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Kelly S, Tham JL, McKeever K, Dillon E, O'Connell D, Scholz D, Simpson JC, O'Connor K, Narancic T, Cagney G. Comprehensive Proteomics Analysis of Polyhydroxyalkanoate (PHA) Biology in Pseudomonas putida KT2440: The Outer Membrane Lipoprotein OprL is a Newly Identified Phasin. Mol Cell Proteomics 2024; 23:100765. [PMID: 38608840 PMCID: PMC11103573 DOI: 10.1016/j.mcpro.2024.100765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/01/2024] [Accepted: 03/23/2024] [Indexed: 04/14/2024] Open
Abstract
Pseudomonas putida KT2440 is an important bioplastic-producing industrial microorganism capable of synthesizing the polymeric carbon-rich storage material, polyhydroxyalkanoate (PHA). PHA is sequestered in discrete PHA granules, or carbonosomes, and accumulates under conditions of stress, for example, low levels of available nitrogen. The pha locus responsible for PHA metabolism encodes both anabolic and catabolic enzymes, a transcription factor, and carbonosome-localized proteins termed phasins. The functions of phasins are incompletely understood but genetic disruption of their function causes PHA-related phenotypes. To improve our understanding of these proteins, we investigated the PHA pathways of P.putida KT2440 using three types of experiments. First, we profiled cells grown in nitrogen-limited and nitrogen-excess media using global expression proteomics, identifying sets of proteins found to coordinately increase or decrease within clustered pathways. Next, we analyzed the protein composition of isolated carbonosomes, identifying two new putative components. We carried out physical interaction screens focused on PHA-related proteins, generating a protein-protein network comprising 434 connected proteins. Finally, we confirmed that the outer membrane protein OprL (the Pal component of the Pal-Tol system) localizes to the carbonosome and shows a PHA-related phenotype and therefore is a novel phasin. The combined datasets represent a valuable overview of the protein components of the PHA system in P.putida highlighting the complex nature of regulatory interactions responsive to nutrient stress.
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Affiliation(s)
- Siobhan Kelly
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Jia-Lynn Tham
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Kate McKeever
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Eugene Dillon
- UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - David O'Connell
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Dimitri Scholz
- UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Jeremy C Simpson
- UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; UCD Earth Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Kevin O'Connor
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland; UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
| | - Tanja Narancic
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland.
| | - Gerard Cagney
- BiOrbic - Bioeconomy Research Centre, University College Dublin, Belfield, Dublin, Ireland; UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland; School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland.
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2
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Mitra R, Xu T, Chen GQ, Xiang H, Han J. An updated overview on the regulatory circuits of polyhydroxyalkanoates synthesis. Microb Biotechnol 2021; 15:1446-1470. [PMID: 34473895 PMCID: PMC9049629 DOI: 10.1111/1751-7915.13915] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022] Open
Abstract
Polyhydroxyalkanoates (PHA) are a promising and sustainable alternative to the petroleum‐based synthetic plastics. Regulation of PHA synthesis is receiving considerable importance as engineering the regulatory factors might help developing strains with improved PHA‐producing abilities. PHA synthesis is dedicatedly regulated by a number of regulatory networks. They tightly control the PHA content, granule size and their distribution in cells. Most PHA‐accumulating microorganisms have multiple regulatory networks that impart a combined effect on PHA metabolism. Among them, several factors ranging from global to specific regulators, have been identified and characterized till now. This review is an attempt to categorically summarize the diverse regulatory circuits that operate in some important PHA‐producing microorganisms. However, in several organisms, the detailed mechanisms involved in the regulation of PHA synthesis is not well‐explored and hence further research is needed. The information presented in this review might help researcher to identify the prevailing research gaps in PHA regulation.
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Affiliation(s)
- Ruchira Mitra
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,International College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tong Xu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Han
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
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4
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Tobramycin Adaptation Enhances Policing of Social Cheaters in Pseudomonas aeruginosa. Appl Environ Microbiol 2021; 87:e0002921. [PMID: 33837019 DOI: 10.1128/aem.00029-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Pseudomonas aeruginosa LasR-LasI (LasR-I) quorum sensing system regulates secreted proteases that can be exploited by cheaters, such as quorum sensing receptor-defective (lasR) mutants. lasR mutants emerge in populations growing on casein as a sole source of carbon and energy. These mutants are exploitative cheaters because they avoid the substantial cost of engaging in quorum sensing. Previous studies showed that quorum sensing increases resistance to some antibiotics, such as tobramycin. Here, we show that tobramycin suppressed the emergence of lasR mutants in casein-passaged populations. Several mutations accumulated in those populations, indicating evidence of antibiotic adaptation. We found that mutations in one gene, ptsP, increased antibiotic resistance and also pleiotropically increased production of a quorum sensing-controlled phenazine, pyocyanin. When passaged on casein, ptsP mutants suppressed cheaters in a manner that was tobramycin independent. We found that the mechanism of cheater suppression in ptsP mutants relied on pyocyanin, which acts as a policing toxin by selectively blocking growth of cheaters. Thus, tobramycin suppresses lasR mutants through two mechanisms: first, through direct effects on cheaters and, second, by selecting mutations in ptsP that suppressed cheating in a tobramycin-independent manner. This work demonstrates how adaptive mutations can alter the dynamics of cooperator-cheater relationships, which might be important for populations adapting to antibiotics during interspecies competition or infections. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa is a model for understanding quorum sensing, a type of cell-cell signaling important for cooperation. Quorum sensing controls production of cooperative goods, such as exoenzymes, which are vulnerable to cheating by quorum sensing-defective mutants. Because uncontrolled cheating can ultimately cause a population to collapse, much focus has been on understanding how P. aeruginosa can control cheaters. We show that an antibiotic, tobramycin, can suppress cheaters in cooperating P. aeruginosa populations. Tobramycin suppresses cheaters directly because the cheaters are more susceptible to tobramycin than cooperators. Tobramycin also selects for mutations in a gene, ptsP, that suppresses cheaters independent of tobramycin through pleiotropic regulation of a policing toxin, pyocyanin. This work supports the idea that adaptation to antibiotics can have unexpected effects on the evolution of quorum sensing and has implications for understanding how cooperation evolves in dynamic bacterial communities.
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Müller-Santos M, Koskimäki JJ, Alves LPS, de Souza EM, Jendrossek D, Pirttilä AM. The protective role of PHB and its degradation products against stress situations in bacteria. FEMS Microbiol Rev 2021; 45:fuaa058. [PMID: 33118006 DOI: 10.1093/femsre/fuaa058] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/26/2020] [Indexed: 12/15/2022] Open
Abstract
Many bacteria produce storage biopolymers that are mobilized under conditions of metabolic adaptation, for example, low nutrient availability and cellular stress. Polyhydroxyalkanoates are often found as carbon storage in Bacteria or Archaea, and of these polyhydroxybutyrate (PHB) is the most frequently occurring PHA type. Bacteria usually produce PHB upon availability of a carbon source and limitation of another essential nutrient. Therefore, it is widely believed that the function of PHB is to serve as a mobilizable carbon repository when bacteria face carbon limitation, supporting their survival. However, recent findings indicate that bacteria switch from PHB synthesis to mobilization under stress conditions such as thermal and oxidative shock. The mobilization products, 3-hydroxybutyrate and its oligomers, show a protective effect against protein aggregation and cellular damage caused by reactive oxygen species and heat shock. Thus, bacteria should have an environmental monitoring mechanism directly connected to the regulation of the PHB metabolism. Here, we review the current knowledge on PHB physiology together with a summary of recent findings on novel functions of PHB in stress resistance. Potential applications of these new functions are also presented.
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Affiliation(s)
- Marcelo Müller-Santos
- Department of Biochemistry and Molecular Biology, Federal University of Paraná - UFPR, Setor de Ciências Biológicas, Centro Politécnico, Jardim da Américas, CEP: 81531-990, Caixa Postal: 190-46, Curitiba, Paraná, Brazil
| | - Janne J Koskimäki
- Ecology and Genetics Research Unit, University of Oulu, Pentti Kaiteran katu 1, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Luis Paulo Silveira Alves
- Department of Biochemistry and Molecular Biology, Federal University of Paraná - UFPR, Setor de Ciências Biológicas, Centro Politécnico, Jardim da Américas, CEP: 81531-990, Caixa Postal: 190-46, Curitiba, Paraná, Brazil
| | - Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, Federal University of Paraná - UFPR, Setor de Ciências Biológicas, Centro Politécnico, Jardim da Américas, CEP: 81531-990, Caixa Postal: 190-46, Curitiba, Paraná, Brazil
| | - Dieter Jendrossek
- Institute of Microbiology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
| | - Anna Maria Pirttilä
- Ecology and Genetics Research Unit, University of Oulu, Pentti Kaiteran katu 1, P.O. Box 3000, FI-90014 Oulu, Finland
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6
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The role of transport proteins in the production of microbial glycolipid biosurfactants. Appl Microbiol Biotechnol 2021; 105:1779-1793. [PMID: 33576882 DOI: 10.1007/s00253-021-11156-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/20/2023]
Abstract
Several microorganisms are currently being used as production platform for glycolipid biosurfactants, providing a greener alternative to chemical biosurfactants. One of the reasons why these processes are commercially competitive is the fact that microbial producers can efficiently export their product to the extracellular environment, reaching high product titers. Glycolipid biosynthetic genes are often found in a dedicated cluster, amidst which genes encoding a dedicated transporter committed to shuttle the glycolipid to the extracellular environment are often found, as is the case for many other secondary metabolites. Knowing this, one can rely on gene clustering features to screen for novel putative transporters, as described and performed in this review. The above strategy proves to be very powerful to identify glycolipid transporters in fungi but is less valid for bacterial systems. Indeed, the genetics of these export systems are currently largely unknown, but some hints are given. Apart from the direct export of the glycolipid, several other transport systems have an indirect effect on glycolipid production. Specific importers dictate which hydrophilic and hydrophobic substrates can be used for production and influence the final yields. In eukaryotes, cellular compartmentalization allows the assembly of glycolipid building blocks in a highly specialized and efficient way. Yet, this requires controlled transport across intracellular membranes. Next to the direct export of glycolipids, the current state of the art regarding this indirect involvement of transporter systems in microbial glycolipid synthesis is summarized in this review. KEY POINTS: • Transporters are directly and indirectly involved in microbial glycolipid synthesis. • Yeast glycolipid transporters are found in their biosynthetic gene cluster. • Hydrophilic and hydrophobic substrate uptake influence microbial glycolipid synthesis.
