1
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Rogers AWL, Radlinski LC, Nguyen H, Tiffany CR, Carvalho TP, Masson HLP, Goodson ML, Bechtold L, Yamazaki K, Liou MJ, Miller BM, Mahan SP, Young BM, Demars AM, Gretler SR, Larabi AB, Lee JY, Bays DJ, Tsolis RM, Bäumler AJ. Salmonella re-engineers the intestinal environment to break colonization resistance in the presence of a compositionally intact microbiota. Cell Host Microbe 2024:S1931-3128(24)00284-1. [PMID: 39181125 DOI: 10.1016/j.chom.2024.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/29/2024] [Accepted: 07/29/2024] [Indexed: 08/27/2024]
Abstract
The gut microbiota prevents harmful microbes from entering the body, a function known as colonization resistance. The enteric pathogen Salmonella enterica serovar (S.) Typhimurium uses its virulence factors to break colonization resistance through unknown mechanisms. Using metabolite profiling and genetic analysis, we show that the initial rise in luminal pathogen abundance was powered by a combination of aerobic respiration and mixed acid fermentation of simple sugars, such as glucose, which resulted in their depletion from the metabolome. The initial rise in the abundance of the pathogen in the feces coincided with a reduction in the cecal concentrations of acetate and butyrate and an increase in epithelial oxygenation. Notably, these changes in the host environment preceded changes in the microbiota composition. We conclude that changes in the host environment can weaken colonization resistance even in the absence of overt compositional changes in the gut microbiota.
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Affiliation(s)
- Andrew W L Rogers
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Lauren C Radlinski
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Henry Nguyen
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Connor R Tiffany
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Thaynara Parente Carvalho
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Hugo L P Masson
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Michael L Goodson
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Lalita Bechtold
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Kohei Yamazaki
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA; Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Aomori, Japan
| | - Megan J Liou
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Brittany M Miller
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Scott P Mahan
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Briana M Young
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Aurore M Demars
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Sophie R Gretler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Anaïs B Larabi
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Jee-Yon Lee
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Derek J Bays
- Department of Internal Medicine, Division of Infectious Diseases, School of Medicine, University of California at Davis, One Shields Avenue, Sacramento, CA 95817, USA
| | - Renee M Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA.
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2
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Sword TT, Dinglasan JLN, Abbas GSK, Barker JW, Spradley ME, Greene ER, Gooden DS, Emrich SJ, Gilchrist MA, Doktycz MJ, Bailey CB. Profiling expression strategies for a type III polyketide synthase in a lysate-based, cell-free system. Sci Rep 2024; 14:12983. [PMID: 38839808 PMCID: PMC11153635 DOI: 10.1038/s41598-024-61376-w] [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: 12/16/2023] [Accepted: 05/06/2024] [Indexed: 06/07/2024] Open
Abstract
Some of the most metabolically diverse species of bacteria (e.g., Actinobacteria) have higher GC content in their DNA, differ substantially in codon usage, and have distinct protein folding environments compared to tractable expression hosts like Escherichia coli. Consequentially, expressing biosynthetic gene clusters (BGCs) from these bacteria in E. coli often results in a myriad of unpredictable issues with regard to protein expression and folding, delaying the biochemical characterization of new natural products. Current strategies to achieve soluble, active expression of these enzymes in tractable hosts can be a lengthy trial-and-error process. Cell-free expression (CFE) has emerged as a valuable expression platform as a testbed for rapid prototyping expression parameters. Here, we use a type III polyketide synthase from Streptomyces griseus, RppA, which catalyzes the formation of the red pigment flaviolin, as a reporter to investigate BGC refactoring techniques. We applied a library of constructs with different combinations of promoters and rppA coding sequences to investigate the synergies between promoter and codon usage. Subsequently, we assess the utility of cell-free systems for prototyping these refactoring tactics prior to their implementation in cells. Overall, codon harmonization improves natural product synthesis more than traditional codon optimization across cell-free and cellular environments. More importantly, the choice of coding sequences and promoters impact protein expression synergistically, which should be considered for future efforts to use CFE for high-yield protein expression. The promoter strategy when applied to RppA was not completely correlated with that observed with GFP, indicating that different promoter strategies should be applied for different proteins. In vivo experiments suggest that there is correlation, but not complete alignment between expressing in cell free and in vivo. Refactoring promoters and/or coding sequences via CFE can be a valuable strategy to rapidly screen for catalytically functional production of enzymes from BCGs, which advances CFE as a tool for natural product research.
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Affiliation(s)
- Tien T Sword
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Jaime Lorenzo N Dinglasan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Ghaeath S K Abbas
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA
- School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - J William Barker
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Madeline E Spradley
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Elijah R Greene
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Damian S Gooden
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Scott J Emrich
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, USA
- Department of Electrical Engineering and Computer Science, University of Tennessee-Knoxville, Knoxville, TN, USA
- Department of Ecology and Evolutionary Biology, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Michael A Gilchrist
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, USA
- Department of Ecology and Evolutionary Biology, University of Tennessee-Knoxville, Knoxville, TN, USA
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, USA.
| | - Constance B Bailey
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, USA.
- Graduate School of Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, USA.
- School of Chemistry, University of Sydney, Sydney, NSW, Australia.
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3
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Sword TT, Dinglasan JLN, Abbas GS, William Barker J, Spradley ME, Greene ER, Gooden DS, Emrich SJ, Gilchrist MA, Doktycz MJ, Bailey CB. Profiling Expression Strategies for a Type III Polyketide Synthase in a Lysate-Based, Cell-free System. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569483. [PMID: 38077034 PMCID: PMC10705458 DOI: 10.1101/2023.11.30.569483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Some of the most metabolically diverse species of bacteria (e.g., Actinobacteria) have higher GC content in their DNA, differ substantially in codon usage, and have distinct protein folding environments compared to tractable expression hosts like Escherichia coli. Consequentially, expressing biosynthetic gene clusters (BGCs) from these bacteria in E. coli frequently results in a myriad of unpredictable issues with protein expression and folding, delaying the biochemical characterization of new natural products. Current strategies to achieve soluble, active expression of these enzymes in tractable hosts, such as BGC refactoring, can be a lengthy trial-and-error process. Cell-free expression (CFE) has emerged as 1) a valuable expression platform for enzymes that are challenging to synthesize in vivo, and as 2) a testbed for rapid prototyping that can improve cellular expression. Here, we use a type III polyketide synthase from Streptomyces griseus, RppA, which catalyzes the formation of the red pigment flaviolin, as a reporter to investigate BGC refactoring techniques. We synergistically tune promoter and codon usage to improve flaviolin production from cell-free expressed RppA. We then assess the utility of cell-free systems for prototyping these refactoring tactics prior to their implementation in cells. Overall, codon harmonization improves natural product synthesis more than traditional codon optimization across cell-free and cellular environments. Refactoring promoters and/or coding sequences via CFE can be a valuable strategy to rapidly screen for catalytically functional production of enzymes from BCGs. By showing the coordinators between CFE versus in vivo expression, this work advances CFE as a tool for natural product research.
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Affiliation(s)
- Tien T. Sword
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Jaime Lorenzo N. Dinglasan
- Biosciences Division, Oak Ridge National Laboratory (Oak Ridge, TN USA)
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville Knoxville (Knoxville, TN USA)
| | - Ghaeath S.K. Abbas
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
- University of Sydney, School of Chemistry (Sydney, NSW, Australia)
| | - J. William Barker
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Madeline E. Spradley
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Elijah R. Greene
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Damian S. Gooden
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Scott J. Emrich
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville Knoxville (Knoxville, TN USA)
- Department of Electrical Engineering and Computer Science, University of Tennessee-Knoxville (Knoxville, TN USA)
- Department of Ecology & Evolutionary Biology, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Michael A. Gilchrist
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville Knoxville (Knoxville, TN USA)
- Department of Ecology & Evolutionary Biology, University of Tennessee-Knoxville (Knoxville, TN USA)
| | - Mitchel J. Doktycz
- Biosciences Division, Oak Ridge National Laboratory (Oak Ridge, TN USA)
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville Knoxville (Knoxville, TN USA)
| | - Constance B. Bailey
- Department of Chemistry, University of Tennessee-Knoxville (Knoxville, TN USA)
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville Knoxville (Knoxville, TN USA)
- University of Sydney, School of Chemistry (Sydney, NSW, Australia)
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4
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Miano A, Rychel K, Lezia A, Sastry A, Palsson B, Hasty J. High-resolution temporal profiling of E. coli transcriptional response. Nat Commun 2023; 14:7606. [PMID: 37993418 PMCID: PMC10665441 DOI: 10.1038/s41467-023-43173-7] [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: 07/22/2023] [Accepted: 11/02/2023] [Indexed: 11/24/2023] Open
Abstract
Understanding how cells dynamically adapt to their environment is a primary focus of biology research. Temporal information about cellular behavior is often limited by both small numbers of data time-points and the methods used to analyze this data. Here, we apply unsupervised machine learning to a data set containing the activity of 1805 native promoters in E. coli measured every 10 minutes in a high-throughput microfluidic device via fluorescence time-lapse microscopy. Specifically, this data set reveals E. coli transcriptome dynamics when exposed to different heavy metal ions. We use a bioinformatics pipeline based on Independent Component Analysis (ICA) to generate insights and hypotheses from this data. We discovered three primary, time-dependent stages of promoter activation to heavy metal stress (fast, intermediate, and steady). Furthermore, we uncovered a global strategy E. coli uses to reallocate resources from stress-related promoters to growth-related promoters following exposure to heavy metal stress.
