properly modified by upstream processing enzymes and is compatible with gatekeeping residues in the KS tunnel, a transacylation reaction can transfer it from the 18.1-Å phosphopantetheinyl arm of the ACP to the reactive cysteine of the KS. AlphaFold-Multimer predicts a general interface for these transacylation checkpoints. Half of the solutions obtained for 50 ACP/KS pairs show the KS motif TxLGDP forming the first turn of an α-helix, as in reported structures, while half show it forming a type I β-turn not previously observed. Solutions with the latter conformation may represent how these domains are relatively positioned during the transacylation reaction, as the entrance to the KS active site is relatively open and the phosphopantetheinylated ACP serine and the reactive KS cysteine are relatively closer-17.2 versus 20.9 Å, on average. To probe the predicted interface, 20 mutations were made to KS surface residues within the model triketide lactone synthase P1-P6-P7. The activities of these mutants are consistent with the proposed interface.
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Affiliation(s)
- Melissa Hirsch
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Ronak R Desai
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Shreyas Annaswamy
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Adrian T Keatinge-Clay
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
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4
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Xiang C, Yao S, Wang R, Zhang L. Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain. Beilstein J Org Chem 2024; 20:1476-1485. [PMID: 38978744 PMCID: PMC11228615 DOI: 10.3762/bjoc.20.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 06/21/2024] [Indexed: 07/10/2024] Open
Abstract
Polyketides are a major class of natural products, including bioactive medicines such as erythromycin and rapamycin. They are often rich in stereocenters biosynthesized by the ketoreductase (KR) domain within the polyketide synthase (PKS) assembly line. Previous studies have identified conserved motifs in KR sequences that enable the bioinformatic prediction of product stereochemistry. However, the reliability and applicability of these prediction methods have not been thoroughly assessed. In this study, we conducted a comprehensive bioinformatic analysis of 1,762 KR sequences from cis-AT PKSs to reevaluate the residues involved in conferring stereoselectivity. Our findings indicate that the previously identified fingerprint motifs remain valid for KRs in β-modules from actinobacteria, but their reliability diminishes for KRs from other module types or taxonomic origins. Additionally, we have identified several new motifs that exhibit a strong correlation with the stereochemical outcomes of KRs. These updated fingerprint motifs for stereochemical prediction not only enhance our understanding of the enzymatic mechanisms governing stereocontrol but also facilitate accurate stereochemical prediction and genome mining of polyketides derived from modular cis-AT PKSs.
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Affiliation(s)
- Changjun Xiang
- Department of Chemistry, Fudan University, Shanghai 200433, China
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, China
| | - Shunyu Yao
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, China
| | - Ruoyu Wang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, China
| | - Lihan Zhang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310030, China
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5
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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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6
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Nava A, Roberts J, Haushalter RW, Wang Z, Keasling JD. Module-Based Polyketide Synthase Engineering for de Novo Polyketide Biosynthesis. ACS Synth Biol 2023; 12:3148-3155. [PMID: 37871264 PMCID: PMC10661043 DOI: 10.1021/acssynbio.3c00282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Indexed: 10/25/2023]
Abstract
Polyketide retrobiosynthesis, where the biosynthetic pathway of a given polyketide can be reversibly engineered due to the colinearity of the polyketide synthase (PKS) structure and function, has the potential to produce millions of organic molecules. Mixing and matching modules from natural PKSs is one of the routes to produce many of these molecules. Evolutionary analysis of PKSs suggests that traditionally used module boundaries may not lead to the most productive hybrid PKSs and that new boundaries around and within the ketosynthase domain may be more active when constructing hybrid PKSs. As this is still a nascent area of research, the generality of these design principles based on existing engineering efforts remains inconclusive. Recent advances in structural modeling and synthetic biology present an opportunity to accelerate PKS engineering by re-evaluating insights gained from previous engineering efforts with cutting edge tools.