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Mezzina MP, Manoli MT, Prieto MA, Nikel PI. Engineering Native and Synthetic Pathways in Pseudomonas putida for the Production of Tailored Polyhydroxyalkanoates. Biotechnol J 2020; 16:e2000165. [PMID: 33085217 DOI: 10.1002/biot.202000165] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/16/2020] [Indexed: 12/16/2022]
Abstract
Growing environmental concern sparks renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in the central metabolism of producer bacteria, as they act as dynamic reservoirs of carbon and reducing equivalents. PHAs continue to attract industrial attention as a starting point toward renewable, biodegradable, biocompatible, and versatile thermoplastic and elastomeric materials. Pseudomonas species have been known for long as efficient biopolymer producers, especially for medium-chain-length PHAs. The surge of synthetic biology and metabolic engineering approaches in recent years offers the possibility of exploiting the untapped potential of Pseudomonas cell factories for the production of tailored PHAs. In this article, an overview of the metabolic and regulatory circuits that rule PHA accumulation in Pseudomonas putida is provided, and approaches leading to the biosynthesis of novel polymers (e.g., PHAs including nonbiological chemical elements in their structures) are discussed. The potential of novel PHAs to disrupt existing and future market segments is closer to realization than ever before. The review is concluded by pinpointing challenges that currently hinder the wide adoption of bio-based PHAs, and strategies toward programmable polymer biosynthesis from alternative substrates in engineered P. putida strains are proposed.
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Affiliation(s)
- Mariela P Mezzina
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark
| | - María Tsampika Manoli
- Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas «Margarita Salas» (CIB-CSIC), Polymer Biotechnology Group, Madrid, 28040, Spain.,Spanish National Research Council (SusPlast-CSIC), Interdisciplinary Platform for Sustainable Plastics Toward a Circular Economy, Madrid, 28040, Spain
| | - M Auxiliadora Prieto
- Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas «Margarita Salas» (CIB-CSIC), Polymer Biotechnology Group, Madrid, 28040, Spain.,Spanish National Research Council (SusPlast-CSIC), Interdisciplinary Platform for Sustainable Plastics Toward a Circular Economy, Madrid, 28040, Spain
| | - Pablo I Nikel
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark
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8
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Wang S, Cui J, Bilal M, Hu H, Wang W, Zhang X. Pseudomonas spp. as cell factories (MCFs) for value-added products: from rational design to industrial applications. Crit Rev Biotechnol 2020; 40:1232-1249. [PMID: 32907412 DOI: 10.1080/07388551.2020.1809990] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In recent years, there has been increasing interest in microbial biotechnology for the production of value-added compounds from renewable resources. Pseudomonas species have been proposed as a suitable workhorse for high-value secondary metabolite production because of their unique characteristics for fast growth on sustainable carbon sources, a clear inherited background, versatile intrinsic metabolism with diverse enzymatic capacities, and their robustness in an extreme environment. It has also been demonstrated that metabolically engineered Pseudomonas strains can produce several industrially valuable aromatic chemicals and natural products such as phenazines, polyhydroxyalkanoates, rhamnolipids, and insecticidal proteins from renewable feedstocks with remarkably high yields suitable for commercial application. In this review, we summarize cell factory construction in Pseudomonas for the biosynthesis of native and non-native bioactive compounds in P. putida, P. chlororaphis, P. aeruginosa, as well as pharmaceutical proteins production by P. fluorescens. Additionally, some novel strategies together with metabolic engineering strategies in order to improve the biosynthetic abilities of Pseudomonas as an ideal chassis are discussed. Finally, we proposed emerging opportunities, challenges, and essential strategies to enable the successful development of Pseudomonas as versatile microbial cell factories for the bioproduction of diverse bioactive compounds.
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Affiliation(s)
- Songwei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jiajia Cui
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, China
| | - Hongbo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Velázquez-Sánchez C, Espín G, Peña C, Segura D. The Modification of Regulatory Circuits Involved in the Control of Polyhydroxyalkanoates Metabolism to Improve Their Production. Front Bioeng Biotechnol 2020; 8:386. [PMID: 32426348 PMCID: PMC7204398 DOI: 10.3389/fbioe.2020.00386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Poly-(3-hydroxyalkanoates) (PHAs) are bacterial carbon and energy storage compounds. These polymers are synthesized under conditions of nutritional imbalance, where a nutrient is growth-limiting while there is still enough carbon source in the medium. On the other side, the accumulated polymer is mobilized under conditions of nutrient accessibility or by limitation of the carbon source. Thus, it is well known that the accumulation of PHAs is affected by the availability of nutritional resources and this knowledge has been used to establish culture conditions favoring high productivities. In addition to this effect of the metabolic status on PHAs accumulation, several genetic regulatory networks have been shown to drive PHAs metabolism, so the expression of the PHAs genes is under the influence of global or specific regulators. These regulators are thought to coordinate PHAs synthesis and mobilization with the rest of bacterial physiology. While the metabolic and biochemical knowledge related to the biosynthesis of these polymers has led to the development of processes in bioreactors for high-level production and also to the establishment of strategies for metabolic engineering for the synthesis of modified biopolymers, the use of knowledge related to the regulatory circuits controlling PHAs metabolism for strain improvement is scarce. A better understanding of the genetic control systems involved could serve as the foundation for new strategies for strain modification in order to increase PHAs production or to adjust the chemical structure of these biopolymers. In this review, the regulatory systems involved in the control of PHAs metabolism are examined, with emphasis on those acting at the level of expression of the enzymes involved and their potential modification for strain improvement, both for higher titers, or manipulation of polymer properties. The case of the PHAs producer Azotobacter vinelandii is taken as an example of the complexity and variety of systems controlling the accumulation of these interesting polymers in response to diverse situations, many of which could be engineered to improve PHAs production.
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Affiliation(s)
- Claudia Velázquez-Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Guadalupe Espín
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Carlos Peña
- Departamento Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Daniel Segura
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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Global control of bacterial nitrogen and carbon metabolism by a PTS Ntr-regulated switch. Proc Natl Acad Sci U S A 2020; 117:10234-10245. [PMID: 32341157 DOI: 10.1073/pnas.1917471117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nitrogen-related phosphotransferase system (PTSNtr) of Rhizobium leguminosarum bv. viciae 3841 transfers phosphate from PEP via PtsP and NPr to two output regulators, ManX and PtsN. ManX controls central carbon metabolism via the tricarboxylic acid (TCA) cycle, while PtsN controls nitrogen uptake, exopolysaccharide production, and potassium homeostasis, each of which is critical for cellular adaptation and survival. Cellular nitrogen status modulates phosphorylation when glutamine, an abundant amino acid when nitrogen is available, binds to the GAF sensory domain of PtsP, preventing PtsP phosphorylation and subsequent modification of ManX and PtsN. Under nitrogen-rich, carbon-limiting conditions, unphosphorylated ManX stimulates the TCA cycle and carbon oxidation, while unphosphorylated PtsN stimulates potassium uptake. The effects are reversed with the phosphorylation of ManX and PtsN, occurring under nitrogen-limiting, carbon-rich conditions; phosphorylated PtsN triggers uptake and nitrogen metabolism, the TCA cycle and carbon oxidation are decreased, while carbon-storage polymers such as surface polysaccharide are increased. Deleting the GAF domain from PtsP makes cells "blind" to the cellular nitrogen status. PTSNtr constitutes a switch through which carbon and nitrogen metabolism are rapidly, and reversibly, regulated by protein:protein interactions. PTSNtr is widely conserved in proteobacteria, highlighting its global importance.
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Mærk M, Jakobsen ØM, Sletta H, Klinkenberg G, Tøndervik A, Ellingsen TE, Valla S, Ertesvåg H. Identification of Regulatory Genes and Metabolic Processes Important for Alginate Biosynthesis in Azotobacter vinelandii by Screening of a Transposon Insertion Mutant Library. Front Bioeng Biotechnol 2020; 7:475. [PMID: 32010681 PMCID: PMC6979010 DOI: 10.3389/fbioe.2019.00475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/23/2019] [Indexed: 12/23/2022] Open
Abstract
Azotobacter vinelandii produces the biopolymer alginate, which has a wide range of industrial and pharmaceutical applications. A random transposon insertion mutant library was constructed from A. vinelandii ATCC12518Tc in order to identify genes and pathways affecting alginate biosynthesis, and about 4,000 mutant strains were screened for altered alginate production. One mutant, containing a mucA disruption, displayed an elevated alginate production level, and several mutants with decreased or abolished alginate production were identified. The regulatory proteins AlgW and AmrZ seem to be required for alginate production in A. vinelandii, similarly to Pseudomonas aeruginosa. An algB mutation did however not affect alginate yield in A. vinelandii although its P. aeruginosa homolog is needed for full alginate production. Inactivation of the fructose phosphoenolpyruvate phosphotransferase system protein FruA resulted in a mutant that did not produce alginate when cultivated in media containing various carbon sources, indicating that this system could have a role in regulation of alginate biosynthesis. Furthermore, impaired or abolished alginate production was observed for strains with disruptions of genes involved in peptidoglycan biosynthesis/recycling and biosynthesis of purines, isoprenoids, TCA cycle intermediates, and various vitamins, suggesting that sufficient access to some of these compounds is important for alginate production. This hypothesis was verified by showing that addition of thiamine, succinate or a mixture of lysine, methionine and diaminopimelate increases alginate yield in the non-mutagenized strain. These results might be used in development of optimized alginate production media or in genetic engineering of A. vinelandii strains for alginate bioproduction.