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Affiliation(s)
- Arianna Miano
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA.
| | - Kevin Rychel
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Andrew Lezia
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Anand Sastry
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Bernhard Palsson
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs, Lyngby, Denmark
| | - Jeff Hasty
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Synthetic Biology Institute, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
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5
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Amrofell MB, Moon TS. Characterizing a Propionate Sensor in E. coli Nissle 1917. ACS Synth Biol 2023; 12:1868-1873. [PMID: 37220256 PMCID: PMC10865894 DOI: 10.1021/acssynbio.3c00138] [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] [Indexed: 05/25/2023]
Abstract
Short-chain fatty acids (SCFAs) are commonly found in the large intestine, but generally not in the small intestine, and influence microbiome composition and host physiology. Thus, synthetic biologists are interested in developing engineered probiotics capable of in situ detection of SCFAs as biogeography or disease sensors. One SCFA, propionate, is both sensed and consumed by E. coli. Here, we utilize the E. coli transcription factor PrpR, sensitive to the propionate-derived metabolite (2S,3S)-2-methylcitrate, and its cognate promoter PprpBCDE to detect extracellular propionate with the probiotic chassis bacterium E. coli Nissle 1917. We identify that PrpR-PprpBCDE displays stationary phase leakiness and transient bimodality, and we explain these observations through evolutionary rationales and deterministic modeling, respectively. Our results will help researchers build biogeographically sensitive genetic circuits.
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Affiliation(s)
- Matthew B. Amrofell
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Lous, MO, USA 63130
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Lous, MO, USA 63130
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, 63130, USA
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6
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Serebrinsky-Duek K, Barra M, Danino T, Garrido D. Engineered Bacteria for Short-Chain-Fatty-Acid-Repressed Expression of Biotherapeutic Molecules. Microbiol Spectr 2023; 11:e0004923. [PMID: 36939337 PMCID: PMC10101121 DOI: 10.1128/spectrum.00049-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/20/2023] [Indexed: 03/21/2023] Open
Abstract
Short-chain fatty acids (SCFA) such as propionate and butyrate are critical metabolites produced by the gut microbiota. Microbiome dysbiosis resulting in altered SCFA profiles is associated with certain diseases, including inflammatory bowel diseases (IBD), characterized by a reduction in butyrate concentration and active intestinal inflammation. There is an increasing interest in the use of engineered bacteria as diagnostic and therapeutic tools for gut diseases. In this study, we developed genetic circuits capable of sensing SCFA concentrations to build biosensors that express a response protein (superfolder green fluorescent protein [sfGFP]) in amounts inversely proportional to the SCFA concentration. We also built biotherapeutics expressing the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) using the same logic. The propionate biotherapeutic expressed larger amounts of mouse GM-CSF in the absence of propionate. The butyrate biotherapeutics presented the expected behavior only at the beginning of the kinetics and an accelerated response in the absence of butyrate. Overall, these genetic systems may function as complementary diagnostic tools for measuring SCFAs and as delivery vehicles for biotherapeutic molecules. IMPORTANCE Short-chain fatty acids are key molecules produced by the gut microbiome. Their concentrations are altered in certain diseases. Here, we created molecular biosensors that quantify the absence of propionate and butyrate, using logic "NOT" gates and bacterial promoters. Finally, we show that these genetic systems could be useful for the delivery of therapeutic molecules in the gut, in the absence of these acids.
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Affiliation(s)
- Kineret Serebrinsky-Duek
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maria Barra
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tal Danino
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Daniel Garrido
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
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7
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Lebovich M, Andrews LB. Surveying the Genetic Design Space for Transcription Factor-Based Metabolite Biosensors: Synthetic Gamma-Aminobutyric Acid and Propionate Biosensors in E. coli Nissle 1917. Front Bioeng Biotechnol 2022; 10:938056. [PMID: 36091463 PMCID: PMC9452892 DOI: 10.3389/fbioe.2022.938056] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/22/2022] [Indexed: 11/25/2022] Open
Abstract
Engineered probiotic bacteria have been proposed as a next-generation strategy for noninvasively detecting biomarkers in the gastrointestinal tract and interrogating the gut-brain axis. A major challenge impeding the implementation of this strategy has been the difficulty to engineer the necessary whole-cell biosensors. Creation of transcription factor-based biosensors in a clinically-relevant strain often requires significant tuning of the genetic parts and gene expression to achieve the dynamic range and sensitivity required. Here, we propose an approach to efficiently engineer transcription-factor based metabolite biosensors that uses a design prototyping construct to quickly assay the gene expression design space and identify an optimal genetic design. We demonstrate this approach using the probiotic bacterium Escherichia coli Nissle 1917 (EcN) and two neuroactive gut metabolites: the neurotransmitter gamma-aminobutyric acid (GABA) and the short-chain fatty acid propionate. The EcN propionate sensor, utilizing the PrpR transcriptional activator from E. coli, has a large 59-fold dynamic range and >500-fold increased sensitivity that matches biologically-relevant concentrations. Our EcN GABA biosensor uses the GabR transcriptional repressor from Bacillus subtilis and a synthetic GabR-regulated promoter created in this study. This work reports the first known synthetic microbial whole-cell biosensor for GABA, which has an observed 138-fold activation in EcN at biologically-relevant concentrations. Using this rapid design prototyping approach, we engineer highly functional biosensors for specified in vivo metabolite concentrations that achieve a large dynamic range and high output promoter activity upon activation. This strategy may be broadly useful for accelerating the engineering of metabolite biosensors for living diagnostics and therapeutics.
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Affiliation(s)
- Matthew Lebovich
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
- Biotechnology Training Program, University of Massachusetts Amherst, Amherst, MA, United States
| | - Lauren B. Andrews
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
- Biotechnology Training Program, University of Massachusetts Amherst, Amherst, MA, United States
- Molecular and Cellular Biology Graduate, Program University of Massachusetts Amherst, Amherst, MA, United States
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8
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Jaishankar J, Keshav A, Jayaram B, Chavan S, Srivastava P. Characterization of divergent promoters PmaiA and Phyd from Gordonia: Co-expression and regulation by CRP. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194843. [PMID: 35840055 DOI: 10.1016/j.bbagrm.2022.194843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Divergent promoters are often responsible for controlling gene expression of related genes of the same pathway or for coordinating regulation at different time points. There are relatively few reports on characterization of divergent promoters in bacteria. In the present study, microarray profiling was carried out to analyze gene expression during growth of Gordonia sp. IITR100, which led to the identification of 35 % of adjacent gene candidates that are divergently transcribed. We focus here on the in-depth characterization of one such pair of genes. Two divergent promoters, PmaiA and Phyd, drive the expression of genes encoding maleate cis-trans isomerase (maiA) and hydantoinase (hyd), respectively. Our findings reveal asymmetric promoter activity with higher activity in the reverse orientation (Phyd) as compared to the forward orientation (PmaiA). Minimal promoter region for each orientation was identified by deletion mapping. Deletion of a 5'-untranslated region of each gene resulted in an increase in promoter activity. A putative binding site for CRP (Catabolite Repressor Protein) transcription regulator was also identified in the 80 bp common regulatory region between the -35 hexamers of the two promoters. The results of this study suggest that CRP-mediated repression of PmaiA occurs only in the cells grown in glucose. Phyd, on the other hand, is not repressed by CRP. However, deletion of the CRP binding site located between -95 to -110 upstream to the transcription start site of the maiA gene resulted in increased activity of PmaiA and decreased activity of Phyd. A single CRP binding site, therefore, affects the two promoters differently.