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Affiliation(s)
- Alberto
A. Nava
- Joint
BioEnergy Institute, Lawrence Berkeley National
Laboratory, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Jacob Roberts
- Joint
BioEnergy Institute, Lawrence Berkeley National
Laboratory, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Bioengineering, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Robert W. Haushalter
- Joint
BioEnergy Institute, Lawrence Berkeley National
Laboratory, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zilong Wang
- Joint
BioEnergy Institute, Lawrence Berkeley National
Laboratory, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jay D. Keasling
- Joint
BioEnergy Institute, Lawrence Berkeley National
Laboratory, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Department
of Bioengineering, University of California,
Berkeley, Berkeley, California 94720, United States
- Center
for Synthetic Biochemistry, Shenzhen Institutes
for Advanced Technologies, Shenzhen 518055, P.R. China
- The
Novo
Nordisk Foundation Center for Biosustainability, Technical University Denmark, Kemitorvet, Building 220, Kongens Lyngby 2800, Denmark
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7
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Li F, Lin Z, Krug PJ, Catrow JL, Cox JE, Schmidt EW. Animal FAS-like polyketide synthases produce diverse polypropionates. Proc Natl Acad Sci U S A 2023; 120:e2305575120. [PMID: 37695909 PMCID: PMC10515154 DOI: 10.1073/pnas.2305575120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/01/2023] [Indexed: 09/13/2023] Open
Abstract
Animal cytoplasmic fatty acid synthase (FAS) represents a unique family of enzymes that are classically thought to be most closely related to fungal polyketide synthase (PKS). Recently, a widespread family of animal lipid metabolic enzymes has been described that bridges the gap between these two ubiquitous and important enzyme classes: the animal FAS-like PKSs (AFPKs). Although very similar in sequence to FAS enzymes that produce saturated lipids widely found in animals, AFPKs instead produce structurally diverse compounds that resemble bioactive polyketides. Little is known about the factors that bridge lipid and polyketide synthesis in the animals. Here, we describe the function of EcPKS2 from Elysia chlorotica, which synthesizes a complex polypropionate natural product found in this mollusc. EcPKS2 starter unit promiscuity potentially explains the high diversity of polyketides found in and among molluscan species. Biochemical comparison of EcPKS2 with the previously described EcPKS1 reveals molecular principles governing substrate selectivity that should apply to related enzymes encoded within the genomes of photosynthetic gastropods. Hybridization experiments combining EcPKS1 and EcPKS2 demonstrate the interactions between the ketoreductase and ketosynthase domains in governing the product outcomes. Overall, these findings enable an understanding of the molecular principles of structural diversity underlying the many molluscan polyketides likely produced by the diverse AFPK enzyme family.
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Affiliation(s)
- Feng Li
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT84112
| | - Zhenjian Lin
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT84112
| | - Patrick J. Krug
- Department of Biological Sciences, California State University, Los Angeles, CA90032
| | - J. Leon Catrow
- Metabolomics Core, Health Sciences Center, Salt Lake City, UT84112
| | - James E. Cox
- Metabolomics Core, Health Sciences Center, Salt Lake City, UT84112
- Department of Biochemistry, University of Utah, Salt Lake City, UT84112
| | - Eric W. Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT84112
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8
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Englund E, Schmidt M, Nava AA, Klass S, Keiser L, Dan Q, Katz L, Yuzawa S, Keasling JD. Biosensor Guided Polyketide Synthases Engineering for Optimization of Domain Exchange Boundaries. Nat Commun 2023; 14:4871. [PMID: 37573440 PMCID: PMC10423236 DOI: 10.1038/s41467-023-40464-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/28/2023] [Indexed: 08/14/2023] Open
Abstract
Type I modular polyketide synthases (PKSs) are multi-domain enzymes functioning like assembly lines. Many engineering attempts have been made for the last three decades to replace, delete and insert new functional domains into PKSs to produce novel molecules. However, inserting heterologous domains often destabilize PKSs, causing loss of activity and protein misfolding. To address this challenge, here we develop a fluorescence-based solubility biosensor that can quickly identify engineered PKSs variants with minimal structural disruptions. Using this biosensor, we screen a library of acyltransferase (AT)-exchanged PKS hybrids with randomly assigned domain boundaries, and we identify variants that maintain wild type production levels. We then probe each position in the AT linker region to determine how domain boundaries influence structural integrity and identify a set of optimized domain boundaries. Overall, we have successfully developed an experimentally validated, high-throughput method for making hybrid PKSs that produce novel molecules.