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Affiliation(s)
- Mali Mærk
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | | | | | | | - Svein Valla
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Helga Ertesvåg
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
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12
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D'Arrigo I, Cardoso JGR, Rennig M, Sonnenschein N, Herrgård MJ, Long KS. Analysis of Pseudomonas putida growth on non-trivial carbon sources using transcriptomics and genome-scale modelling. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:87-97. [PMID: 30298597 DOI: 10.1111/1758-2229.12704] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 06/08/2023]
Abstract
Pseudomonas putida is characterized by a versatile metabolism and stress tolerance traits that allow the bacterium to cope with different environmental conditions. In this work, the mechanisms that allow P. putida KT2440 to grow in the presence of four sole carbon sources (glucose, citrate, ferulic acid, serine) were investigated by RNA sequencing (RNA-seq) and genome-scale metabolic modelling. Transcriptomic data identified uptake systems for the four carbon sources, and candidates were subjected to preliminary experimental characterization by mutant strain growth to test their involvement in substrate assimilation. The OpdH and BenF-like porins were involved in citrate and ferulic acid uptake respectively. The citrate transporter (encoded by PP_0147) and the TctABC system were important for supporting cell growth in citrate; PcaT and VanK were associated with ferulic acid uptake; and the ABC transporter AapJPQM was involved in serine transport. A genome-scale metabolic model of P. putida KT2440 was used to integrate and analyze the transcriptomic data, identifying and confirming the active catabolic pathways for each carbon source. This study reveals novel information about transporters that are essential for understanding bacterial adaptation to different environments.
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Affiliation(s)
- Isotta D'Arrigo
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
| | - João G R Cardoso
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
| | - Maja Rennig
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
| | - Nikolaus Sonnenschein
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
| | - Markus J Herrgård
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
| | - Katherine S Long
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, DK-2800, Kongens Lyngby, Denmark
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13
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López-Pliego L, García-Ramírez L, Cruz-Gómez EA, Domínguez-Ojeda P, López-Pastrana A, Fuentes-Ramírez LE, Núñez C, Castañeda M. Transcriptional Study of the RsmZ-sRNAs and Their Relationship to the Biosynthesis of Alginate and Alkylresorcinols in Azotobacter vinelandii. Mol Biotechnol 2018; 60:670-680. [DOI: 10.1007/s12033-018-0102-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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14
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Löwe H, Sinner P, Kremling A, Pflüger-Grau K. Engineering sucrose metabolism in Pseudomonas putida highlights the importance of porins. Microb Biotechnol 2018; 13:97-106. [PMID: 29808622 PMCID: PMC6922520 DOI: 10.1111/1751-7915.13283] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 12/19/2022] Open
Abstract
Using agricultural wastes as a substrate for biotechnological processes is of great interest in industrial biotechnology. A prerequisite for using these wastes is the ability of the industrially relevant microorganisms to metabolize the sugars present therein. Therefore, many metabolic engineering approaches are directed towards widening the substrate spectrum of the workhorses of industrial biotechnology like Escherichia coli, yeast or Pseudomonas putida. For instance, neither xylose or arabinose from cellulosic residues, nor sucrose, the main sugar in waste molasses, can be metabolized by most E. coli and P. putida wild types. We evaluated a new, so far uncharacterized gene cluster for sucrose metabolism from Pseudomonas protegens Pf‐5 and showed that it enables P. putida to grow on sucrose as the sole carbon and energy source. Even when integrated into the genome of P. putida, the resulting strain grew on sucrose at rates similar to the rate of the wild type on glucose – making it the fastest growing, plasmid‐free P. putida strain known so far using sucrose as substrate. Next, we elucidated the role of the porin, an orthologue of the sucrose porin ScrY, in the gene cluster and found that in P. putida, a porin is needed for sucrose transport across the outer membrane. Consequently, native porins were not sufficient to allow unlimited growth on sucrose. Therefore, we concluded that the outer membrane can be a considerable barrier for substrate transport, depending on strain, genotype and culture conditions, all of which should be taken into account in metabolic engineering approaches. We additionally showed the potential of the engineered P. putida strains by growing them on molasses with efficiencies twice as high as obtained with the wild‐type P. putida. This can be seen as a further step towards the production of low‐value chemicals and biofuels with P. putida from alternative and more affordable substrates in the future.
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Affiliation(s)
- Hannes Löwe
- Systems Biotechnology, Technical University of Munich, 85748, Garching, Germany
| | - Peter Sinner
- Systems Biotechnology, Technical University of Munich, 85748, Garching, Germany
| | - Andreas Kremling
- Systems Biotechnology, Technical University of Munich, 85748, Garching, Germany
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15
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Trends in the biomanufacture of polyhydroxyalkanoates with focus on downstream processing. Int J Biol Macromol 2018; 107:762-778. [DOI: 10.1016/j.ijbiomac.2017.09.054] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/30/2017] [Accepted: 09/15/2017] [Indexed: 11/18/2022]
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16
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Wang Y, Chung A, Chen GQ. Synthesis of Medium-Chain-Length Polyhydroxyalkanoate Homopolymers, Random Copolymers, and Block Copolymers by an Engineered Strain of Pseudomonas entomophila. Adv Healthc Mater 2017; 6. [PMID: 28128887 DOI: 10.1002/adhm.201601017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 12/20/2016] [Indexed: 11/11/2022]
Abstract
Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), widely used in medical area, are commonly synthesized by Pseudomonas spp. This study tries to use β-oxidation pathways engineered P. entomophila to achieve single source of a series of mcl-monomers for microbial production of PHA homopolymers. The effort is proven successful for the first time to obtain a wide range of mcl-PHA homopolymers from engineered P. entomophila LAC23 grown on various fatty acids, respectively, ranging from poly(3-hydroxyheptanoate) to poly(3-hydroxytetradecanoate). Effects of a PHA monomer chain length on thermal and crystallization properties including the changes of Tm , Tg , and Td5% are investigated. Additionally, strain LAC23 is used to synthesize random copolymers of 3-hydroxyoctanoate (3HO) and 3-hydroxydodecanoate (3HDD) or 3-hydroxytetradecanoates, their compositions could be controlled by adjusting the ratios of two related fatty acids. Meanwhile, block copolymer P(3HO)-b-P(3HDD) is synthesized by the same strain. It is found for the first time that even- and odd number mcl-PHA homopolymers have different physical properties. When the gene of the PHA synthase in the engineered P. entomophila is replaced by phaC from Aeromonas hydrophila 4AK4, poly(3-hydroxybutyrate-co-30 mol%-3-hydroxyhexanoate) is synthesized. Therefore, P. entomophila can be used to synthesize the whole range of PHA (C7-C14) homopolymers, random- and block copolymers.