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Affiliation(s)
- Jananee Jaishankar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Aditi Keshav
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Bijjiga Jayaram
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Sourabh Chavan
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India
| | - Preeti Srivastava
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi 110016, India.
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9
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Chin JHC, Samian MR, Normi YM. Characterization of polyhydroxyalkanoate production capacity, composition and weight synthesized by Burkholderia cepacia JC-1 from various carbon sources. Heliyon 2022; 8:e09174. [PMID: 35368536 PMCID: PMC8971576 DOI: 10.1016/j.heliyon.2022.e09174] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/27/2021] [Accepted: 03/17/2022] [Indexed: 12/17/2022] Open
Abstract
Polyhydroxyalkanoates (PHA) are microbial polymers that have received widespread attention in recent decades as potential alternatives to some petrochemical-based plastics. However, widespread use of PHA is often impeded by its cost of production. Therefore, the search for and systematic investigation of versatile microbial PHA producers capable of using various carbon sources, even in the form of animal fats, for PHA biosynthesis is desirable. This study highlights the PHA production capacity, monomer composition and molecular weight synthesized by Burkholderia cepacia JC-1, a locally isolated strain from soil, from various carbon sources. In the category of simple sugars and plant oils, the use of glucose and palm oil at C:N ratio of 40 resulted in the highest accumulation of 52 wt% and 36 wt% poly(3-hydroxybutyrate) [P(3HB)] homopolymer and dry cell weight of 2.56 g/L and 3.17 g/L, respectively. Interestingly, B. cepacia JC-1 was able to directly utilize animal-derived lipid in the form of crude and extracted chicken fat, resulting in appreciable dry cell weight and PHA contents of up to 3.19 g/L and 47 wt% respectively, surpassing even that of palm oil in the group of triglycerides as substrates. The presence of antibiotics (streptomycin) in cultivation medium did not significantly affect cell growth and polymer production. The supply of sodium pentanoate as a co-substrate resulted in the incorporation of 3-hydroxyvalerate (3HV) monomer at fractions up to 37 mol%. The molecular weight of polymers produced from glucose, palm oil and chicken fat were in the range of 991–2118 kDa, higher than some reported studies involving native strains. The results from this study form an important basis for possible improvements in using B. cepacia JC-1 and crude chicken fats in solid form for PHA production in the future.
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Affiliation(s)
- Julian Hock-Chye Chin
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia
| | - Mohd Razip Samian
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia
| | - Yahaya M Normi
- Enzyme and Microbial Technology (EMTech) Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.,Department of Cell and Molecular Biology, Faculty of Biotechnology and Bimolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
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10
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Meng D, Miao C, Liu Y, Wang F, Chen L, Huang Z, Fan X, Gu P, Li Q. Metabolic engineering for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose and propionic acid in recombinant Escherichia coli. BIORESOURCE TECHNOLOGY 2022; 348:126786. [PMID: 35114368 DOI: 10.1016/j.biortech.2022.126786] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
In this study, novel polyhydroxyalkanoate (PHA)-associated genes (phaCp and phaABp) cloned from Propylenella binzhouense L72T were expressed in Escherichiacoli cells for PHA production, and the recombinant strains were used to analyze PHA yields with various substrates. The highest poly (3-hydroxybutyrate-co-3-hydroxy-valerate) (PHBV) yield (1.06 g/L) and cell dry weight (3.31 g/L) in E. coli DH5α/ΔptsG-CpABp were achieved by using glucose and propionicacid as substrates. Structural verification of PHBV produced by E. coli DH5α/ΔptsG-CpABp was performed to evaluate the characteristics of the polymers using Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. In addition, the X-ray diffraction results showed improved crystallinity of PHBV, and thermogravimetric analysis showed good thermal stability of 298 °C. The above findings indicated that the expression of phaCp and phaABp genes resulted in improved PHBV synthesis activity, and the polymer had better performance at higher processing temperatures.
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Affiliation(s)
- Dong Meng
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Changfeng Miao
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Yuling Liu
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Fang Wang
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Lu Chen
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Zhaosong Huang
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Xiangyu Fan
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Pengfei Gu
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Qiang Li
- School of Biological Science and Technology, University of Jinan, Jinan, PR China.
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11
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Aduhene AG, Cui H, Yang H, Liu C, Sui G, Liu C. Poly(3-hydroxypropionate): Biosynthesis Pathways and Malonyl-CoA Biosensor Material Properties. Front Bioeng Biotechnol 2021; 9:646995. [PMID: 33748091 PMCID: PMC7978226 DOI: 10.3389/fbioe.2021.646995] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/09/2021] [Indexed: 01/25/2023] Open
Abstract
Many single-use non-degradable plastics are a threat to life today, and several polyhydroxyalkanoates (PHAs) biopolymers have been developed in the bioplastic industry to place petrochemical-based plastics. One of such is the novel biomaterial poly(3-hydroxypropionate) [poly(3HP)] because of its biocompatibility, biodegradability, and high yield synthesis using engineered strains. To date, many bio-polymer-based functional composites have been developed to increase the value of raw microbial-biopolymers obtained from cheap sources. This review article broadly covers poly(3HP), a comprehensive summary of critical biosynthetic production pathways comparing the yields and titers achieved in different Microbial cell Factories. This article also provides extensive knowledge and highlights recent progress on biosensors' use to optimize poly(3HP) production, some bacteria host adopted for production, chemical and physical properties, life cycle assessment for poly(3HP) production using corn oil as carbon source, and some essential medical applications of poly(3HP).
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Affiliation(s)
- Albert Gyapong Aduhene
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Hongliang Cui
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Hongyi Yang
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Chengwei Liu
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Guangchao Sui
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Changli Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
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12
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Yu L, Zhang S, Xu Y, Mi X, Xing T, Li J, Zhang L, Gao F, Jiang Y. Acid resistance of E. coli O157:H7 and O26:H11 exposure to lactic acid revealed by transcriptomic analysis. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Tang S, Hicks ND, Cheng YS, Silva A, Fortune SM, Sacchettini JC. Structural and functional insight into the Mycobacterium tuberculosis protein PrpR reveals a novel type of transcription factor. Nucleic Acids Res 2019; 47:9934-9949. [PMID: 31504787 PMCID: PMC6765138 DOI: 10.1093/nar/gkz724] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/19/2019] [Accepted: 08/07/2019] [Indexed: 01/15/2023] Open
Abstract
The pathogenicity of Mycobacterium tuberculosis depends upon its ability to catabolize host cholesterol. Upregulation of the methylcitrate cycle (MCC) is required to assimilate and detoxify propionyl-CoA, a cholesterol degradation product. The transcription of key genes prpC and prpD in MCC is activated by MtPrpR, a member of a family of prokaryotic transcription factors whose structures and modes of action have not been clearly defined. We show that MtPrpR has a novel overall structure and directly binds to CoA or short-chain acyl-CoA derivatives to form a homotetramer that covers the binding cavity and locks CoA tightly inside the protein. The regulation of this process involves a [4Fe4S] cluster located close to the CoA-binding cavity on a neighboring chain. Mutations in the [4Fe4S] cluster binding residues rendered MtPrpR incapable of regulating MCC gene transcription. The structure of MtPrpR without the [4Fe4S] cluster-binding region shows a conformational change that prohibits CoA binding. The stability of this cluster means it is unlikely a redox sensor but may function by sensing ambient iron levels. These results provide mechanistic insights into this family of critical transcription factors who share similar structures and regulate gene transcription using a combination of acyl-CoAs and [4Fe4S] cluster.
