1
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Jakowec NA, Finegan M, Finkel SE. Disruption of trehalose periplasmic recycling dysregulates cAMP-CRP signaling in Escherichia coli during stationary phase. J Bacteriol 2023; 205:e0029223. [PMID: 37916804 PMCID: PMC10662143 DOI: 10.1128/jb.00292-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/13/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Survival during starvation hinges on the ability to manage intracellular energy reserves and to initiate appropriate metabolic responses to perturbations of such reserves. How Escherichia coli manage carbon storage systems under starvation stress, as well as transpose changes in intracellular metabolite levels into regulatory signals, is not well understood. Endogenous trehalose metabolism may be at the center of these processes, coupling carbon storage with carbon starvation responses. The coupled transport to the periplasm and subsequent hydrolysis of trehalose back to glucose for transport to the cytoplasm may function as a crucial metabolic signaling pathway. Although trehalose has been characterized as a stress protectant in E. coli, the disaccharide also functions as both an energy storage compound and a regulator of carbohydrate metabolism in fungi, plants, and other bacteria. Our research explores the metabolic regulatory properties of trehalose in E. coli and a potential mechanism by which the intracellular carbon pool is interconnected with regulatory circuits, enabling long-term survival.
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Affiliation(s)
- Nicolaus A. Jakowec
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Melissa Finegan
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Steven E. Finkel
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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2
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Urs K, Zimmern PE, Reitzer L. Control of glnA (glutamine synthetase) expression by urea in non-pathogenic and uropathogenic Escherichia coli. J Bacteriol 2023; 205:e0026823. [PMID: 37902379 PMCID: PMC10662117 DOI: 10.1128/jb.00268-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
IMPORTANCE The bacteria that cause urinary tract infections often become resistant to antibiotic treatment, and genes expressed during an infection could suggest non-antibiotic targets. During growth in urine, glnA (specifying glutamine synthetase) expression is high, but our results show that urea induces glnA expression independent of the regulation that responds to nitrogen limitation. Although our results suggest that glnA is an unlikely target for therapy because of variation in urinary components between individuals, our analysis of glnA expression in urine-like environments has revealed previously undescribed layers of regulation. In other words, regulatory mechanisms that are discovered in a laboratory environment do not necessarily operate in the same way in nature.
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Affiliation(s)
- Karthik Urs
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Philippe E. Zimmern
- Department of Urology, University of Texas Southwestern Medical School, Dallas, Texas, USA
| | - Larry Reitzer
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
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3
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Tang Y, Qin D, Tian Z, Chen W, Ma Y, Wang J, Yang J, Yan D, Dixon R, Wang YP. Diurnal switches in diazotrophic lifestyle increase nitrogen contribution to cereals. Nat Commun 2023; 14:7516. [PMID: 37980355 PMCID: PMC10657418 DOI: 10.1038/s41467-023-43370-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/07/2023] [Indexed: 11/20/2023] Open
Abstract
Uncoupling of biological nitrogen fixation from ammonia assimilation is a prerequisite step for engineering ammonia excretion and improvement of plant-associative nitrogen fixation. In this study, we have identified an amino acid substitution in glutamine synthetase, which provides temperature sensitive biosynthesis of glutamine, the intracellular metabolic signal of the nitrogen status. As a consequence, negative feedback regulation of genes and enzymes subject to nitrogen regulation, including nitrogenase is thermally controlled, enabling ammonia excretion in engineered Escherichia coli and the plant-associated diazotroph Klebsiella oxytoca at 23 °C, but not at 30 °C. We demonstrate that this temperature profile can be exploited to provide diurnal oscillation of ammonia excretion when variant bacteria are used to inoculate cereal crops. We provide evidence that diurnal temperature variation improves nitrogen donation to the plant because the inoculant bacteria have the ability to recover and proliferate at higher temperatures during the daytime.
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Affiliation(s)
- Yuqian Tang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Debin Qin
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Zhexian Tian
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Wenxi Chen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Yuanxi Ma
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jilong Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Jianguo Yang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Dalai Yan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences & School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China.