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Affiliation(s)
- Ying Wang
- School of Life Science; Tsinghua University; Beijing 100084 China
- Tsinghua-Peking Center for Life Sciences; Tsinghua University; Beijing 100084 China
- Center for Synthetic and Systems Biology; Tsinghua University; Beijing 100084 China
- Department of Biological Engineering; School of Life Science; Beijing Institute of Technology; Beijing 100081 China
| | - Ahleum Chung
- School of Life Science; Tsinghua University; Beijing 100084 China
| | - Guo-Qiang Chen
- School of Life Science; Tsinghua University; Beijing 100084 China
- Tsinghua-Peking Center for Life Sciences; Tsinghua University; Beijing 100084 China
- Center for Synthetic and Systems Biology; Tsinghua University; Beijing 100084 China
- Center for Nano and Micro Mechanics; Tsinghua University; Beijing 100084 China
- MOE Key Lab for Industrial Biocatalysis; Tsinghua University; Beijing 100084 China
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17
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Ertesvåg H, Sletta H, Senneset M, Sun YQ, Klinkenberg G, Konradsen TA, Ellingsen TE, Valla S. Identification of genes affecting alginate biosynthesis in Pseudomonas fluorescens by screening a transposon insertion library. BMC Genomics 2017; 18:11. [PMID: 28049432 PMCID: PMC5210274 DOI: 10.1186/s12864-016-3467-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/23/2016] [Indexed: 12/16/2022] Open
Abstract
Background Polysaccharides often are necessary components of bacterial biofilms and capsules. Production of these biopolymers constitutes a drain on key components in the central carbon metabolism, but so far little is known concerning if and how the cells divide their resources between cell growth and production of exopolysaccharides. Alginate is an industrially important linear polysaccharide synthesized from fructose 6-phosphate by several bacterial species. The aim of this study was to identify genes that are necessary for obtaining a normal level of alginate production in alginate-producing Pseudomonas fluorescens. Results Polysaccharide biosynthesis is costly, since it utilizes nucleotide sugars and sequesters carbon. Consequently, transcription of the genes necessary for polysaccharide biosynthesis is usually tightly regulated. In this study we used an engineered P. fluorescens SBW25 derivative where all genes encoding the proteins needed for biosynthesis of alginate from fructose 6-phosphate and export of the polymer are expressed from inducible Pm promoters. In this way we would avoid identification of genes merely involved in regulating the expression of the alginate biosynthetic genes. The engineered strain was subjected to random transposon mutagenesis and a library of about 11500 mutants was screened for strains with altered alginate production. Identified inactivated genes were mainly found to encode proteins involved in metabolic pathways related to uptake and utilization of carbon, nitrogen and phosphor sources, biosynthesis of purine and tryptophan and peptidoglycan recycling. Conclusions The majority of the identified mutants resulted in diminished alginate biosynthesis while cell yield in most cases were less affected. In some cases, however, a higher final cell yield were measured. The data indicate that when the supplies of fructose 6-phosphate or GTP are diminished, less alginate is produced. This should be taken into account when bacterial strains are designed for industrial polysaccharide production. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3467-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Helga Ertesvåg
- Department of Biotechnology, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
| | | | - Mona Senneset
- Department of Biotechnology, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.,SINTEF Materials and Chemistry, Trondheim, Norway
| | - Yi-Qian Sun
- Department of Biotechnology, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | | | - Svein Valla
- Department of Biotechnology, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
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18
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Poblete-Castro I, Borrero-de Acuña JM, Nikel PI, Kohlstedt M, Wittmann C. Host Organism: Pseudomonas putida. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Ignacio Poblete-Castro
- Universidad Andrés Bello; Center for Bioinformatics and Integrative Biology, Biosystems Engineering Laboratory, Faculty of Biological Sciences; Av. República 239 8340176 Santiago de Chile Chile
| | - José M. Borrero-de Acuña
- Universidad Andrés Bello; Center for Bioinformatics and Integrative Biology, Biosystems Engineering Laboratory, Faculty of Biological Sciences; Av. República 239 8340176 Santiago de Chile Chile
| | - Pablo I. Nikel
- Systems and Synthetic Biology Program; National Spanish Center for Biotechnology (CNB-CSIC); Calle Darwin, 3 28049 Madrid, Spain
| | - Michael Kohlstedt
- Saarland University; Institute of Systems Biology, Biosciences; Campus A1.5 66123 Saarbrücken, Germany
| | - Christoph Wittmann
- Saarland University; Institute of Systems Biology, Biosciences; Campus A1.5 66123 Saarbrücken, Germany
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19
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Derkaoui M, Antunes A, Poncet S, Nait Abdallah J, Joyet P, Mazé A, Henry C, Taha MK, Deutscher J, Deghmane AE. The phosphocarrier protein HPr of Neisseria meningitidis interacts with the transcription regulator CrgA and its deletion affects capsule production, cell adhesion, and virulence. Mol Microbiol 2016; 100:788-807. [PMID: 26858137 DOI: 10.1111/mmi.13349] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2016] [Indexed: 01/08/2023]
Abstract
The bacterial phosphotransferase system (PTS) transports and phosphorylates sugars, but also carries out numerous regulatory functions. The β-proteobacterium Neisseria meningitidis possesses an incomplete PTS unable to transport carbon sources because it lacks a membrane component. Nevertheless, the residual phosphorylation cascade is functional and the meningococcal PTS was therefore expected to carry out regulatory roles. Interestingly, a ΔptsH mutant (lacks the PTS protein HPr) exhibited reduced virulence in mice and after intraperitoneal challenge it was rapidly cleared from the bloodstream of BALB/c mice. The rapid clearance correlates with lower capsular polysaccharide production by the ΔptsH mutant, which is probably also responsible for its increased adhesion to Hec-1-B epithelial cells. In addition, compared to the wild-type strain more apoptotic cells were detected when Hec-1-B cells were infected with the ΔptsH strain. Coimmunoprecipitation revealed an interaction of HPr and P-Ser-HPr with the LysR type transcription regulator CrgA, which among others controls its own expression. Moreover, ptsH deletion caused increased expression of a ΦcrgA-lacZ fusion. Finally, the presence of HPr or phospho-HPr's during electrophoretic mobility shift assays enhanced the affinity of CrgA for its target sites preceding crgA and pilE, but HPr did not promote CrgA binding to the sia and pilC1 promoter regions.
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Affiliation(s)
- Meriem Derkaoui
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.,Institut Pasteur, Unité des Infections Bactériennes Invasives, 75000, Paris Cedex, France
| | - Ana Antunes
- Institut Pasteur, Unité des Infections Bactériennes Invasives, 75000, Paris Cedex, France
| | - Sandrine Poncet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Jamila Nait Abdallah
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.,Institut Pasteur, Unité des Infections Bactériennes Invasives, 75000, Paris Cedex, France
| | - Philippe Joyet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Alain Mazé
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Céline Henry
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Muhamed-Kheir Taha
- Institut Pasteur, Unité des Infections Bactériennes Invasives, 75000, Paris Cedex, France
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.,Centre National de la Recherche Scientifique, UMR8261, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Ala-Eddine Deghmane
- Institut Pasteur, Unité des Infections Bactériennes Invasives, 75000, Paris Cedex, France
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Li YZ, Wang D, Feng XY, Jiao J, Chen WX, Tian CF. Genetic Analysis Reveals the Essential Role of Nitrogen Phosphotransferase System Components in Sinorhizobium fredii CCBAU 45436 Symbioses with Soybean and Pigeonpea Plants. Appl Environ Microbiol 2016; 82:1305-15. [PMID: 26682851 PMCID: PMC4751829 DOI: 10.1128/aem.03454-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/10/2015] [Indexed: 11/20/2022] Open
Abstract
The nitrogen phosphotransferase system (PTS(Ntr)) consists of EI(Ntr), NPr, and EIIA(Ntr). The active phosphate moiety derived from phosphoenolpyruvate is transferred through EI(Ntr) and NPr to EIIA(Ntr). Sinorhizobium fredii can establish a nitrogen-fixing symbiosis with the legume crops soybean (as determinate nodules) and pigeonpea (as indeterminate nodules). In this study, S. fredii strains with mutations in ptsP and ptsO (encoding EI(Ntr) and NPr, respectively) formed ineffective nodules on soybeans, while a strain with a ptsN mutation (encoding EIIA(Ntr)) was not defective in symbiosis with soybeans. Notable reductions in the numbers of bacteroids within each symbiosome and of poly-β-hydroxybutyrate granules in bacteroids were observed in nodules infected by the ptsP or ptsO mutant strains but not in those infected with the ptsN mutant strain. However, these defects of the ptsP and ptsO mutant strains were recovered in ptsP ptsN and ptsO ptsN double-mutant strains, implying a negative role of unphosphorylated EIIA(Ntr) in symbiosis. Moreover, the symbiotic defect of the ptsP mutant was also recovered by expressing EI(Ntr) with or without the GAF domain, indicating that the putative glutamine-sensing domain GAF is dispensable in symbiotic interactions. The critical role of PTS(Ntr) in symbiosis was also observed when related PTS(Ntr) mutant strains of S. fredii were inoculated on pigeonpea plants. Furthermore, nodule occupancy and carbon utilization tests suggested that multiple outputs could be derived from components of PTS(Ntr) in addition to the negative role of unphosphorylated EIIA(Ntr).
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Affiliation(s)
- Yue Zhen Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
| | - Dan Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
| | - Xue Ying Feng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
| | - Jian Jiao
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
| | - Wen Xin Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
| | - Chang Fu Tian
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, and Rhizobium Research Center, China Agricultural University, Beijing, ChinaUniversity of Wisconsin-Madison
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21
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Liu CC, Zhang LL, An J, Chen B, Yang H. Recent strategies for efficient production of polyhydroxyalkanoates by micro-organisms. Lett Appl Microbiol 2015; 62:9-15. [PMID: 26482840 DOI: 10.1111/lam.12511] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/29/2015] [Accepted: 10/12/2015] [Indexed: 12/15/2022]
Affiliation(s)
- C.-C. Liu
- Translational Medicine Center; Hong-Hui Hospital; Xi'an Jiaotong University College of Medicine; Xi'an China
| | - L.-L. Zhang
- Translational Medicine Center; Hong-Hui Hospital; Xi'an Jiaotong University College of Medicine; Xi'an China
| | - J. An
- Translational Medicine Center; Hong-Hui Hospital; Xi'an Jiaotong University College of Medicine; Xi'an China
| | - B. Chen
- Translational Medicine Center; Hong-Hui Hospital; Xi'an Jiaotong University College of Medicine; Xi'an China
| | - H. Yang
- Translational Medicine Center; Hong-Hui Hospital; Xi'an Jiaotong University College of Medicine; Xi'an China
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22
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Wolf S, Pflüger-Grau K, Kremling A. Modeling the Interplay of Pseudomonas putida EIIA Ntr with the Potassium Transporter KdpFABC. J Mol Microbiol Biotechnol 2015; 25:178-94. [DOI: 10.1159/000381214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The nitrogen phosphotransferase system (PTS<sup>Ntr</sup>) of <i>Pseudomonas putida</i> is a key regulatory device that participates in controlling many physiological processes in a posttranscriptional fashion. One of the target functions of the PTS<sup>Ntr</sup> is the regulation of potassium transport. This is mediated by the direct interaction of one of its components with the sensor kinase KdpD of the two-component system controlling transcription of the <i>kdpFABC</i> genes. From a detailed experimental analysis of the activity of the <i>kdpF</i> promoter in <i>P. putida</i> wild-type and <i>pts</i> mutant strains with varying potassium concentrations, we had highly time-resolved data at hand, describing the influence of the PTS<sup>Ntr</sup> on the transcription of the KdpFABC potassium transporter. Here, this data was used to construct a mathematical model based on a black box approach. The model was able to describe the data quantitatively with convincing accuracy. The qualitative interpretation of the model allowed the prediction of two general points describing the interplay between the PTS<sup>Ntr</sup> and the KdpFABC potassium transporter: (1) the influence of cell number on the performance of the <i>kdpF</i> promoter is mainly by dilution by growth and (2) potassium uptake is regulated not only by the activity of the KdpD/KdpE two-component system (in turn influenced by PtsN). An additional controller with integrative behavior is predicted by the model structure. This suggests the presence of a novel physiological mechanism during regulation of potassium uptake with the KdpFABC transporter and may serve as a starting point for further investigations.