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Affiliation(s)
- Su Tang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840, USA
| | - Nathan D Hicks
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Yu-Shan Cheng
- Department of Chemistry, Texas A&M University, College Station, TX 77840, USA
| | - Andres Silva
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840, USA
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - James C Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840, USA.,Department of Chemistry, Texas A&M University, College Station, TX 77840, USA
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14
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McLaughlin PT, Bhardwaj V, Feeley BE, Higgs PI. MrpC, a CRP/Fnr homolog, functions as a negative autoregulator during the
Myxococcus xanthus
multicellular developmental program. Mol Microbiol 2018; 109:245-261. [DOI: 10.1111/mmi.13982] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/05/2018] [Accepted: 05/05/2018] [Indexed: 02/06/2023]
Affiliation(s)
| | - Vidhi Bhardwaj
- Department of EcophysiologyMax Planck Institute for Terrestrial MicrobiologyMarburg Hesse Germany
| | - Brooke E. Feeley
- Department of Biological SciencesWayne State UniversityDetroit MI USA
| | - Penelope I. Higgs
- Department of Biological SciencesWayne State UniversityDetroit MI USA
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15
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Dolan SK, Wijaya A, Geddis SM, Spring DR, Silva-Rocha R, Welch M. Loving the poison: the methylcitrate cycle and bacterial pathogenesis. Microbiology (Reading) 2018; 164:251-259. [DOI: 10.1099/mic.0.000604] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
| | - Andre Wijaya
- Department of Biochemistry, University of Cambridge, UK
| | | | | | - Rafael Silva-Rocha
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, UK
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16
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Enzyme IIA Ntr Regulates Salmonella Invasion Via 1,2-Propanediol And Propionate Catabolism. Sci Rep 2017; 7:44827. [PMID: 28333132 PMCID: PMC5363084 DOI: 10.1038/srep44827] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/15/2017] [Indexed: 11/08/2022] Open
Abstract
Many Proteobacteria possess a nitrogen-metabolic phosphotransferase system (PTSNtr) consisting of EINtr, NPr, and EIIANtr (encoded by ptsP, ptsO, and ptsN, respectively). The PTSNtr plays diverse regulatory roles, but the substrate phosphorylated by EIIANtr and its primary functions have not yet been identified. To comprehensively understand the roles of PTSNtr in Salmonella Typhimurium, we compared the whole transcriptomes of wild-type and a ΔptsN mutant. Genome-wide RNA sequencing revealed that 3.5% of the annotated genes were up- or down-regulated by three-fold or more in the absence of EIIANtr. The ΔptsN mutant significantly down-regulated the expression of genes involved in vitamin B12 synthesis, 1,2-propanediol utilization, and propionate catabolism. Moreover, the invasiveness of the ΔptsN mutant increased about 5-fold when 1,2-propanediol or propionate was added, which was attributable to the increased stability of HilD, the transcriptional regulator of Salmonella pathogenicity island-1. Interestingly, an abundance of 1,2-propanediol or propionate promoted the production of EIIANtr, suggesting the possibility of a positive feedback loop between EIIANtr and two catabolic pathways. These results demonstrate that EIIANtr is a key factor for the utilization of 1,2-propanediol and propionate as carbon and energy sources, and thereby modulates the invasiveness of Salmonella via 1,2-propanediol or propionate catabolism.
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17
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Marschall L, Sagmeister P, Herwig C. Tunable recombinant protein expression in E. coli: promoter systems and genetic constraints. Appl Microbiol Biotechnol 2017; 101:501-512. [PMID: 27999902 PMCID: PMC5566544 DOI: 10.1007/s00253-016-8045-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/26/2016] [Accepted: 11/29/2016] [Indexed: 12/11/2022]
Abstract
Tuning of transcription is a promising strategy to overcome challenges associated with a non-suitable expression rate like outgrowth of segregants, inclusion body formation, metabolic burden and inefficient translocation. By adjusting the expression rate-even on line-to purposeful levels higher product titres and more cost-efficient production processes can be achieved by enabling culture long-term stability and constant product quality. Some tunable systems are registered for patents or already commercially available. Within this contribution, we discuss the induction mechanisms of various Escherichia coli inherent promoter systems with respect to their tunability and review studies using these systems for expression tuning. According to the current level of knowledge, some promoter systems were successfully used for expression tuning, and in some cases, analytical evidence on single-cell level is still pending. However, only a few studies using tunable strains apply a suitable process control strategy. So far, expression tuning has only gathered little attention, but we anticipate that expression tuning harbours great potential for enabling and optimizing the production of a broad spectrum of products in E. coli.
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Affiliation(s)
- Lukas Marschall
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Vienna, Austria
| | | | - Christoph Herwig
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Vienna, Austria.
- Christian Doppler Laboratory for Mechanistic and Physiological Methods for Improved Bioprocesses, Vienna University of Technology, Gumpendorferstrasse 1a/166-4, A-1060, Vienna, Austria.
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18
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Simonte FM, Dötsch A, Galego L, Arraiano C, Gescher J. Investigation on the anaerobic propionate degradation byEscherichia coliK12. Mol Microbiol 2016; 103:55-66. [DOI: 10.1111/mmi.13541] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Francesca M. Simonte
- Department of Applied Biology; Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT); Karlsruhe Germany
| | - Andreas Dötsch
- Department of Microbiology on Natural and Technical Interfaces; Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT); Eggenstein-Leopoldshafen Germany
| | - Lisete Galego
- Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa; Oeiras Portugal
| | - Cecilia Arraiano
- Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa; Oeiras Portugal
| | - Johannes Gescher
- Department of Applied Biology; Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT); Karlsruhe Germany
- Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT); Eggenstein-Leopoldshafen Germany
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19
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Tervo CJ, Reed JL. MapMaker and PathTracer for tracking carbon in genome-scale metabolic models. Biotechnol J 2016; 11:648-61. [PMID: 26771089 DOI: 10.1002/biot.201500267] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 11/11/2015] [Accepted: 01/07/2016] [Indexed: 11/09/2022]
Abstract
Constraint-based reconstruction and analysis (COBRA) modeling results can be difficult to interpret given the large numbers of reactions in genome-scale models. While paths in metabolic networks can be found, existing methods are not easily combined with constraint-based approaches. To address this limitation, two tools (MapMaker and PathTracer) were developed to find paths (including cycles) between metabolites, where each step transfers carbon from reactant to product. MapMaker predicts carbon transfer maps (CTMs) between metabolites using only information on molecular formulae and reaction stoichiometry, effectively determining which reactants and products share carbon atoms. MapMaker correctly assigned CTMs for over 97% of the 2,251 reactions in an Escherichia coli metabolic model (iJO1366). Using CTMs as inputs, PathTracer finds paths between two metabolites. PathTracer was applied to iJO1366 to investigate the importance of using CTMs and COBRA constraints when enumerating paths, to find active and high flux paths in flux balance analysis (FBA) solutions, to identify paths for putrescine utilization, and to elucidate a potential CO2 fixation pathway in E. coli. These results illustrate how MapMaker and PathTracer can be used in combination with constraint-based models to identify feasible, active, and high flux paths between metabolites.
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Affiliation(s)
- Christopher J Tervo
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jennifer L Reed
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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20
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Genetically encoded sensors enable real-time observation of metabolite production. Proc Natl Acad Sci U S A 2016; 113:2388-93. [PMID: 26858408 DOI: 10.1073/pnas.1600375113] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Engineering cells to produce valuable metabolic products is hindered by the slow and laborious methods available for evaluating product concentration. Consequently, many designs go unevaluated, and the dynamics of product formation over time go unobserved. In this work, we develop a framework for observing product formation in real time without the need for sample preparation or laborious analytical methods. We use genetically encoded biosensors derived from small-molecule responsive transcription factors to provide a fluorescent readout that is proportional to the intracellular concentration of a target metabolite. Combining an appropriate biosensor with cells designed to produce a metabolic product allows us to track product formation by observing fluorescence. With individual cells exhibiting fluorescent intensities proportional to the amount of metabolite they produce, high-throughput methods can be used to rank the quality of genetic variants or production conditions. We observe production of several renewable plastic precursors with fluorescent readouts and demonstrate that higher fluorescence is indeed an indicator of higher product titer. Using fluorescence as a guide, we identify process parameters that produce 3-hydroxypropionate at 4.2 g/L, 23-fold higher than previously reported. We also report, to our knowledge, the first engineered route from glucose to acrylate, a plastic precursor with global sales of $14 billion. Finally, we monitor the production of glucarate, a replacement for environmentally damaging detergents, and muconate, a renewable precursor to polyethylene terephthalate and nylon with combined markets of $51 billion, in real time, demonstrating that our method is applicable to a wide range of molecules.