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4
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Sun Y, Zhang Y, Zhao T, Luan Y, Wang Y, Yang C, Shen B, Huang X, Li G, Zhao S, Zhao G, Wang Q. Acetylation coordinates the crosstalk between carbon metabolism and ammonium assimilation in Salmonella enterica. EMBO J 2023; 42:e112333. [PMID: 37183585 PMCID: PMC10308350 DOI: 10.15252/embj.2022112333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/21/2023] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Enteric bacteria use up to 15% of their cellular energy for ammonium assimilation via glutamine synthetase (GS)/glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) in response to varying ammonium availability. However, the sensory mechanisms for effective and appropriate coordination between carbon metabolism and ammonium assimilation have not been fully elucidated. Here, we report that in Salmonella enterica, carbon metabolism coordinates the activities of GS/GDH via functionally reversible protein lysine acetylation. Glucose promotes Pat acetyltransferase-mediated acetylation and activation of adenylylated GS. Simultaneously, glucose induces GDH acetylation to inactivate the enzyme by impeding its catalytic centre, which is reversed upon GDH deacetylation by deacetylase CobB. Molecular dynamics (MD) simulations indicate that adenylylation is required for acetylation-dependent activation of GS. We show that acetylation and deacetylation occur within minutes of "glucose shock" to promptly adapt to ammonium/carbon variation and finely balance glutamine/glutamate synthesis. Finally, in a mouse infection model, reduced S. enterica growth caused by the expression of adenylylation-mimetic GS is rescued by acetylation-mimicking mutations. Thus, glucose-driven acetylation integrates signals from ammonium assimilation and carbon metabolism to fine-tune bacterial growth control.
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Affiliation(s)
- Yunwei Sun
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yuebin Zhang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Tingting Zhao
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi Luan
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
| | - Ying Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Chen Yang
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Bo Shen
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xi Huang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Shimin Zhao
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Collaborative Innovation Center for Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Guo‐ping Zhao
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Shanghai‐MOST Key Laboratory of Disease and Health GenomicsChinese National Human Genome Center at ShanghaiShanghaiChina
- Department of Microbiology and Li KaShing Institute of Health SciencesThe Chinese University of Hong Kong, Prince of Wales HospitalShatin, New Territories, Hong Kong SARChina
| | - Qijun Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
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5
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Meng F, Lyu Y, Chen X, Lu F, Zhao H, Lu Y, Zhao M, Lu Z. Maltose-Enhanced Exopolysaccharide Synthesis of Lactiplantibacillus plantarum through CRP-like Protein. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:1113-1121. [PMID: 36602107 DOI: 10.1021/acs.jafc.2c07880] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Carbon sources alter the synthesis of exopolysaccharides (EPS) in Lactiplantibacillus plantarum. Maltose increased the EPS production of L. plantarum 163 6.5-fold. Subsequently, EPS production, transcriptome, and proteome were analyzed using glucose or maltose to further clarify the regulatory mechanism. A cAMP receptor protein (UniProtKB: F9UNI5) has been identified to control EPS synthesis in the presence of cAMP by binding to the EPS synthesis promoter Pcps4A-J. Overexpression of the cAMP synthesis gene cyaA increased cAMP content and EPS production 4.5- and 2.2-fold, respectively. Furthermore, yogurt produced with L. plantarum 163-cyaA had a similar viscosity to that of commercial Greek yogurt; it had 20 and 83.7% greater viscosity than that produced with L. plantarum 163 with maltose and glucose, respectively. These findings indicated that L. plantarum 163-cyaA has potential applications in the production of functional fermented dairy products.
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Affiliation(s)
- Fanqiang Meng
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture; Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Nanjing 210095, China
| | - Yunbin Lyu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
| | - Xiaoyu Chen
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
| | - Fengxia Lu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
| | - Haizhen Zhao
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
| | - Yingjian Lu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 21003, China
| | - Mingwen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture; Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, Nanjing 210095, China
| | - Zhaoxin Lu
- College of Food Science and Technology, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China
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6
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Paquette AR, Payne SR, McKay GA, Brazeau-Henrie JT, Darnowski MG, Kammili A, Bernal F, Mah TF, Gruenheid S, Nguyen D, Boddy CN. RpoN-Based stapled peptides with improved DNA binding suppress Pseudomonas aeruginosa virulence. RSC Med Chem 2022; 13:445-455. [PMID: 35647551 PMCID: PMC9020619 DOI: 10.1039/d1md00371b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/02/2022] [Indexed: 11/21/2022] Open
Abstract
Stapled peptides have the ability to mimic α-helices involved in protein binding and have proved to be effective pharmacological agents for disrupting protein-protein interactions. DNA-binding proteins such as transcription factors bind their cognate DNA sequences via an α-helix interacting with the major groove of DNA. We previously developed a stapled peptide based on the bacterial alternative sigma factor RpoN capable of binding the RpoN DNA promoter sequence and inhibiting RpoN-mediated expression in Escherichia coli. We have elucidated a structure-activity relationship for DNA binding by this stapled peptide, improving DNA binding affinity constants in the high nM range. Lead peptides were shown to have low toxicity as determined by their low hemolytic activity at 100 μM and were shown to have anti-virulence activity in a Galleria mellonella model of Pseudomonas aeruginosa infection. These findings support further preclinical development of stapled peptides as antivirulence agents targeting P. aeruginosa.