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23
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Lee J, Park YH, Kim YR, Seok YJ, Lee CR. Dephosphorylated NPr is involved in an envelope stress response of Escherichia coli. MICROBIOLOGY-SGM 2015; 161:1113-1123. [PMID: 25701731 PMCID: PMC4635465 DOI: 10.1099/mic.0.000056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/10/2015] [Indexed: 01/20/2023]
Abstract
Besides the canonical phosphoenolpyruvate-dependent phosphotransferase system (PTS) for carbohydrate transport, most Proteobacteria possess the so-called nitrogen PTS (PTSNtr) that transfers a phosphate group from phosphoenolpyruvate (PEP) over enzyme INtr (EINtr) and NPr to enzyme IIANtr (EIIANtr). The PTSNtr lacks membrane-bound components and functions exclusively in a regulatory capacity. While EIIANtr has been implicated in a variety of cellular processes such as potassium homeostasis, phosphate starvation, nitrogen metabolism, carbon metabolism, regulation of ABC transporters and poly-β-hydroxybutyrate accumulation in many Proteobacteria, the only identified role of NPr is the regulation of biosynthesis of the lipopolysaccharide (LPS) layer by direct interaction with LpxD in Escherichia coli. In this study, we provide another phenotype related to NPr. Several lines of evidence demonstrate that E. coli strains with increased levels of dephosphorylated NPr are sensitive to envelope stresses, such as osmotic, ethanol and SDS stresses, and these phenotypes are independent of LpxD. The C-terminal region of NPr plays an important role in sensitivity to envelope stresses. Thus, our data suggest that the dephospho-form of NPr affects adaptation to envelope stresses through a C-terminus-dependent mechanism.
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Affiliation(s)
- Jaeseop Lee
- Department of Biological Sciences, Myongji University, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Young-Ha Park
- Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Yeon-Ran Kim
- Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Yeong-Jae Seok
- Department of Biophysics and Chemical Biology, Seoul National University, Seoul 151-742, Republic of Korea.,Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Chang-Ro Lee
- Department of Biological Sciences, Myongji University, Yongin, Gyeonggido 449-728, Republic of Korea
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24
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Prieto A, Escapa IF, Martínez V, Dinjaski N, Herencias C, de la Peña F, Tarazona N, Revelles O. A holistic view of polyhydroxyalkanoate metabolism inPseudomonas putida. Environ Microbiol 2015; 18:341-57. [DOI: 10.1111/1462-2920.12760] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 12/12/2014] [Accepted: 12/20/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Auxiliadora Prieto
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Isabel F. Escapa
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Virginia Martínez
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Nina Dinjaski
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Cristina Herencias
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Fernando de la Peña
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Natalia Tarazona
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Olga Revelles
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
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25
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López NI, Pettinari MJ, Nikel PI, Méndez BS. Polyhydroxyalkanoates: Much More than Biodegradable Plastics. ADVANCES IN APPLIED MICROBIOLOGY 2015; 93:73-106. [PMID: 26505689 DOI: 10.1016/bs.aambs.2015.06.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bacterial polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in central metabolism, as they act as dynamic reservoirs of carbon and reducing equivalents. These polymers have a number of technical applications since they exhibit thermoplastic and elastomeric properties, making them attractive as a replacement of oil-derived materials. PHAs are accumulated under conditions of nutritional imbalance (usually an excess of carbon source with respect to a limiting nutrient, such as nitrogen or phosphorus). The cycle of PHA synthesis and degradation has been recognized as an important physiological feature when these biochemical pathways were originally described, yet its role in bacterial processes as diverse as global regulation and cell survival is just starting to be appreciated in full. In the present revision, the complex regulation of PHA synthesis and degradation at the transcriptional, translational, and metabolic levels are explored by analyzing examples in natural producer bacteria, such as Pseudomonas species, as well as in recombinant Escherichia coli strains. The ecological role of PHAs, together with the interrelations with other polymers and extracellular substances, is also discussed, along with their importance in cell survival, resistance to several types of environmental stress, and planktonic-versus-biofilm lifestyle. Finally, bioremediation and plant growth promotion are presented as examples of environmental applications in which PHA accumulation has successfully been exploited.
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Fonseca P, de la Peña F, Prieto MA. A role for the regulator PsrA in the polyhydroxyalkanoate metabolism of Pseudomonas putida KT2440. Int J Biol Macromol 2014; 71:14-20. [DOI: 10.1016/j.ijbiomac.2014.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/31/2014] [Accepted: 04/05/2014] [Indexed: 10/25/2022]
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Fruit pomace and waste frying oil as sustainable resources for the bioproduction of medium-chain-length polyhydroxyalkanoates. Int J Biol Macromol 2014; 71:42-52. [DOI: 10.1016/j.ijbiomac.2014.05.061] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 11/22/2022]
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28
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Pflüger-Grau K, de Lorenzo V. From the phosphoenolpyruvate phosphotransferase system to selfish metabolism: a story retraced in Pseudomonas putida. FEMS Microbiol Lett 2014; 356:144-53. [PMID: 24801646 DOI: 10.1111/1574-6968.12459] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 04/28/2014] [Accepted: 04/30/2014] [Indexed: 12/17/2022] Open
Abstract
Although DNA is the ultimate repository of biological information, deployment of its instructions is constrained by the metabolic and physiological status of the cell. To this end, bacteria have evolved intricate devices that connect exogenous signals (e.g. nutrients, physicochemical conditions) with endogenous conditions (metabolic fluxes, biochemical networks) that coordinately influence expression or performance of a large number of cellular functions. The phosphoenolpyruvate:carbohydrate-phosphotransferase system (PTS) is a bacterial multi-protein phosphorylation chain which computes extracellular (e.g. sugars) and intracellular (e.g. phosphoenolpyruvate, nitrogen) signals and translates them into post-translational regulation of target activities through protein-protein interactions. The PTS of Pseudomonas putida KT2440 encompasses one complete sugar (fructose)-related system and the three enzymes that form the so-called nitrogen-related PTS (PTS(N) (tr) ), which lacks connection to transport of substrates. These two PTS branches cross-talk to each other, as the product of the fruB gene (a polyprotein EI-HPr-EIIA) can phosphorylate PtsN (EIIA(N) (tr) ) in vivo. This gives rise to a complex actuator device where diverse physiological inputs are ultimately translated into phosphorylation or not of PtsN (EIIA(N) (tr) ) which, in turn, checks the activity of key metabolic and regulatory proteins. Such a control of bacterial physiology highlights the prominence of biochemical homeostasis over genetic ruling -and not vice versa.
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Li S, Cai L, Wu L, Zeng G, Chen J, Wu Q, Chen GQ. Microbial synthesis of functional homo-, random, and block polyhydroxyalkanoates by β-oxidation deleted Pseudomonas entomophila. Biomacromolecules 2014; 15:2310-9. [PMID: 24830358 DOI: 10.1021/bm500669s] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functional polyhydroxyalkanoates (PHAs) allow chemical modifications to widen PHA diversity, promising to increase values of these biodegradable and biocompatible polyesters. Among functional PHAs, unsaturated PHA site chains can be easily grafted to add chemical groups, and to cross-link with other PHA polymer chains. However, it has been very difficult to obtain structurally controllable functional homo-, random, or block PHA. For the first time, a β-oxidation deleted Pseudomonas entomophila was used to successfully synthesize random copolymers of 3-hydroxydodecanoate (3HDD) and 3-hydroxy-9-decenoate (3H9D). Compositions of the random copolymers P(3HDD-co-3H9D) can be adjusted by ratios of dodecanoic acid (DDA) to 9-decenol (9DEO) fed to the culture of P. entomophila. Homopolymer P3H9D was formed when only 9DEO was added to the culture. Diblock copolymers of P3HDD-b-P3H9D were produced by feeding DDA as the first precursor to form a P3HDD block followed by adding 9DEO as the second precursor to form a second P3H9D block. It was demonstrated that random copolymers P(3HDD-co-3H9D) could be crossed-linked under UV-radiation due to the presence of the unsaturated bonds. Thermal and mechanical characterizations of the above homo-, random, and diblock PHA polymers were conducted. It was found that the diblock polymer P3HDD-b-P3H9D increased at least 2-fold on Young's modulus compared with its random copolymers consisting of similar 3HDD/3H9D ratios. This study demonstrates that PHA functionality could be controlled to meet various requirements.