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21
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Feng X, Xian M, Liu W, Xu C, Zhang H, Zhao G. Biosynthesis of poly(3-hydroxypropionate) from glycerol using engineered Klebsiella pneumoniae strain without vitamin B12. Bioengineered 2016; 6:77-81. [PMID: 25621933 DOI: 10.1080/21655979.2015.1011027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. Previous studies demonstrated that engineered Escherichia coli strains can produce P3HP with supplementation of expensive vitamin B12. The present study examined the production of P3HP from glycerol in the recombinant Klebsiella pneumoniae strain, which naturally synthesizes vitamin B12. The genes glycerol dehydratase and its reactivation factor (dhaB123, gdrA, and gdrB from K. pneumoniae), aldehyde dehydrogenase (aldH from E. coli) were cloned and expressed in K. pneumoniae to produce 3-hydroxypropionate (3HP), with 2 genes (dhaT and yqhD) for biosynthesis of 1,3-propanediol were deleted. To obtain P3HP production, propionyl-CoA synthetase (prpE from E. coli) and polyhydroxyalkanoate synthase (phaC from Ralstonia eutropha) were introduced. Under the appropriate aeration condition, the cell yield and P3HP content were 0.24 g/L and 12.7% (wt/wt [cell dry weight]) respectively along with 2.03 g/L 3HP after 48 h cultivation. Although the yield is relatively low, this study shows the feasibility of producing P3HP in K. pneumoniae from glycerol without vitamin B12 for the first time. The results also suggest that the aeration conditions should be optimized carefully for the efficient production of P3HP.
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Affiliation(s)
- Xinjun Feng
- a CAS Key Laboratory of Biobased Materials; Qingdao Institute of Bioenergy and Bioprocess Technology ; Chinese Academy of Sciences ; Qingdao , China
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22
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Primary Amine Oxidase of Escherichia coli Is a Metabolic Enzyme that Can Use a Human Leukocyte Molecule as a Substrate. PLoS One 2015; 10:e0142367. [PMID: 26556595 PMCID: PMC4640556 DOI: 10.1371/journal.pone.0142367] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/21/2015] [Indexed: 12/17/2022] Open
Abstract
Escherichia coli amine oxidase (ECAO), encoded by the tynA gene, catalyzes the oxidative deamination of aromatic amines into aldehydes through a well-established mechanism, but its exact biological role is unknown. We investigated the role of ECAO by screening environmental and human isolates for tynA and characterizing a tynA-deletion strain using microarray analysis and biochemical studies. The presence of tynA did not correlate with pathogenicity. In tynA+ Escherichia coli strains, ECAO enabled bacterial growth in phenylethylamine, and the resultant H2O2 was released into the growth medium. Some aminoglycoside antibiotics inhibited the enzymatic activity of ECAO, which could affect the growth of tynA+ bacteria. Our results suggest that tynA is a reserve gene used under stringent environmental conditions in which ECAO may, due to its production of H2O2, provide a growth advantage over other bacteria that are unable to manage high levels of this oxidant. In addition, ECAO, which resembles the human homolog hAOC3, is able to process an unknown substrate on human leukocytes.
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23
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Franchini AG, Ihssen J, Egli T. Effect of Global Regulators RpoS and Cyclic-AMP/CRP on the Catabolome and Transcriptome of Escherichia coli K12 during Carbon- and Energy-Limited Growth. PLoS One 2015. [PMID: 26204448 PMCID: PMC4512719 DOI: 10.1371/journal.pone.0133793] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
For heterotrophic microbes, limited availability of carbon and energy sources is one of the major nutritional factors restricting the rate of growth in most ecosystems. Physiological adaptation to this hunger state requires metabolic versatility which usually involves expression of a wide range of different catabolic pathways and of high-affinity carbon transporters; together, this allows for simultaneous utilization of mixtures of carbonaceous compounds at low concentrations. In Escherichia coli the stationary phase sigma factor RpoS and the signal molecule cAMP are the major players in the regulation of transcription under such conditions; however, their interaction is still not fully understood. Therefore, during growth of E. coli in carbon-limited chemostat culture at different dilution rates, the transcriptomes, expression of periplasmic proteins and catabolomes of strains lacking one of these global regulators, either rpoS or adenylate cyclase (cya), were compared to those of the wild-type strain. The inability to synthesize cAMP exerted a strong negative influence on the expression of alternative carbon source uptake and degradation systems. In contrast, absence of RpoS increased the transcription of genes belonging to high-affinity uptake systems and central metabolism, presumably due to reduced competition of σD with σS. Phenotypical analysis confirmed this observation: The ability to respire alternative carbon substrates and to express periplasmic high-affinity binding proteins was eliminated in cya and crp mutants, while these properties were not affected in the rpoS mutant. As expected, transcription of numerous stress defence genes was negatively affected by the rpoS knock-out mutation. Interestingly, several genes of the RpoS stress response regulon were also down-regulated in the cAMP-negative strain indicating a coordinated global regulation. The results demonstrate that cAMP is crucial for catabolic flexibility during slow, carbon-limited growth, whereas RpoS is primarily involved in the regulation of stress response systems necessary for the survival of this bacterium under hunger conditions.
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Affiliation(s)
- Alessandro G. Franchini
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
- * E-mail:
| | - Julian Ihssen
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
| | - Thomas Egli
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
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24
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Peng Q, Wang G, Liu G, Zhang J, Song F. Identification of metabolism pathways directly regulated by sigma(54) factor in Bacillus thuringiensis. Front Microbiol 2015; 6:407. [PMID: 26029175 PMCID: PMC4428206 DOI: 10.3389/fmicb.2015.00407] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 04/19/2015] [Indexed: 11/13/2022] Open
Abstract
Sigma(54) (σ(54)) regulates nitrogen and carbon utilization in bacteria. Promoters that are σ(54)-dependent are highly conserved and contain short sequences located at the -24 and -12 positions upstream of the transcription initiation site. σ(54) requires regulatory proteins known as bacterial enhancer-binding proteins (bEBPs) to activate gene transcription. We show that σ(54) regulates the capacity to grow on various nitrogen sources using a Bacillus thuringiensis HD73 mutant lacking the sigL gene encoding σ(54) (ΔsigL). A 2-fold-change cutoff and a false discovery rate cutoff of P < 0.05 were used to analyze the DNA microarray data, which revealed 255 genes that were downregulated and 121 that were upregulated in the ΔsigL mutant relative to the wild-type HD73 strain. The σ(54) regulon (stationary phase) was characterized by DNA microarray, bioinformatics, and functional assay; 16 operons containing 47 genes were identified whose promoter regions contain the conserved -12/-24 element and whose transcriptional activities were abolished or reduced in the ΔsigL mutant. Eight σ(54)-dependent transcriptional bEBPs were found in the Bt HD73 genome, and they regulated nine σ(54)-dependent promoters. The metabolic pathways activated by σ(54) in this process have yet to be identified in Bacillus thuringiensis; nonetheless, the present analysis of the σ(54) regulon provides a better understanding of the physiological roles of σ factors in bacteria.
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Affiliation(s)
- Qi Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China
| | - Guannan Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China
| | - Guiming Liu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences Beijing, China
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China
| | - Fuping Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China
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25
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Li YF, Yu Z. Construction and evaluation of a genetic construct for specific detection and measurement of propionate by whole-cell bacteria. Biotechnol Bioeng 2014; 112:280-7. [DOI: 10.1002/bit.25358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Yueh-Fen Li
- Environmental Science Graduate Program; The Ohio State University; Columbus Ohio 43210
| | - Zhongtang Yu
- Environmental Science Graduate Program; The Ohio State University; Columbus Ohio 43210
- Department of Animal Sciences; The Ohio State University; Columbus Ohio 43210
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26
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Yamamoto K, Watanabe H, Ishihama A. Expression levels of transcription factors in Escherichia coli: growth phase- and growth condition-dependent variation of 90 regulators from six families. Microbiology (Reading) 2014; 160:1903-1913. [DOI: 10.1099/mic.0.079889-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression pattern of the genome in Escherichia coli is controlled by regulating the utilization of a limited number of RNA polymerases between a total of 4600 genes on its genome. The distribution pattern of RNA polymerase on the genome changes after two steps of protein–protein interaction with seven sigma subunits and about 300 transcription factors (TFs). Based on a systematic search for the regulation target promoters recognized by each TF, we propose two novel concepts: each TF regulates a number of target promoters; and each promoter is regulated by many TFs. In parallel, attempts have been made to determine the intracellular concentrations of all TFs using two systems: quantitative immunoblot analysis using TF-specific antibodies; and reporter assay of TF promoter activities. The direct measurement of TF protein level has so far been published for a set of 60 regulators with known functions. This study describes the determination of growth phase-dependent expression levels of 90 TFs using the reporter assay system. The translational fusion vector was constructed from the TF promoter sequence including an N-terminal proximal TF segment and the reporter GFP. At the beginning of cell growth, high-level expression was observed only for a small number of TFs. In the exponential phase, approximately 80 % TFs are expressed, but the expressed TF species change upon transfer to the stationary phase. Significant changes in the pattern of TF expression were observed between aerobic and anaerobic conditions. The list of intracellular levels of TFs provides further understanding to the transcription regulation of the E. coli genome under various stressful conditions.