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Affiliation(s)
- André R. Paquette
- Department of Chemistry and Biomolecular Sciences, University of OttawaOttawaONK1N 6N5 Canada
| | - Sterling R. Payne
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, National Institutes of HealthFrederickMD 21702USA
| | - Geoffrey A. McKay
- Meakins-Christie Laboratories, Research Institute of the McGill University Health CentreMontrealQuebec H4A 3J1Canada
| | | | - Micheal G. Darnowski
- Department of Chemistry and Biomolecular Sciences, University of OttawaOttawaONK1N 6N5 Canada
| | - Anitha Kammili
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa ON K1N 6N5 Canada
| | - Federico Bernal
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, National Institutes of HealthFrederickMD 21702USA
| | - Thien-Fah Mah
- Department of Biochemistry, Microbiology, and Immunology, University of OttawaOttawaONK1H 8M5Canada
| | | | - Dao Nguyen
- Meakins-Christie Laboratories, Research Institute of the McGill University Health CentreMontrealQuebec H4A 3J1Canada,Department of Medicine, McGill UniversityMontrealQuebec H4A 3J1Canada
| | - Christopher N. Boddy
- Department of Chemistry and Biomolecular Sciences, University of OttawaOttawaONK1N 6N5 Canada
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7
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Transition of Dephospho-DctD to the Transcriptionally Active State via Interaction with Dephospho-IIA
Glc. mBio 2022; 13:e0383921. [PMID: 35311533 PMCID: PMC9040800 DOI: 10.1128/mbio.03839-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Exopolysaccharides (EPSs), biofilm-maturing components of Vibrio vulnificus, are abundantly produced when the expression of two major EPS gene clusters is activated by an enhancer-binding transcription factor, DctD2, whose expression and phosphorylation are induced by dicarboxylic acids. Surprisingly, when glucose was supplied to V. vulnificus, similar levels of expression of these clusters occurred, even in the absence of dicarboxylic acids. This glucose-dependent activation was also mediated by DctD2, whose expression was sequentially activated by the transcription regulator NtrC. Most DctD2 in cells grown without dicarboxylic acids was present in a dephosphorylated state, known as the transcriptionally inactive form. However, in the presence of glucose, a dephosphorylated component of the glucose-specific phosphotransferase system, d-IIAGlc, interacted with dephosphorylated DctD2 (d-DctD2). While d-DctD2 did not show any affinity to a DNA fragment containing the DctD-binding sequences, the complex of d-DctD2 and d-IIAGlc exhibited specific and efficient DNA binding, similar to the phosphorylated DctD2. The d-DctD2-mediated activation of the EPS gene clusters’ expression was not fully achieved in cells grown with mannose. Furthermore, the degrees of expression of the clusters under glycerol were less than those under mannose. This was caused by an antagonistic and competitive effect of GlpK, whose expression was increased by glycerol, in forming a complex with d-DctD2 by d-IIAGlc. The data demonstrate a novel regulatory pathway for V. vulnificus EPS biosynthesis and biofilm maturation in the presence of glucose, which is mediated by d-DctD2 through its transition to the transcriptionally active state by interacting with available d-IIAGlc.