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Affiliation(s)
- Shijun Li
- MOE Key Lab of Bioinformatics, Department of Biological Science and Biotechnology, School of Life Science, Tsinghua-Peking Center for Life Sciences, Tsinghua University , Beijing 100084, China
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Karstens K, Zschiedrich CP, Bowien B, Stülke J, Görke B. Phosphotransferase protein EIIANtr interacts with SpoT, a key enzyme of the stringent response, in Ralstonia eutropha H16. MICROBIOLOGY-SGM 2014; 160:711-722. [PMID: 24515609 DOI: 10.1099/mic.0.075226-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
EIIA(Ntr) is a member of a truncated phosphotransferase (PTS) system that serves regulatory functions and exists in many Proteobacteria in addition to the sugar transport PTS. In Escherichia coli, EIIA(Ntr) regulates K(+) homeostasis through interaction with the K(+) transporter TrkA and sensor kinase KdpD. In the β-Proteobacterium Ralstonia eutropha H16, EIIA(Ntr) influences formation of the industrially important bioplastic poly(3-hydroxybutyrate) (PHB). PHB accumulation is controlled by the stringent response and induced under conditions of nitrogen deprivation. Knockout of EIIA(Ntr) increases the PHB content. In contrast, absence of enzyme I or HPr, which deliver phosphoryl groups to EIIA(Ntr), has the opposite effect. To clarify the role of EIIA(Ntr) in PHB formation, we screened for interacting proteins that co-purify with Strep-tagged EIIA(Ntr) from R. eutropha cells. This approach identified the bifunctional ppGpp synthase/hydrolase SpoT1, a key enzyme of the stringent response. Two-hybrid and far-Western analyses confirmed the interaction and indicated that only non-phosphorylated EIIA(Ntr) interacts with SpoT1. Interestingly, this interaction does not occur between the corresponding proteins of E. coli. Vice versa, interaction of EIIA(Ntr) with KdpD appears to be absent in R. eutropha, although R. eutropha EIIA(Ntr) can perfectly substitute its homologue in E. coli in regulation of KdpD activity. Thus, interaction with KdpD might be an evolutionary 'ancient' task of EIIA(Ntr) that was subsequently replaced by interaction with SpoT1 in R. eutropha. In conclusion, EIIA(Ntr) might integrate information about nutritional status, as reflected by its phosphorylation state, into the stringent response, thereby controlling cellular PHB content in R. eutropha.
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Affiliation(s)
- Katja Karstens
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077 Göttingen, Germany
| | - Christopher P Zschiedrich
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077 Göttingen, Germany
| | - Botho Bowien
- Department of Molecular Physiology, Institute of Microbiology and Genetics, Georg-August-University, 37077 Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077 Göttingen, Germany
| | - Boris Görke
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, Center of Molecular Biology, University of Vienna, 1030 Vienna, Austria.,Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, 37077 Göttingen, Germany
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Benzene containing polyhydroxyalkanoates homo- and copolymers synthesized by genome edited Pseudomonas entomophila. SCIENCE CHINA-LIFE SCIENCES 2013; 57:4-10. [DOI: 10.1007/s11427-013-4596-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/25/2013] [Indexed: 10/25/2022]
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A role for EIIA Ntr in controlling fluxes in the central metabolism of E. coli K12. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2879-2889. [DOI: 10.1016/j.bbamcr.2013.07.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/04/2013] [Accepted: 07/15/2013] [Indexed: 11/21/2022]
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La Rosa R, de la Peña F, Prieto MA, Rojo F. The Crc protein inhibits the production of polyhydroxyalkanoates inPseudomonas putidaunder balanced carbon/nitrogen growth conditions. Environ Microbiol 2013; 16:278-90. [DOI: 10.1111/1462-2920.12303] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/02/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Ruggero La Rosa
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC; Darwin 3 Cantoblanco 28049 Madrid Spain
| | - Fernando de la Peña
- Departamento de Biología Ambiental; Centro de Investigaciones Biológicas, CSIC; Ramiro de Maeztu 9 28040 Madrid Spain
| | - María Axiliadora Prieto
- Departamento de Biología Ambiental; Centro de Investigaciones Biológicas, CSIC; Ramiro de Maeztu 9 28040 Madrid Spain
| | - Fernando Rojo
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC; Darwin 3 Cantoblanco 28049 Madrid Spain
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Inoue K, Miyazaki R, Ohtsubo Y, Nagata Y, Tsuda M. Inhibitory effect ofPseudomonas putidanitrogen-related phosphotransferase system on conjugative transfer of IncP-9 plasmid fromEscherichia coli. FEMS Microbiol Lett 2013; 345:102-9. [DOI: 10.1111/1574-6968.12188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 05/06/2013] [Accepted: 05/29/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- Kei Inoue
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai; Japan
| | - Ryo Miyazaki
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai; Japan
| | - Yoshiyuki Ohtsubo
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai; Japan
| | - Yuji Nagata
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai; Japan
| | - Masataka Tsuda
- Department of Environmental Life Sciences; Graduate School of Life Sciences; Tohoku University; Sendai; Japan
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Arias S, Bassas-Galia M, Molinari G, Timmis KN. Tight coupling of polymerization and depolymerization of polyhydroxyalkanoates ensures efficient management of carbon resources in Pseudomonas putida. Microb Biotechnol 2013; 6:551-63. [PMID: 23445364 PMCID: PMC3918157 DOI: 10.1111/1751-7915.12040] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 11/15/2012] [Accepted: 01/12/2013] [Indexed: 11/28/2022] Open
Abstract
Environmental microbes oscillate between feast and famine and need to carefully manage utilization, storage and conversion of reserve products to exploitable sources of carbon and energy. Polyhydroxyalkanoates (PHAs) are storage polymers that serve bacteria as sources of food materials under physiological conditions of carbon demand. In order to obtain insights into the role of PHA depolymerase (PhaZ) and its relationship to a PHA polymerase (PhaC2) in the carbon management activity of Pseudomonas putida strain U, we created a polymerase hyperexpression strain and a depolymerase knockout mutant of this strain, and examined their synthesis of PHA and expression of their PHA genes. This study revealed that hyperexpression of PhaC2 led to the accumulation of higher amounts of PHA (44%wt) than in the wild-type strain (24%wt) after 24 h of cultivation, which then returned to wild-type levels by 48 h, as a result of elevated depolymerization. The phaZ mutant, however, accumulated higher levels of PHA than the parental strain (62%wt), which were maintained for at least 96 h. Transcriptional analysis of the pha cluster by RT-PCR revealed that PHA operon proteins, including depolymerase, are expressed from the beginning of the growth phase. Hyperexpression of the PhaC2 polymerase was accompanied by an increase in the expression of the PhaZ depolymerase and a decrease in expression of another PHA polymerase, PhaC1. This suggests tight regulatory coupling of PHA polymerase and depolymerase activities that act in synergy, and in concert with other PHA proteins, to provide dynamic PHA granule synthesis and remodelling that rapidly and sensitively respond to changes in availability of carbon and the physiological-metabolic needs of the cell, to ensure optimal carbon resource management.
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Affiliation(s)
- Sagrario Arias
- Environmental Microbiology Laboratory, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany.
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Liu H, Luo Y, Han J, Wu J, Wu Z, Feng D, Cai S, Li M, Liu J, Zhou J, Xiang H. Proteome Reference Map of Haloarcula hispanica and Comparative Proteomic and Transcriptomic Analysis of Polyhydroxyalkanoate Biosynthesis under Genetic and Environmental Perturbations. J Proteome Res 2013; 12:1300-15. [PMID: 23301558 DOI: 10.1021/pr300969m] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Hailong Liu
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Yuanming Luo
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Jing Han
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Jinhua Wu
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Zhenfang Wu
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Deqin Feng
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Shuangfeng Cai
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Ming Li
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Jingfang Liu
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Jian Zhou
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Hua Xiang
- State Key
Laboratory of Microbial Resources, Institute
of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
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Erni B. The bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS): an interface between energy and signal transduction. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2012. [DOI: 10.1007/s13738-012-0185-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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38
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Kremling A, Pflüger-Grau K, Chavarría M, Puchalka J, dos Santos VM, de Lorenzo V. Modeling and analysis of flux distributions in the two branches of the phosphotransferase system in Pseudomonas putida. BMC SYSTEMS BIOLOGY 2012; 6:149. [PMID: 23216700 PMCID: PMC3562155 DOI: 10.1186/1752-0509-6-149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 10/31/2012] [Indexed: 11/30/2022]
Abstract
Background Signal transduction plays a fundamental role in the understanding of cellular physiology. The bacterial phosphotransferase system (PTS) together with the PEP/pyruvate node in central metabolism represents a signaling unit that acts as a sensory element and measures the activity of the central metabolism. Pseudomonas putida possesses two PTS branches, the C-branch (PTSFru) and a second branch (PTSNtr), which communicate with each other by phosphate exchange. Recent experimental results showed a cross talk between the two branches. However, the functional role of the crosstalk remains open. Results A mathematical model was set up to describe the available data of the state of phosphorylation of PtsN, one of the PTS proteins, for different environmental conditions and different strain variants. Additionally, data from flux balance analysis was used to determine some of the kinetic parameters of the involved reactions. Based on the calculated and estimated parameters, the flux distribution during growth of the wild type strain on fructose could be determined. Conclusion Our calculations show that during growth of the wild type strain on the PTS substrate fructose, the major part of the phosphoryl groups is provided by the second branch of the PTS. This theoretical finding indicates a new role of the second branch of the PTS and will serve as a basis for further experimental studies.
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Affiliation(s)
- Andreas Kremling
- Fachgebiet Systembiotechnologie, Technische Universität München, Garching b, München, Germany.