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Affiliation(s)
- Kaneyoshi Yamamoto
- Research Institute of Micro-Nano Technology, Hosei University, Koganei, Tokyo 185-8584, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
| | - Hiroki Watanabe
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
| | - Akira Ishihama
- Research Institute of Micro-Nano Technology, Hosei University, Koganei, Tokyo 185-8584, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 185-8584, Japan
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Parisutham V, Jung SK, Nam D, Lee SK. Transcriptome-driven synthetic re-modeling of Escherichia coli to enhance cellobiose utilization. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2012.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Wang H, Liu B, Wang Q, Wang L. Genome-wide analysis of the salmonella Fis regulon and its regulatory mechanism on pathogenicity islands. PLoS One 2013; 8:e64688. [PMID: 23717649 PMCID: PMC3662779 DOI: 10.1371/journal.pone.0064688] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/17/2013] [Indexed: 11/19/2022] Open
Abstract
Fis, one of the most important nucleoid-associated proteins, functions as a global regulator of transcription in bacteria that has been comprehensively studied in Escherichia coli K12. Fis also influences the virulence of Salmonella enterica and pathogenic E. coli by regulating their virulence genes, however, the relevant mechanism is unclear. In this report, using combined RNA-seq and chromatin immunoprecipitation (ChIP)-seq technologies, we first identified 1646 Fis-regulated genes and 885 Fis-binding targets in the S. enterica serovar Typhimurium, and found a Fis regulon different from that in E. coli. Fis has been reported to contribute to the invasion ability of S. enterica. By using cell infection assays, we found it also enhances the intracellular replication ability of S. enterica within macrophage cell, which is of central importance for the pathogenesis of infections. Salmonella pathogenicity islands (SPI)-1 and SPI-2 are crucial for the invasion and survival of S. enterica in host cells. Using mutation and overexpression experiments, real-time PCR analysis, and electrophoretic mobility shift assays, we demonstrated that Fis regulates 63 of the 94 Salmonella pathogenicity island (SPI)-1 and SPI-2 genes, by three regulatory modes: i) binds to SPI regulators in the gene body or in upstream regions; ii) binds to SPI genes directly to mediate transcriptional activation of themselves and downstream genes; iii) binds to gene encoding OmpR which affects SPI gene expression by controlling SPI regulators SsrA and HilD. Our results provide new insights into the impact of Fis on SPI genes and the pathogenicity of S. enterica.
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Affiliation(s)
- Hui Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, P. R. China
| | - Bin Liu
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, P. R. China
| | - Quan Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, P. R. China
| | - Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, P. R. China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, P. R. China
- * E-mail:
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Cardinale S, Arkin AP. Contextualizing context for synthetic biology--identifying causes of failure of synthetic biological systems. Biotechnol J 2012; 7:856-66. [PMID: 22649052 PMCID: PMC3440575 DOI: 10.1002/biot.201200085] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/12/2012] [Accepted: 05/04/2012] [Indexed: 12/19/2022]
Abstract
Despite the efforts that bioengineers have exerted in designing and constructing biological processes that function according to a predetermined set of rules, their operation remains fundamentally circumstantial. The contextual situation in which molecules and single-celled or multi-cellular organisms find themselves shapes the way they interact, respond to the environment and process external information. Since the birth of the field, synthetic biologists have had to grapple with contextual issues, particularly when the molecular and genetic devices inexplicably fail to function as designed when tested in vivo. In this review, we set out to identify and classify the sources of the unexpected divergences between design and actual function of synthetic systems and analyze possible methodologies aimed at controlling, if not preventing, unwanted contextual issues.
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Affiliation(s)
- Stefano Cardinale
- Physical Biosciences Division, LBNL, Department of Bioengineering, University of California, Berkeley, CA, USA
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Park JM, Vinuselvi P, Lee SK. The mechanism of sugar-mediated catabolite repression of the propionate catabolic genes in Escherichia coli. Gene 2012; 504:116-21. [PMID: 22579471 DOI: 10.1016/j.gene.2012.04.074] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/22/2012] [Accepted: 04/22/2012] [Indexed: 01/30/2023]
Abstract
Carbon catabolite repression (CCR) is a well-known phenomenon that involves the preferential utilization of glucose as a carbon source. Cyclic adenosine monophosphate (cAMP) and the cAMP receptor protein (CRP) mediate CCR. Recently, a second CCR hierarchy that leads to the preferential consumption of arabinose over xylose, mediated by arabinose-bound AraC, has been identified. In this study, we report yet another CCR hierarchy that causes the preferential utilization of sugars (arabinose, galactose, glucose, mannose, and xylose) over a short-chain fatty acid (propionate). Expression of the propionate catabolic (prpBCDE) genes is down-regulated in the presence of these sugars. Sugar-mediated repression of the propionate catabolic genes is independent of sugar-specific regulators such as AraC and dependent on global regulators of sugar transport such as the cAMP-CRP complex and the Phosphotransferase System (PTS). Inhibition of the prpBCDE promoter is encountered during rapid sugar uptake and metabolism. This unique regulatory crosstalk between sugar metabolism and fatty acid metabolism may help provide new insights into CRP-dependent catabolite repression acting in conjunction with non-carbohydrate metabolism.
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Affiliation(s)
- Jung Min Park
- School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea
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Choi WS, Kim M, Park S, Lee SK, Kim T. Patterning and transferring hydrogel-encapsulated bacterial cells for quantitative analysis of synthetically engineered genetic circuits. Biomaterials 2012; 33:624-33. [DOI: 10.1016/j.biomaterials.2011.09.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 09/26/2011] [Indexed: 01/24/2023]
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Tan JS, Ramanan RN, Ling TC, Mustafa S, Ariff AB. The role of lac operon and lac repressor in the induction using lactose for the expression of periplasmic human interferon-α2b by Escherichia coli. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0394-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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BglBrick vectors and datasheets: A synthetic biology platform for gene expression. J Biol Eng 2011; 5:12. [PMID: 21933410 PMCID: PMC3189095 DOI: 10.1186/1754-1611-5-12] [Citation(s) in RCA: 328] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 09/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As engineered biological systems become more complex, it is increasingly common to express multiple operons from different plasmids and inducible expression systems within a single host cell. Optimizing such systems often requires screening combinations of origins of replication, expression systems, and antibiotic markers. This procedure is hampered by a lack of quantitative data on how these components behave when more than one origin of replication or expression system are used simultaneously. Additionally, this process can be time consuming as it often requires the creation of new vectors or cloning into existing but disparate vectors. RESULTS Here, we report the development and characterization of a library of expression vectors compatible with the BglBrick standard (BBF RFC 21). We have designed and constructed 96 BglBrick-compatible plasmids with a combination of replication origins, antibiotic resistance genes, and inducible promoters. These plasmids were characterized over a range of inducer concentrations, in the presence of non-cognate inducer molecules, and with several growth media, and their characteristics were documented in a standard format datasheet. A three plasmid system was used to investigate the impact of multiple origins of replication on plasmid copy number. CONCLUSIONS The standardized collection of vectors presented here allows the user to rapidly construct and test the expression of genes with various combinations of promoter strength, inducible expression system, copy number, and antibiotic resistance. The quantitative datasheets created for these vectors will increase the predictability of gene expression, especially when multiple plasmids and inducers are utilized.
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Production in Escherichia coli of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with differing monomer compositions from unrelated carbon sources. Appl Environ Microbiol 2011; 77:4886-93. [PMID: 21652742 DOI: 10.1128/aem.00091-11] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The industrial production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has been hindered by high cost and a complex control strategy caused by the addition of propionate. In this study, based on analysis of the PHBV biosynthesis process, we developed a PHBV biosynthetic pathway from a single unrelated carbon source via threonine biosynthesis in Escherichia coli. To accomplish this, we (i) overexpressed threonine deaminase, which is the key factor for providing propionyl-coenzyme A (propionyl-CoA), from different host bacteria, (ii) removed the feedback inhibition of threonine by mutating and overexpressing the thrABC operon in E. coli, and (iii) knocked out the competitive pathways of catalytic conversion of propionyl-CoA to 3-hydroxyvaleryl-CoA. Finally, we constructed a series of strains and mutants which were able to produce the PHBV copolymer with differing monomer compositions in a modified M9 medium supplemented with 20 g/liter xylose. The largest 3-hydroxyvalerate fraction obtained in the copolymer was 17.5 mol%.