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8
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Pal A, Iyer MS, Srinivasan S, Narain Seshasayee AS, Venkatesh KV. Global pleiotropic effects in adaptively evolved Escherichia coli lacking CRP reveal molecular mechanisms that define the growth physiology. Open Biol 2022; 12:210206. [PMID: 35167766 PMCID: PMC8846999 DOI: 10.1098/rsob.210206] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Evolution facilitates emergence of fitter phenotypes by efficient allocation of cellular resources in conjunction with beneficial mutations. However, system-wide pleiotropic effects that redress the perturbations to the apex node of the transcriptional regulatory networks remain unclear. Here, we elucidate that absence of global transcriptional regulator CRP in Escherichia coli results in alterations in key metabolic pathways under glucose respiratory conditions, favouring stress- or hedging-related functions over growth-enhancing functions. Further, we disentangle the growth-mediated effects from the CRP regulation-specific effects on these metabolic pathways. We quantitatively illustrate that the loss of CRP perturbs proteome efficiency, as evident from metabolic as well as ribosomal proteome fractions, that corroborated with intracellular metabolite profiles. To address how E. coli copes with such systemic defect, we evolved Δcrp mutant in the presence of glucose. Besides acquiring mutations in the promoter of glucose transporter ptsG, the evolved populations recovered the metabolic pathways to their pre-perturbed state coupled with metabolite re-adjustments, which altogether enabled increased growth. By contrast to Δcrp mutant, the evolved strains remodelled their proteome efficiency towards biomass synthesis, albeit at the expense of carbon efficiency. Overall, we comprehensively illustrate the genetic and metabolic basis of pleiotropic effects, fundamental for understanding the growth physiology.
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Affiliation(s)
- Ankita Pal
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Mahesh S. Iyer
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sumana Srinivasan
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - K. V. Venkatesh
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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9
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Efficient ammonia production from food by-products by engineered Escherichia coli. AMB Express 2020; 10:150. [PMID: 32809073 PMCID: PMC7434829 DOI: 10.1186/s13568-020-01083-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 08/08/2020] [Indexed: 12/22/2022] Open
Abstract
Ammonia is used as a fertilizer for agriculture, chemical raw material, and carrier for transporting hydrogen, and with economic development, the demand for ammonia has increased. The Haber-Bosch process, which is the main method for producing ammonia, can produce ammonia with high efficiency. However, since it consumes a large amount of fossil energy, it is necessary to develop an alternative method for producing ammonia with less environmental impact. Ammonia production from food by-products is an appealing production process owing to unused resource usage, including waste, and mild reaction conditions. However, when food by-products and biomass are used as feedstocks, impurities often reduce productivity. Using metabolic profiling, glucose was identified as a potential inhibitor of ammonia production from impure food by-products. We constructed the recombinant Escherichia coli, in which glucose uptake was reduced by ptsG gene disruption and amino acid catabolism was promoted by glnA gene disruption. Ammonia production efficiency from okara, a food by-product, was improved in this strain; 35.4 mM ammonia was produced (47% yield). This study might provide a strategy for efficient ammonia production from food by-products.
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10
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Abstract
The metabolite 2-oxoglutarate (also known as α-ketoglutarate, 2-ketoglutaric acid, or oxoglutaric acid) lies at the intersection between the carbon and nitrogen metabolic pathways. This compound is a key intermediate of one of the most fundamental biochemical pathways in carbon metabolism, the tricarboxylic acid (TCA) cycle. In addition, 2-oxoglutarate also acts as the major carbon skeleton for nitrogen-assimilatory reactions. Experimental data support the conclusion that intracellular levels of 2-oxoglutarate fluctuate according to nitrogen and carbon availability. This review summarizes how nature has capitalized on the ability of 2-oxoglutarate to reflect cellular nutritional status through evolution of a variety of 2-oxoglutarate-sensing regulatory proteins. The number of metabolic pathways known to be regulated by 2-oxoglutarate levels has increased significantly in recent years. The signaling properties of 2-oxoglutarate are highlighted by the fact that this metabolite regulates the synthesis of the well-established master signaling molecule, cyclic AMP (cAMP), in Escherichia coli.
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11
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Zhang YT, Jiang F, Tian ZX, Huo YX, Sun YC, Wang YP. CRP-cyclic AMP dependent inhibition of the xylene-responsive σ(54)-promoter Pu in Escherichia coli. PLoS One 2014; 9:e86727. [PMID: 24466213 PMCID: PMC3900584 DOI: 10.1371/journal.pone.0086727] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2013] [Indexed: 11/18/2022] Open
Abstract
The expression of σ(54)-dependent Pseudomonas putida Pu promoter is activated by XylR activator when cells are exposed to a variety of aromatic inducers. In this study, the transcriptional activation of the P. putida Pu promoter was recreated in the heterologous host Escherichia coli. Here we show that the cAMP receptor protein (CRP), a well-known carbon utilization regulator, had an inhibitory effect on the expression of Pu promoter in a cAMP-dependent manner. The inhibitory effect was not activator specific. In vivo KMnO4 and DMS footprinting analysis indicated that CRP-cAMP poised the RNA polymerase at Pu promoter, inhibiting the isomerization step of the transcription initiation even in the presence of an activator. Therefore, the presence of PTS-sugar, which eliminates cAMP, could activate the poised RNA polymerase at Pu promoter to transcribe. Moreover, the activation region 1 (AR1) of CRP, which interacts directly with the αCTD (C-terminal domain of α-subunit) of RNA polymerase, was found essential for the CRP-mediated inhibition at Pu promoter. A model for the above observations is discussed.