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Affiliation(s)
- Elias Englund
- Joint BioEnergy Institute, Emeryville, CA, USA
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Matthias Schmidt
- Joint BioEnergy Institute, Emeryville, CA, USA
- Institute of Applied Microbiology, Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
- Biological Systems and Engineering Division, Lawrence Berkeley National laboratory, Berkeley, CA, USA
| | - Alberto A Nava
- Joint BioEnergy Institute, Emeryville, CA, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Sarah Klass
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National laboratory, Berkeley, CA, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Leah Keiser
- Joint BioEnergy Institute, Emeryville, CA, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Qingyun Dan
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National laboratory, Berkeley, CA, USA
| | - Leonard Katz
- Joint BioEnergy Institute, Emeryville, CA, USA
- QB3, University of California, Berkeley, Berkeley, CA, USA
| | - Satoshi Yuzawa
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National laboratory, Berkeley, CA, USA
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
- Graduate school of Media and Governance, Keio University, Fujisawa, Kanagawa, Japan
| | - Jay D Keasling
- Joint BioEnergy Institute, Emeryville, CA, USA.
- Biological Systems and Engineering Division, Lawrence Berkeley National laboratory, Berkeley, CA, USA.
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA.
- QB3, University of California, Berkeley, Berkeley, CA, USA.
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA.
- Center for Biosustainability, Danish Technical University, Lyngby, Denmark.
- Center for Synthetic biochemistry, Institute for Synthetic biology, Shenzhen Institute of Advanced Technology, Shenzhen, China.
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9
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Ray KA, Lutgens JD, Bista R, Zhang J, Desai RR, Hirsch M, Miyazawa T, Cordova A, Keatinge-Clay AT. Assessing and harnessing updated polyketide synthase modules through combinatorial engineering. RESEARCH SQUARE 2023:rs.3.rs-3157617. [PMID: 37546965 PMCID: PMC10402262 DOI: 10.21203/rs.3.rs-3157617/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
The modular nature of polyketide assembly lines and the significance of their products make them prime targets for combinatorial engineering. While short synthases constructed using the recently updated module boundary have been shown to outperform those using the traditional boundary, larger synthases constructed using the updated boundary have not been investigated. Here we describe our design and implementation of a BioBricks-like platform to rapidly construct 5 triketide, 25 tetraketide, and 125 pentaketide synthases from the updated modules of the Pikromycin synthase. Every combinatorial possibility of modules 2-6 inserted between the first and last modules of the native synthase was constructed and assayed. Anticipated products were observed from 60% of the triketide synthases, 32% of the tetraketide synthases, and 6.4% of the pentaketide synthases. Ketosynthase gatekeeping and module-skipping were determined to be the principal impediments to obtaining functional synthases. The platform was also used to create functional hybrid synthases through the incorporation of modules from the Erythromycin, Spinosyn, and Rapamycin assembly lines. The relaxed gatekeeping observed from a ketosynthase in the Rapamycin synthase is especially encouraging in the quest to produce designer polyketides.
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Affiliation(s)
- Katherine A. Ray
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Joshua D. Lutgens
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Ramesh Bista
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Jie Zhang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Ronak R. Desai
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Melissa Hirsch
- Department of Chemistry, The University of Texas at Austin, Austin, TX
| | - Takeshi Miyazawa
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
| | - Antonio Cordova
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX
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10
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Jing G, Wenjun G, Yi W, Kepan X, Wen L, Tingting H, Zhiqiang C. Enhancing Enzyme Activity and Thermostability of Bacillus amyloliquefaciens Chitosanase BaCsn46A Through Saturation Mutagenesis at Ser196. Curr Microbiol 2023; 80:180. [PMID: 37046080 DOI: 10.1007/s00284-023-03281-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 03/21/2023] [Indexed: 04/14/2023]
Abstract
Chitosanase plays an important role in chitooligosaccharides (COS) production. We found that the chitosanase (BaCsn46A) of Bacillus amyloliquefacien was a good candidate for chitosan hydrolysis of COS. In order to further improve the enzyme properties of BaCsn46A, the S196 located near the active center was found to be a critical site impacts on enzyme properties by sequence alignment analysis. Herein, saturation mutation was carried out to study role of 196 site on BaCsn46A catalytic function. Compared with WT, the specific enzyme activity of S196A increased by 118.79%, and the thermostability of S196A was much higher than WT. In addition, we found that the enzyme activity of S196P was 2.41% of that of WT, indicating that the type of amino acid in 196 site could significant affect the catalytic activity and thermostability of BaCsn46A. After molecular docking analysis we found that the increase in hydrogen bonds and decrease in unfavorable bonds interacting with the substrate were the main reason for the change of enzyme properties which is valuable for future studies on Bacillus species chitosanase.