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Manso I, García JL, Galán B. Escherichia coli mhpR gene expression is regulated by catabolite repression mediated by the cAMP-CRP complex. MICROBIOLOGY-SGM 2010; 157:593-600. [PMID: 20966094 DOI: 10.1099/mic.0.043620-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The expression of the mhp genes involved in the degradation of the aromatic compound 3-(3-hydroxyphenyl)propionic acid (3HPP) in Escherichia coli is dependent on the MhpR transcriptional activator at the Pa promoter. This catabolic promoter is also subject to catabolic repression in the presence of glucose mediated by the cAMP-CRP complex. The Pr promoter drives the MhpR-independent expression of the regulatory gene. In vivo and in vitro experiments have shown that transcription from the Pr promoter is downregulated by the addition of glucose and this catabolic repression is also mediated by the cAMP-CRP complex. The activation role of the cAMP-CRP regulatory system was further investigated by DNase I footprinting assays, which showed that the cAMP-CRP complex binds to the Pr promoter sequence, protecting a region centred at position -40.5, which allowed the classification of Pr as a class II CRP-dependent promoter. Open complex formation at the Pr promoter is observed only when RNA polymerase and cAMP-CRP are present. Finally, by in vitro transcription assays we have demonstrated the absolute requirement of the cAMP-CRP complex for the activation of the Pr promoter.
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Affiliation(s)
- I Manso
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - J L García
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - B Galán
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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Synthetic protein scaffolds provide modular control over metabolic flux. Nat Biotechnol 2009; 27:753-9. [PMID: 19648908 DOI: 10.1038/nbt.1557] [Citation(s) in RCA: 902] [Impact Index Per Article: 60.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 07/07/2009] [Indexed: 11/08/2022]
Abstract
Engineered metabolic pathways constructed from enzymes heterologous to the production host often suffer from flux imbalances, as they typically lack the regulatory mechanisms characteristic of natural metabolism. In an attempt to increase the effective concentration of each component of a pathway of interest, we built synthetic protein scaffolds that spatially recruit metabolic enzymes in a designable manner. Scaffolds bearing interaction domains from metazoan signaling proteins specifically accrue pathway enzymes tagged with their cognate peptide ligands. The natural modularity of these domains enabled us to optimize the stoichiometry of three mevalonate biosynthetic enzymes recruited to a synthetic complex and thereby achieve 77-fold improvement in product titer with low enzyme expression and reduced metabolic load. One of the same scaffolds was used to triple the yield of glucaric acid, despite high titers (0.5 g/l) without the synthetic complex. These strategies should prove generalizeable to other metabolic pathways and programmable for fine-tuning pathway flux.
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Participation of regulator AscG of the beta-glucoside utilization operon in regulation of the propionate catabolism operon. J Bacteriol 2009; 191:6136-44. [PMID: 19633077 DOI: 10.1128/jb.00663-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The asc operon of Escherichia coli is one of the cryptic genetic systems for beta-D-galactoside utilization as a carbon source. The ascFB genes for beta-D-galactoside transport and catabolism are repressed by the AscG regulator. After genomic SELEX screening, AscG was found to recognize and bind the consensus palindromic sequence TGAAACC-GGTTTCA. AscG binding was detected at two sites upstream of the ascFB promoter and at three sites upstream of the prpBC operon for propionate catabolism. In an ascG-disrupted mutant, transcription of ascFB was enhanced, in agreement with the repressor model of AscG. This repression was indicated to be due to interference of binding of cyclic AMP-CRP to the CRP box, which overlaps with the AscG-binding site 1, as well as binding of RNA polymerase to the promoter. Under conditions of steady-state E. coli growth in a rich medium, the intracellular level of AscG stayed constant at a level supposedly leading to tight repression of the ascFB operon. The level of prpR, encoding the activator of prpBCDE, was also increased in the absence of AscG, indicating the involvement of AscG in repression of prpR. Taken together, these data suggest a metabolic link through interplay between the asc and prp operons.
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Ham TS, Lee SK, Keasling JD, Arkin AP. Design and construction of a double inversion recombination switch for heritable sequential genetic memory. PLoS One 2008; 3:e2815. [PMID: 18665232 PMCID: PMC2481393 DOI: 10.1371/journal.pone.0002815] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 06/30/2008] [Indexed: 11/18/2022] Open
Abstract
Background Inversion recombination elements present unique opportunities for computing and information encoding in biological systems. They provide distinct binary states that are encoded into the DNA sequence itself, allowing us to overcome limitations posed by other biological memory or logic gate systems. Further, it is in theory possible to create complex sequential logics by careful positioning of recombinase recognition sites in the sequence. Methodology/Principal Findings In this work, we describe the design and synthesis of an inversion switch using the fim and hin inversion recombination systems to create a heritable sequential memory switch. We have integrated the two inversion systems in an overlapping manner, creating a switch that can have multiple states. The switch is capable of transitioning from state to state in a manner analogous to a finite state machine, while encoding the state information into DNA. This switch does not require protein expression to maintain its state, and “remembers” its state even upon cell death. We were able to demonstrate transition into three out of the five possible states showing the feasibility of such a switch. Conclusions/Significance We demonstrate that a heritable memory system that encodes its state into DNA is possible, and that inversion recombination system could be a starting point for more complex memory circuits. Although the circuit did not fully behave as expected, we showed that a multi-state, temporal memory is achievable.
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Affiliation(s)
- Timothy S Ham
- Department of Bioengineering, University of California, Berkeley, California, United States of America
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Lee SK, Keasling JD. Heterologous protein production in Escherichia coli using the propionate-inducible pPro system by conventional and auto-induction methods. Protein Expr Purif 2008; 61:197-203. [PMID: 18639640 DOI: 10.1016/j.pep.2008.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 10/21/2022]
Abstract
We examined expression of two plant genes encoding coclaurine N-methyltransferase (CMT) and norcoclaurine synthase (NCS) in Escherichia coli from the Salmonella entericaprpBCDE promoter (P(prpB)) and compared it to that from the strongest IPTG-inducible promoter, P(T7). In contrast to our previous study showing slightly higher production of green fluorescent protein (GFP) from the pPro system compared to that from the T7 system, production of two plant proteins CMT and NCS from P(prpB) was 2- to 4-fold higher than that from P(T7). Unlike P(T7), expression from P(prpB) did not reduce cell growth even when highly induced, indicating that this propionate-inducible system is more efficient for overproduction of proteins that result in growth inhibition. In an auto-induction experiment, which does not require monitoring the culture or adding inducer during cell growth, the pPro system exhibited much higher protein production than the T7 system. These results strongly indicate that the pPro system is well-suited for overproduction of recombinant proteins.
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Affiliation(s)
- Sung Kuk Lee
- Department of Chemical Engineering, University of California, Berkeley, CA 94720, USA.
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40
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Akyol I, Comlekcioglu U, Karakas A, Serdaroglu K, Ekinci MS, Ozkose E. Regulation of the acid induciblercfB promoter inLactococcus lactis subsp.lactis. ANN MICROBIOL 2008. [DOI: 10.1007/bf03175328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Abstract
The richness and versatility of biological systems make them ideally suited to solve some of the world's most significant challenges, such as converting cheap, renewable resources into energy-rich molecules; producing high-quality, inexpensive drugs to fight disease; and remediating polluted sites. Over the years, significant strides have been made in engineering microorganisms to produce fuels, bulk chemicals, and valuable drugs from inexpensive starting materials; to detect and degrade nerve agents as well as less toxic organic pollutants; and to accumulate metals and reduce radionuclides. The components needed to engineer the chemistry inside a microbial cell are significantly different from those commonly used to overproduce pharmaceutical proteins. Synthetic biology has had and will continue to have a significant impact on the development of these components to engineer cellular metabolism and microbial chassis to host the chemistry. The ready availability of more well-characterized gene expression components and hosts for chemical synthesis, standards for the connection of these components to make larger functioning devices, computer-aided design software, and debugging tools for biological designs will decrease both the time and the support needed to construct these designs. Some of the most important tools for engineering bacterial metabolism and their use for production of the antimalarial drug artemisinin are reviewed.