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Affiliation(s)
- Yuan-Tao Zhang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Feng Jiang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhe-Xian Tian
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Yi-Xin Huo
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Yi-Cheng Sun
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
- * E-mail:
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12
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van Heeswijk WC, Westerhoff HV, Boogerd FC. Nitrogen assimilation in Escherichia coli: putting molecular data into a systems perspective. Microbiol Mol Biol Rev 2013; 77:628-95. [PMID: 24296575 PMCID: PMC3973380 DOI: 10.1128/mmbr.00025-13] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We present a comprehensive overview of the hierarchical network of intracellular processes revolving around central nitrogen metabolism in Escherichia coli. The hierarchy intertwines transport, metabolism, signaling leading to posttranslational modification, and transcription. The protein components of the network include an ammonium transporter (AmtB), a glutamine transporter (GlnHPQ), two ammonium assimilation pathways (glutamine synthetase [GS]-glutamate synthase [glutamine 2-oxoglutarate amidotransferase {GOGAT}] and glutamate dehydrogenase [GDH]), the two bifunctional enzymes adenylyl transferase/adenylyl-removing enzyme (ATase) and uridylyl transferase/uridylyl-removing enzyme (UTase), the two trimeric signal transduction proteins (GlnB and GlnK), the two-component regulatory system composed of the histidine protein kinase nitrogen regulator II (NRII) and the response nitrogen regulator I (NRI), three global transcriptional regulators called nitrogen assimilation control (Nac) protein, leucine-responsive regulatory protein (Lrp), and cyclic AMP (cAMP) receptor protein (Crp), the glutaminases, and the nitrogen-phosphotransferase system. First, the structural and molecular knowledge on these proteins is reviewed. Thereafter, the activities of the components as they engage together in transport, metabolism, signal transduction, and transcription and their regulation are discussed. Next, old and new molecular data and physiological data are put into a common perspective on integral cellular functioning, especially with the aim of resolving counterintuitive or paradoxical processes featured in nitrogen assimilation. Finally, we articulate what still remains to be discovered and what general lessons can be learned from the vast amounts of data that are available now.
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13
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Li Z, Zhang W, Wang Y. Upstream CRP-binding site is not essential for CRP-cAMP-mediated inhibition on the nifU promoter. Sci Bull (Beijing) 2013. [DOI: 10.1007/bf03183850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Jiang F, Tian Z, Wang Y. Characterization of ligand response properties of the CRP protein from Pseudomonas putida. CHINESE SCIENCE BULLETIN-CHINESE 2012. [DOI: 10.1007/s11434-012-5360-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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PHB Biosynthesis in Catabolite Repression Mutant of Burkholderia sacchari. Curr Microbiol 2011; 63:319-26. [DOI: 10.1007/s00284-011-9981-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/05/2011] [Indexed: 11/24/2022]
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16
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Narang A. Quantitative effect and regulatory function of cyclic adenosine 5'-phosphate in Escherichia coli. J Biosci 2009; 34:445-63. [PMID: 19805906 DOI: 10.1007/s12038-009-0051-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Cyclic adenosine 5'-phosphate (cAMP) is a global regulator of gene expression in Escherichia coli. Despite decades of intensive study, the quantitative effect and regulatory function of cAMP remain the subjects of considerable debate. Here, we analyse the data in the literature to show that: (a) In carbon-limited cultures (including cultures limited by glucose), cAMP is at near-saturation levels with respect to expression of several catabolic promoters (including lac, ara and gal). It follows that cAMP receptor protein (CRP) cAMP-mediated regulation cannot account for the strong repression of these operons in the presence of glucose. (b) The cAMP levels in carbon-excess cultures are substantially lower than those observed in carbon-limited cultures under these conditions, the expression of catabolic promoters is very sensitive to variation of cAMP levels. (c)=CRPcAMP invariably activates the expression of catabolic promoters, but it appears to inhibit the expression of anabolic promoters. (d) These results suggest that the physiological function of cAMP is to maintain homeostatic energy levels. In carbon-limited cultures, growth is limited by the supply of energy; the cAMP levels therefore increase to enhance energy accumulation by activating the catabolic promoters and inhibiting the anabolic promoters. Conversely, in carbonexcess cultures, characterized by the availability of excess energy, the cAMP levels decrease in order to depress energy accumulation by inhibiting the catabolic promoters and activating the anabolic promoters.