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39
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Chavarría M, Fuhrer T, Sauer U, Pflüger-Grau K, de Lorenzo V. Cra regulates the cross-talk between the two branches of the phosphoenolpyruvate : phosphotransferase system of Pseudomonas putida. Environ Microbiol 2012; 15:121-32. [PMID: 22708906 DOI: 10.1111/j.1462-2920.2012.02808.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The gene that encodes the catabolite repressor/activator, Cra (FruR), of Pseudomonas putida is divergent from the fruBKA operon for the uptake of fructose via the phosphoenolpyruvate : carbohydrate phosphotransferase system (PTS(Fru)). The expression of the fru cluster has been studied in cells growing on substrates that change the intracellular concentrations of fructose-1-P (F1P), the principal metabolic intermediate that counteracts the DNA-binding ability of Cra on an upstream operator. While the levels of the regulator were not affected by any of the growth conditions tested, the transcription of fruB was stimulated by fructose but not by the gluconeogenic substrate, succinate. The analysis of the P(fruB) promoter activity in a strain lacking the Cra protein and the determination of key metabolites revealed that this regulator represses the expression of PTS(Fru) in a fashion that is dependent on the endogenous concentrations of F1P. Because FruB (i.e. the EI-HPr-EIIA(Fru) polyprotein) can deliver a high-energy phosphate to the EIIA(Ntr) (PtsN) enzyme of the PTS(Ntr) branch, the cross-talk between the two phosphotransferase systems was examined under metabolic regimes that allowed for the high or low transcription of the fruBKA operon. While fructose caused cross-talk, succinate prevented it almost completely. Furthermore, PtsN phosphorylation by FruB occurred in a Δcra mutant regardless of growth conditions. These results traced the occurrence of the cross-talk to intracellular pools of Cra effectors, in particular F1P. The Cra/F1P duo seems to not only control the expression of the PTS(Fru) but also checks the activity of the PTS(Ntr) in vivo.
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Affiliation(s)
- Max Chavarría
- Systems Biology Program, Centro Nacional de Biotecnología, 28049 Cantoblanco-Madrid, Spain
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Escapa IF, del Cerro C, García JL, Prieto MA. The role of GlpR repressor inPseudomonas putidaKT2440 growth and PHA production from glycerol. Environ Microbiol 2012; 15:93-110. [DOI: 10.1111/j.1462-2920.2012.02790.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Regulatory tasks of the phosphoenolpyruvate-phosphotransferase system of Pseudomonas putida in central carbon metabolism. mBio 2012; 3:mBio.00028-12. [PMID: 22434849 PMCID: PMC3312210 DOI: 10.1128/mbio.00028-12] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Two branches of the phosphoenolpyruvate-phosphotransferase system (PTS) operate in the soil bacterium Pseudomonas putida KT2440. One branch encompasses a complete set of enzymes for fructose intake (PTSFru), while the other (N-related PTS, or PTSNtr) controls various cellular functions unrelated to the transport of carbohydrates. The potential of these two systems for regulating central carbon catabolism has been investigated by measuring the metabolic fluxes of isogenic strains bearing nonpolar mutations in PTSFru or PTSNtr genes and grown on either fructose (a PTS substrate) or glucose, the transport of which is not governed by the PTS in this bacterium. The flow of carbon from each sugar was distinctly split between the Entner-Doudoroff, pentose phosphate, and Embden-Meyerhof-Parnas pathways in a ratio that was maintained in each of the PTS mutants examined. However, strains lacking PtsN (EIIANtr) displayed significantly higher fluxes in the reactions of the pyruvate shunt, which bypasses malate dehydrogenase in the TCA cycle. This was consistent with the increased activity of the malic enzyme and the pyruvate carboxylase found in the corresponding PTS mutants. Genetic evidence suggested that such a metabolic effect of PtsN required the transfer of high-energy phosphate through the system. The EIIANtr protein of the PTSNtr thus helps adjust central metabolic fluxes to satisfy the anabolic and energetic demands of the overall cell physiology. This study demonstrates that EIIANtr influences the biochemical reactions that deliver carbon between the upper and lower central metabolic domains for the consumption of sugars by P. putida. These findings indicate that the EIIANtr protein is a key player for orchestrating the fate of carbon in various physiological destinations in this bacterium. Additionally, these results highlight the importance of the posttranslational regulation of extant enzymatic complexes for increasing the robustness of the corresponding metabolic networks.
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Prell J, Mulley G, Haufe F, White JP, Williams A, Karunakaran R, Downie JA, Poole PS. The PTS(Ntr) system globally regulates ATP-dependent transporters in Rhizobium leguminosarum. Mol Microbiol 2012; 84:117-29. [PMID: 22340847 DOI: 10.1111/j.1365-2958.2012.08014.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mutation of ptsP encoding EI(Ntr) of the PTS(Ntr) system in Rhizobium leguminosarum strain Rlv3841 caused a pleiotropic phenotype as observed with many bacteria. The mutant formed dry colonies and grew poorly on organic nitrogen or dicarboxylates. Most strikingly the ptsP mutant had low activity of a broad range of ATP-dependent ABC transporters. This lack of activation, which occurred post-translationally, may explain many of the pleiotropic effects. In contrast proton-coupled transport systems were not inhibited in a ptsP mutant. Regulation by PtsP also involves two copies of ptsN that code for EIIA(Ntr) , resulting in a phosphorylation cascade. As in Escherichia coli, the Rlv3841 PTS(Ntr) system also regulates K(+) homeostasis by transcriptional activation of the high-affinity ATP-dependent K(+) transporter KdpABC. This involves direct interaction of a two-component sensor regulator pair KdpDE with unphosphorylated EIIA(Ntr) . Critically, ptsP mutants, which cannot phosphorylate PtsN1 or PtsN2, had a fully activated KdpABC transporter. This is the opposite pattern from that observed with ABC transporters which apparently require phosphorylation of PtsN. These results suggest that ATP-dependent transport might be regulated via PTS(Ntr) responding to the cellular energy charge. ABC transport may be inactivated at low energy charge, conserving ATP for essential processes including K(+) homeostasis.
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Affiliation(s)
- J Prell
- Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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Chung AL, Jin HL, Huang LJ, Ye HM, Chen JC, Wu Q, Chen GQ. Biosynthesis and characterization of poly(3-hydroxydodecanoate) by β-oxidation inhibited mutant of Pseudomonas entomophila L48. Biomacromolecules 2011; 12:3559-66. [PMID: 21838281 DOI: 10.1021/bm200770m] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A medium-chain-length (MCL) polyhydroxyalkanoates (PHAs) producer Pseudomonas entomophila L48 was investigated for microbial production of 3-hydroxydodecanote homopolymer. Pseudomonas entomophila L48 was found to produce MCL PHA consisting of 3-hydroxyhexanoate (3HHx), 3-hydroxyoctanoate (3HO), 3-hydroxydecanoate (3HD), and 3-hydroxydodecanoate (3HDD) from related carbon sources fatty acids. In this study, some of the genes encoding key enzymes in β-oxidation cycle of P. entomophila such as 3-hydroxyacyl-CoA dehydrogenase, 3-ketoacyl-CoA thiolase, and acetyl-CoA acetyltransferase were deleted to study the relationship between β-oxidation and PHA synthesis in P. entomophila. Among the mutants constructed, P. entomophila LAC26 accumulated over 90 wt % PHA consisting of 99 mol % 3HDD. A fed-batch fermentation process carried out in a 6 L automatic fermentor produced 7.3 g L(-1) PHA consisting of over 97 mol % 3HDD fraction. Properties of MCL PHA were significantly improved along with increasing 3HDD contents. P(2.1 mol % 3HD-co-97.9 mol % 3HDD) produced by P. entomophila LAC25 had the widest temperature range between T(g) and T(m), which were -49.3 and 82.4 °C, respectively, in all MCL PHA reported so far. The new type of PHA also represented high crystallinity caused by side-chain crystallization compared with short side chain PHA. For the first time, P(3HDD) homopolymers were obtained.
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Affiliation(s)
- Ah-Leum Chung
- MOE Key Lab of Protein Sciences, Department of Biological Sciences and Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Kaddor C, Steinbüchel A. Implications of various phosphoenolpyruvate-carbohydrate phosphotransferase system mutations on glycerol utilization and poly(3-hydroxybutyrate) accumulation in Ralstonia eutropha H16. AMB Express 2011; 1:16. [PMID: 21906371 PMCID: PMC3222305 DOI: 10.1186/2191-0855-1-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/13/2011] [Indexed: 11/10/2022] Open
Abstract
The enhanced global biodiesel production is also yielding increased quantities of glycerol as main coproduct. An effective application of glycerol, for example, as low-cost substrate for microbial growth in industrial fermentation processes to specific products will reduce the production costs for biodiesel. Our study focuses on the utilization of glycerol as a cheap carbon source during cultivation of the thermoplastic producing bacterium Ralstonia eutropha H16, and on the investigation of carbohydrate transport proteins involved herein. Seven open reading frames were identified in the genome of strain H16 to encode for putative proteins of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PEP-PTS). Although the core components of PEP-PTS, enzyme I (ptsI) and histidine phosphocarrier protein (ptsH), are available in strain H16, a complete PTS-mediated carbohydrate transport is lacking. Growth experiments employing several PEP-PTS mutants indicate that the putative ptsMHI operon, comprising ptsM (a fructose-specific EIIA component of PTS), ptsH, and ptsI, is responsible for limited cell growth and reduced PHB accumulation (53%, w/w, less PHB than the wild type) of this strain in media containing glycerol as a sole carbon source. Otherwise, the deletion of gene H16_A0384 (ptsN, nitrogen regulatory EIIA component of PTS) seemed to largely compensate the effect of the deleted ptsMHI operon (49%, w/w, PHB). The involvement of the PTS homologous proteins on the utilization of the non-PTS sugar alcohol glycerol and its effect on cell growth as well as PHB and carbon metabolism of R. eutropha will be discussed.