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Affiliation(s)
- Jay D. Keasling
- Departments of Chemical Engineering and Bioengineering, University of California, Berkeley, Berkeley, California 94720, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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Makart S, Heinemann M, Panke S. Characterization of the AlkS/P(alkB)-expression system as an efficient tool for the production of recombinant proteins in Escherichia coli fed-batch fermentations. Biotechnol Bioeng 2007; 96:326-36. [PMID: 16865736 DOI: 10.1002/bit.21117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The availability of suitable, well-characterized, and robust expression systems remains an essential requirement for successful metabolic engineering and recombinant protein production. We investigated the suitability of the Pseudomonas putida GPo1-derived AlkS/P(alkB) expression system in strictly aqueous cultures. By applying the apolar inducer dicyclopropylketone (DCPK) to express green fluorescent protein (GFP) from this system in Escherichia coli and analyzing the resulting cultures on single-cell level by flow cytometry, we found that this expression system gives rise to a homogeneous population of cells, even though the overall system is expected to have a positive feed-back element in the expression of the regulatory gene alkS. Overexpressing E. coli's serine hydroxymethyltransferase gene glyA, we showed that the system was already fully turned on at inducer concentrations as low as 0.005% (v/v). This allows efficient mass production of recombinant enzymes even though DCPK concentrations decreased from 0.05% to 0.01% over the course of a fully aerated cultivation in aqueous medium. Therefore, we elaborated the optimum induction procedure for production of the biocatalytically promising serine hydroxymethyltransferase and found volumetric and specific productivity to increase with specific growth rate in glucose-limited fed-batch cultures. Acetate excretion as a result of recombinant protein production could be avoided in an optimized fermentation protocol by switching earlier to a linear feed. This protocol resulted in a production of a final cell dry weight (CDW) concentration of 52 g/L, producing recombinant GlyA with a maximum specific activity of 6.3 U/mg total protein.
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Affiliation(s)
- Stefan Makart
- Bioprocess Laboratory, Institute of Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
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Shiba Y, Paradise EM, Kirby J, Ro DK, Keasling JD. Engineering of the pyruvate dehydrogenase bypass in Saccharomyces cerevisiae for high-level production of isoprenoids. Metab Eng 2006; 9:160-8. [PMID: 17196416 DOI: 10.1016/j.ymben.2006.10.005] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2006] [Revised: 10/05/2006] [Accepted: 10/09/2006] [Indexed: 11/28/2022]
Abstract
Amorphadiene, a sesquiterpene precursor to the anti-malarial drug artemisinin, is synthesized by the cyclization of farnesyl pyrophosphate (FPP). Saccharomyces cerevisiae produces FPP through the mevalonate pathway using acetyl-CoA as a starting compound. In order to enhance the supply of acetyl-CoA to the mevalonate pathway and achieve high-level production of amorphadiene, we engineered the pyruvate dehydrogenase bypass in S. cerevisiae. Overproduction of acetaldehyde dehydrogenase and introduction of a Salmonella enterica acetyl-CoA synthetase variant increased the carbon flux into the mevalonate pathway resulting in increased amorphadiene production. This work will be generally applicable to the production of a broad range of isoprenoids in yeast.
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Affiliation(s)
- Yoichiro Shiba
- Berkeley Center for Synthetic Biology, Department of Chemical Engineering, University of California, 717 Potter Street, Building 977, Mail code 3224, Berkeley, CA 94720-3224, USA
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Franchini AG, Egli T. Global gene expression in Escherichia coli K-12 during short-term and long-term adaptation to glucose-limited continuous culture conditions. MICROBIOLOGY-SGM 2006; 152:2111-2127. [PMID: 16804185 DOI: 10.1099/mic.0.28939-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Microarray technology was used to study the cellular events that take place at the transcription level during short-term (physiological) and long-term (genetic) adaptation of the faecal indicator bacterium Escherichia coli K-12 to slow growth under limited nutrient supply. Short-term and long-term adaptation were assessed by comparing the mRNA levels isolated after 40 or 500 h of glucose-limited continuous culture at a dilution rate of 0.3 h(-1) with those from batch culture with glucose excess. A large number of genes encoding periplasmic binding proteins were upregulated, indicating that the cells are prepared for high-affinity uptake of all types of carbon sources during glucose-limited growth in continuous culture. All the genes belonging to the maltose (mal/lamB) and galactose (mgl/gal) operons were upregulated. A similar transcription pattern was observed for long-term cultures except that the expression factors were lower than in the short-term adaptation. The patterns of upregulation were confirmed by real-time RT-PCR. A switch from a fully operational citric acid cycle to the PEP-glyoxylate cycle was clearly observed in cells grown in glucose-limited continuous culture when compared to batch-grown cells and this was confirmed by transcriptome analysis. This transcriptome analysis confirms and extends the observations from previous proteome and catabolome studies in the authors' laboratory.
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Affiliation(s)
- Alessandro G Franchini
- Swiss Federal Institute for Aquatic Science and Technology, PO Box 611, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
| | - Thomas Egli
- Swiss Federal Institute for Aquatic Science and Technology, PO Box 611, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
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Lee SK, Keasling JD. A Salmonella-based, propionate-inducible, expression system for Salmonella enterica. Gene 2006; 377:6-11. [PMID: 16616438 DOI: 10.1016/j.gene.2006.02.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 02/17/2006] [Accepted: 02/22/2006] [Indexed: 11/28/2022]
Abstract
The expression and regulatory properties of a propionate-regulated overexpression system (Salmonella enterica prpBCDE promoter (P(prpB)) and positive regulator (prpR)) were evaluated in wild-type S. enterica serovar Typhimurium TR6583 and prpB(-) or prpD(-) versions of this strain and compared with the arabinose-regulated T7 expression system. The wild-type strain showed low expression in the absence of propionate and high expression in the presence of propionate under all growth conditions. In 96-well plates and culture tubes, the wild-type strain exhibited a long delay before full induction; the time delay was significantly shorter in shake flasks. The prpD(-) strain exhibited low expression in the presence of glucose, highly regulatable expression over a wide range of propionate concentrations, and, in contrast to the wild-type strain, fast induction to full expression under all growth conditions. In contrast, the prpB(-) strain showed very high background expression in both culture tubes and shake flasks.
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Affiliation(s)
- Sung Kuk Lee
- Department of Chemical Engineering, University of California, Berkeley, 94720, USA
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Lee SK, Keasling JD. Propionate-regulated high-yield protein production inEscherichia coli. Biotechnol Bioeng 2006; 93:912-8. [PMID: 16333863 DOI: 10.1002/bit.20784] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A new expression system containing the Salmonella enterica prpBCDE promoter (P(prpB)) responsible for expression of the propionate catabolic genes (prp BCDE) and prpR encoding the positive regulator of this promoter has been developed and tested. The main features of the expression system compared to those based on the bacteriophage T7 promoter are low background expression and high induced expression in Escherichia coli strains BL21, BL21(DE3), MG1655, and W3110. In addition, propionate is an inexpensive, simple-to-use, nontoxic inducer that is attractive for large-scale protein production. Hence, this new system is highly complementary to the widely used T7 promoter-driven expression systems.
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Affiliation(s)
- Sung Kuk Lee
- Department of Chemical Engineering and Bioengineering, University of California, Synthetic Biology Department, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Lee SK, Keasling JD. Effect of Glucose or Glycerol as the Sole Carbon Source on Gene Expression from theSalmonella prpBCDEPromoter inEscherichia coli. Biotechnol Prog 2006. [DOI: 10.1002/bp060193f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
A series of new expression vectors (pPro) have been constructed for the regulated expression of genes in Escherichia coli. The pPro vectors contain the prpBCDE promoter (P(prpB)) responsible for expression of the propionate catabolic genes (prpBCDE) and prpR encoding the positive regulator of this promoter. The efficiency and regulatory properties of the prpR-P(prpB) system were measured by placing the gene encoding the green fluorescent protein (gfp) under the control of the inducible P(prpB) of E. coli. This system provides homogenous expression in individual cells, highly regulatable expression over a wide range of propionate concentrations, and strong expression (maximal 1,500-fold induction) at high propionate concentrations. Since the prpBCDE promoter has CAP-dependent activation, the prpR-P(prpB) system exhibited negligible basal expression by addition of glucose to the medium.
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Affiliation(s)
- Sung Kuk Lee
- Department of Chemical Engineering, University of California, Berkeley, CA 94720, USA
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