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Affiliation(s)
- Atul Narang
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India.
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The Crp-activated small noncoding regulatory RNA CyaR (RyeE) links nutritional status to group behavior. J Bacteriol 2008; 191:461-76. [PMID: 18978044 DOI: 10.1128/jb.01157-08] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small noncoding regulatory RNAs (sRNAs) play a key role in regulating the expression of many genes in Escherichia coli and other bacteria. Many of the sRNAs identified in E. coli bind to mRNAs in an Hfq-dependent manner and stimulate or inhibit translation of the mRNAs. Several sRNAs are regulated by well-studied global regulators. Here, we report characterization of the CyaR (RyeE) sRNA, which was previously identified in a global search for sRNAs in E. coli. We demonstrated that CyaR is positively regulated by the global regulator Crp under conditions in which cyclic AMP levels are high. We showed by using microarray analysis and Northern blotting that several genes are negatively regulated by CyaR, including ompX, encoding a major outer membrane protein; luxS, encoding the autoinducer-2 synthase; nadE, encoding an essential NAD synthetase; and yqaE, encoding a predicted membrane protein with an unknown function. Using translational lacZ fusions to yqaE, ompX, nadE, and luxS, we demonstrated that the negative regulation of these genes by CyaR occurs at the posttranscriptional level and is direct. Different portions of a highly conserved 3' region of CyaR are predicted to pair with sequences near the ribosome binding site of each of these targets; mutations in this sequence affected regulation, and compensatory mutations in the target mRNA restored regulation, confirming that there is direct regulation by the sRNA. These results provide insight into the mechanisms by which Crp negatively regulates genes such as luxS and ompX and provide a link between catabolite repression, quorum sensing, and nitrogen assimilation in E. coli.
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Dual involvement of CbrAB and NtrBC in the regulation of histidine utilization in Pseudomonas fluorescens SBW25. Genetics 2008; 178:185-95. [PMID: 18202367 DOI: 10.1534/genetics.107.081984] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas fluorescens SBW25 is capable of growing on histidine as a sole source of carbon and/or nitrogen. Previous work showed that the two-component regulatory system CbrAB is required for expression of the histidine utilization (hut) locus when histidine is the sole source of carbon and nitrogen. Here, using mutational analysis and transcriptional assays, we demonstrate involvement of a second two-component system, NtrBC. When histidine is the sole carbon source, transcription of the hutU operon is initiated from a sigma54-type promoter and requires CbrB (an enhancer binding protein for sigma54-recruitment). However, when histidine is the sole nitrogen source, the hutU operon is transcribed from a sigma70-type promoter and requires either CbrB or the nitrogen regulator, NtrC. No role was found for the SBW25 homolog of the nitrogen assimilation control protein (NAC). Biolog phenotypic microarray analysis of the ability of the three mutants (DeltacbrB, DeltantrC, and DeltacbrB DeltantrC) to utilize 190 carbon and 95 nitrogen substrates confirmed the central regulatory roles of CbrAB and NtrBC in cellular carbon and nitrogen catabolism: deletion of cbrB abolished growth on 20 carbon substrates; deletion of ntrC eliminated growth on 28 nitrogen substrates. A double cbrB-ntrC mutant was unable to utilize a further 14 nitrogen substrates (including histidine, proline, leucine, isoleucine, and valine). Our data show that CbrAB plays a role in regulation of both carbon and nitrogen catabolism and maintains activity of catabolic pathways under different C:N ratios.