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Kaddor C, Steinbüchel A. Effects of homologous phosphoenolpyruvate-carbohydrate phosphotransferase system proteins on carbohydrate uptake and poly(3-Hydroxybutyrate) accumulation in Ralstonia eutropha H16. Appl Environ Microbiol 2011; 77:3582-90. [PMID: 21478317 PMCID: PMC3127587 DOI: 10.1128/aem.00218-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 03/29/2011] [Indexed: 11/20/2022] Open
Abstract
Seven gene loci encoding putative proteins of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PEP-PTS) were identified in the genome of Ralstonia eutropha H16 by in silico analysis. Except the N-acetylglucosamine-specific PEP-PTS, an additional complete PEP-PTS is lacking in strain H16. Based on these findings, we generated single and multiple deletion mutants defective mainly in the PEP-PTS genes to investigate their influence on carbon source utilization, growth behavior, and poly(3-hydroxybutyrate) (PHB) accumulation. As supposed, the H16 ΔfrcACB and H16 ΔnagFEC mutants exhibited no growth when cultivated on fructose and N-acetylglucosamine, respectively. Furthermore, a transposon mutant with a ptsM-ptsH insertion site did not grow on both carbon sources. The observed phenotype was not complemented, suggesting that it results from an interaction of genes or a polar effect caused by the Tn5::mob insertion. ptsM, ptsH, and ptsI single, double, and triple mutants stored much less PHB than the wild type (about 10 to 39% [wt/wt] of cell dry weight) and caused reduced PHB production in mutants lacking the H16_A2203, H16_A0384, frcACB, or nagFEC genes. In contrast, mutant H16 ΔH16_A0384 accumulated 11.5% (wt/wt) more PHB than the wild type when grown on gluconate and suppressed partially the negative effect of the ptsMHI deletion on PHB synthesis. Based on our experimental data, we discussed whether the PEP-PTS homologous proteins in R. eutropha H16 are exclusively involved in the complex sugar transport system or whether they are also involved in cellular regulatory functions of carbon and PHB metabolism.
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Affiliation(s)
- Chlud Kaddor
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149 Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149 Münster, Germany
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Insight into bacterial phosphotransferase system-mediated signaling by interspecies transplantation of a transcriptional regulator. J Bacteriol 2011; 193:2013-26. [PMID: 21335451 DOI: 10.1128/jb.01459-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial sugar:phosphotransferase system (PTS) delivers phosphoryl groups via proteins EI and HPr to the EII sugar transporters. The antitermination protein LicT controls β-glucoside utilization in Bacillus subtilis and belongs to a family of bacterial transcriptional regulators that are antagonistically controlled by PTS-catalyzed phosphorylations at two homologous PTS regulation domains (PRDs). LicT is inhibited by phosphorylation of PRD1, which is mediated by the β-glucoside transporter EII(Bgl). Phosphorylation of PRD2 is catalyzed by HPr and stimulates LicT activity. Here, we report that LicT, when artificially expressed in the nonrelated bacterium Escherichia coli, is likewise phosphorylated at both PRDs, but the phosphoryl group donors differ. Surprisingly, E. coli HPr phosphorylates PRD1 rather than PRD2, while the stimulatory phosphorylation of PRD2 is carried out by the HPr homolog NPr. This demonstrates that subtle differences in the interaction surface of HPr can switch its affinities toward the PRDs. NPr transfers phosphoryl groups from EI(Ntr) to EIIA(Ntr). Together these proteins form the paralogous PTS(Ntr), which controls the activity of K(+) transporters in response to unknown signals. This is achieved by binding of dephosphorylated EIIA(Ntr) to other proteins. We generated LicT mutants that were controlled either negatively by HPr or positively by NPr and were suitable bio-bricks, in order to monitor or to couple gene expression to the phosphorylation states of these two proteins. With the aid of these tools, we identified the stringent starvation protein SspA as a regulator of EIIA(Ntr) phosphorylation, indicating that PTS(Ntr) represents a stress-related system in E. coli.
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Chavarría M, Santiago C, Platero R, Krell T, Casasnovas JM, de Lorenzo V. Fructose 1-phosphate is the preferred effector of the metabolic regulator Cra of Pseudomonas putida. J Biol Chem 2011; 286:9351-9. [PMID: 21239488 DOI: 10.1074/jbc.m110.187583] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The catabolite repressor/activator (Cra) protein is a global sensor and regulator of carbon fluxes through the central metabolic pathways of gram-negative bacteria. To examine the nature of the effector (or effectors) that signal such fluxes to the protein of Pseudomonas putida, the Cra factor of this soil microorganism has been purified and characterized and its three-dimensional structure determined. Analytical ultracentrifugation, gel filtration, and mobility shift assays showed that the effector-free Cra is a dimer that binds an operator DNA sequence in the promoter region of the fruBKA cluster. Furthermore, fructose 1-phosphate (F1P) was found to most efficiently dissociate the Cra-DNA complex. Thermodynamic parameters of the F1P-Cra-DNA interaction calculated by isothermal titration calorimetry revealed that the factor associates tightly to the DNA sequence 5'-TTAAACGTTTCA-3' (K(D) = 26.3 ± 3.1 nM) and that F1P binds the protein with an apparent stoichiometry of 1.06 ± 0.06 molecules per Cra monomer and a K(D) of 209 ± 20 nM. Other possible effectors, like fructose 1,6-bisphosphate, did not display a significant affinity for the regulator under the assay conditions. Moreover, the structure of Cra and its co-crystal with F1P at a 2-Å resolution revealed that F1P fits optimally the geometry of the effector pocket. Our results thus single out F1P as the preferred metabolic effector of the Cra protein of P. putida.
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Affiliation(s)
- Max Chavarría
- Systems Biology Program, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, 28049 Cantoblanco-Madrid, Spain
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The interplay of the EIIA(Ntr) component of the nitrogen-related phosphotransferase system (PTS(Ntr)) of Pseudomonas putida with pyruvate dehydrogenase. Biochim Biophys Acta Gen Subj 2011; 1810:995-1005. [PMID: 21236318 DOI: 10.1016/j.bbagen.2011.01.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 01/05/2011] [Accepted: 01/06/2011] [Indexed: 11/20/2022]
Abstract
BACKGROUND Pseudomonas putida KT2440 is endowed with a variant of the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS(Ntr)), which is not related to sugar transport but believed to rule the metabolic balance of carbon vs. nitrogen. The metabolic targets of such a system are largely unknown. METHODS Dielectric breakdown of P. putida cells grown in rich medium revealed the presence of forms of the EIIA(Ntr) (PtsN) component of PTS(Ntr), which were strongly associated to other cytoplasmic proteins. To investigate such intracellular partners of EIIA(Ntr), a soluble protein extract of bacteria bearing an E epitope tagged version of PtsN was immunoprecipitated with a monoclonal anti-E antibody and the pulled-down proteins identified by mass spectrometry. RESULTS The E1 subunit of the pyruvate dehydrogenase (PDH) complex, the product of the aceE gene, was identified as a major interaction partner of EIIA(Ntr). To examine the effect of EIIA(Ntr) on PDH, the enzyme activity was measured in extracts of isogenic ptsN(+)/ptsN(-)P. putida strains and the role of phosphorylation was determined. Expression of PtsN and AceE proteins fused to different fluorescent moieties and confocal laser microscopy indicated a significant co-localization of the two proteins in the bacterial cytoplasm. CONCLUSION EIIA(Ntr) down-regulates PDH activity. Both genetic and biochemical evidence revealed that the non-phosphorylated form of PtsN is the protein species that inhibits PDH. GENERAL SIGNIFICANCE EIIA(Ntr) takes part in the node of C metabolism that checks the flux of carbon from carbohydrates into the Krebs cycle by means of direct protein-protein interactions with AceE. This type of control might connect metabolism to many other cellular functions. This article is part of a Special Issue entitled: Systems Biology of Microorganisms.
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Liu Q, Luo G, Zhou XR, Chen GQ. Biosynthesis of poly(3-hydroxydecanoate) and 3-hydroxydodecanoate dominating polyhydroxyalkanoates by β-oxidation pathway inhibited Pseudomonas putida. Metab Eng 2010; 13:11-7. [PMID: 20971206 DOI: 10.1016/j.ymben.2010.10.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/15/2010] [Accepted: 10/18/2010] [Indexed: 10/18/2022]
Abstract
Pseudomonas putida KT2442 produces medium-chain-length polyhydroxyalkanoates consisting of 3-hydroxyhexanoate (3HHx), 3-hydroxyoctanoate (3HO), 3-hydroxydecanoate (3HD), 3-hydroxydodecanoate (3HDD) and 3-hydroxytetradecanoate (3HTD) from relevant fatty acids. P. puitda KT2442 was found to contain key fatty acid degradation enzymes encoded by genes PP2136, PP2137 (fadB and fadA) and PP2214, PP2215 (fadB2x and fadAx), respectively. In this study, the above enzymes and other important fatty acid degradation enzymes, including 3-hydroxyacyl-CoA dehydrogenase and acyl-CoA dehydrogenase encoded by genes PP2047 and PP2048, respectively, were studied for their effects on PHA structures. Mutant P. puitda KTQQ20 was constructed by knocking out the above six genes and also 3-hydroxyacyl-CoA-acyl carrier protein transferase encoded by PhaG, leading to a significant reduction of fatty acid β-oxidation activity. Therefore, P. puitda KTQQ20 synthesized homopolymer poly-3-hydroxydecanoate (PHD) or P(3HD-co-84mol% 3HDD), when grown on decanoic acid or dodecanoic acid. Melting temperatures of PHD and P(3HD-co-84mol% 3HDD) were 72 and 78 °C, respectively. Thermal and mechanical properties of PHD and P(3HD-co-84mol% 3HDD) were much better as compared with an mcl-PHA, consisting of lower content of C10 or C12 monomers. For the first time, it was shown that homopolymer PHD and 3HDD monomers dominating PHA could be synthesized by β-oxidation inhibiting P. putida grown on relevant carbon sources.
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Affiliation(s)
- Qian Liu
- Multidisciplinary Research Center, Shantou University, Shantou 515063, Guangdong, China
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