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Affiliation(s)
- Guo Jing
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
- Advanced Catalysis and Green Manufacturing Collaborative Innovation Center and Laboratory of Applied Microbiology, School of Pharmaceutical, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Gao Wenjun
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
| | - Wang Yi
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
| | - Xu Kepan
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
| | - Luo Wen
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
| | - Hong Tingting
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China
- Advanced Catalysis and Green Manufacturing Collaborative Innovation Center and Laboratory of Applied Microbiology, School of Pharmaceutical, Changzhou University, Changzhou, 213164, Jiangsu, China
| | - Cai Zhiqiang
- Laboratory of Applied Microbiology, School of Biological and Food Engineering, Changzhou University, Changzhou Jiangsu, 213164, China.
- Advanced Catalysis and Green Manufacturing Collaborative Innovation Center and Laboratory of Applied Microbiology, School of Pharmaceutical, Changzhou University, Changzhou, 213164, Jiangsu, China.
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11
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Dickinson MS, Miyazawa T, McCool RS, Keatinge-Clay AT. Priming enzymes from the pikromycin synthase reveal how assembly-line ketosynthases catalyze carbon-carbon chemistry. Structure 2022; 30:1331-1339.e3. [PMID: 35738283 PMCID: PMC9444953 DOI: 10.1016/j.str.2022.05.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/28/2022] [Accepted: 05/27/2022] [Indexed: 10/17/2022]
Abstract
The first domain of modular polyketide synthases (PKSs) is most commonly a ketosynthase (KS)-like enzyme, KSQ, that primes polyketide synthesis. Unlike downstream KSs that fuse α-carboxyacyl groups to growing polyketide chains, it performs an extension-decoupled decarboxylation of these groups to generate primer units. When Pik127, a model triketide synthase constructed from modules of the pikromycin synthase, was studied by cryoelectron microscopy (cryo-EM), the dimeric didomain comprised of KSQ and the neighboring methylmalonyl-selective acyltransferase (AT) dominated the class averages and yielded structures at 2.5- and 2.8-Å resolution, respectively. Comparisons with ketosynthases complexed with their substrates revealed the conformation of the (2S)-methylmalonyl-S-phosphopantetheinyl portion of KSQ and KS substrates prior to decarboxylation. Point mutants of Pik127 probed the roles of residues in the KSQ active site, while an AT-swapped version of Pik127 demonstrated that KSQ can also decarboxylate malonyl groups. Mechanisms for how KSQ and KS domains catalyze carbon-carbon chemistry are proposed.
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Affiliation(s)
- Miles S Dickinson
- Sauer Structural Biology Lab, The University of Texas at Austin, 102 E. 24th Street, Austin, TX 78712, USA
| | - Takeshi Miyazawa
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th Street, Austin, TX 78712, USA
| | - Ryan S McCool
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th Street, Austin, TX 78712, USA
| | - Adrian T Keatinge-Clay
- Department of Molecular Biosciences, The University of Texas at Austin, 100 E. 24th Street, Austin, TX 78712, USA.
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12
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Zhou W, Alharbi HA, Hummingbird E, Keatinge-Clay AT, Mahmud T. Functional Studies and Revision of the NFAT-133/TM-123 Biosynthetic Pathway in Streptomyces pactum. ACS Chem Biol 2022; 17:2039-2045. [PMID: 35904416 PMCID: PMC9391300 DOI: 10.1021/acschembio.2c00454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The biosynthetic gene cluster of NFAT-133, an inhibitor of the nuclear factor of activated T cells, was recently identified in Streptomyces pactum ATCC 27456. This cluster is conspicuous by its highly disordered noncollinear type I modular polyketide synthase (PKS) genes that encode PKSs with one module more than those expected for the heptaketide NFAT-133 biosynthesis. Thus, the major metabolite NFAT-133 was proposed to derive from an octaketide analogue, TM-123. Here, we report that further bioinformatic analysis and gene inactivation studies suggest that NFAT-133 is not derived from TM-123 but rather a product of programmed KS7 extension skipping of a nascent heptaketide from the PKS assembly line that produces TM-123. Furthermore, identification of NFAT-133/TM-123 analogues from mutants of the ATCC 27456 strain suggests that NftN (a putative dehydrogenase), NftE (a cytochrome P450), and NftG (a putative hydrolase/decarboxylase) function "in trans" during the polyketide chain assembly processes.
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Affiliation(s)
- Wei Zhou
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507 (USA)
| | - Hattan A. Alharbi
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507 (USA)
| | - Eshe Hummingbird
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507 (USA)
| | | | - Taifo Mahmud
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507 (USA)
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