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Porrúa O, García-Jaramillo M, Santero E, Govantes F. The LysR-type regulator AtzR binding site: DNA sequences involved in activation, repression and cyanuric acid-dependent repositioning. Mol Microbiol 2007; 66:410-27. [PMID: 17854404 DOI: 10.1111/j.1365-2958.2007.05927.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The LysR-type transcriptional regulator (LTTR) AtzR of Pseudomonas sp. strain ADP activates the cyanuric acid-utilization atzDEF operon in response to low nitrogen availability and the presence of cyanuric acid. AtzR also represses expression of its own gene, atzR, transcribed divergently from atzDEF. Here we identify and functionally characterize the cis-acting sequences at the atzR-atzDEF divergent promoter region required for AtzR-dependent regulation. AtzR binds a single site overlapping both the PatzR and PatzDEF promoters and induces a DNA bend immediately upstream from PatzDEF. Interaction of AtzR with the inducer cyanuric acid shortens the protein-DNA interaction region and relaxes the DNA bend. The AtzR binding site contains a strong binding determinant, the repression binding site (RBS), centred at position -65 relative to the atzDEF transcriptional start, containing the LTTR binding consensus motif. Integrity of the RBS is essential for high-affinity AtzR binding, activation and autorepression. A second, weaker binding determinant, the activation binding site (ABS), is present between the RBS and PatzDEF. Deletion of the ABS only provokes a modest decrease in AtzR affinity for the promoter region in vitro, but abolishes repression of PatzR in vivo. Involvement of the ABS in autorepression has not been previously reported.
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Affiliation(s)
- Odil Porrúa
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC, and Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide
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20
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Liang W, Pascual-Montano A, Silva AJ, Benitez JA. The cyclic AMP receptor protein modulates quorum sensing, motility and multiple genes that affect intestinal colonization in Vibrio cholerae. Microbiology (Reading) 2007; 153:2964-2975. [PMID: 17768239 DOI: 10.1099/mic.0.2007/006668-0] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae is the causative agent of cholera, which continues to be a major public health concern in Asia, Africa and Latin America. The bacterium can persist outside the human host and alternates between planktonic and biofilm community lifestyles. Transition between the different lifestyles is mediated by multiple signal transduction pathways including quorum sensing. Expression of the Zn-metalloprotease haemagglutinin (HA)/protease is subject to a dual regulation which involves the quorum-sensing regulator HapR and the cAMP receptor protein. In a previous study, we observed that a mutant defective in the cAMP-receptor protein (CRP) expressed lower levels of HapR. To further investigate the role of CRP in modulating HapR and other signal transduction pathways, we performed global gene expression profiling of a Deltacrp mutant of El Tor biotype V. cholerae. Here we show that CRP is required for the biosynthesis of cholera autoinducer 1 (CAI-1) and affects the expression of multiple HapR-regulated genes. As expected, the Deltacrp mutant produced more cholera toxin and enhanced biofilm. Expression of flagellar genes, reported to be affected in DeltahapR mutants, was diminished in the Deltacrp mutant. However, an epistasis analysis indicated that cAMP-CRP affects motility by a mechanism independent of HapR. Inactivation of crp inhibited the expression of multiple genes reported to be strongly induced in vivo and to affect the ability of V. cholerae to colonize the small intestine and cause disease. These genes included ompU, ompT and ompW encoding outer-membrane proteins, the alternative sigma factor sigma(E) required for intestinal colonization, and genes involved in anaerobic energy metabolism. Our results indicate that CRP plays a crucial role in the V. cholerae life cycle by affecting quorum sensing and multiple genes required for survival of V. cholerae in the human host and the environment.
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Affiliation(s)
- Weili Liang
- Morehouse School of Medicine, Department of Microbiology, Biochemistry and Immunology, 720 Westview Dr. SW, Atlanta, GA, USA
| | - Alberto Pascual-Montano
- Computer Architecture Department, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Anisia J Silva
- Morehouse School of Medicine, Department of Microbiology, Biochemistry and Immunology, 720 Westview Dr. SW, Atlanta, GA, USA
| | - Jorge A Benitez
- Morehouse School of Medicine, Department of Microbiology, Biochemistry and Immunology, 720 Westview Dr. SW, Atlanta, GA, USA
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Schwab S, Souza EM, Yates MG, Persuhn DC, Steffens MBR, Chubatsu LS, Pedrosa FO, Rigo LU. The glnAntrBC operon of Herbaspirillum seropedicae is transcribed by two oppositely regulated promoters upstream of glnA. Can J Microbiol 2007; 53:100-5. [PMID: 17496955 DOI: 10.1139/w06-113] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Herbaspirillum seropedicae is an endophytic bacterium that fixes nitrogen under microaerophilic conditions. The putative promoter sequences glnAp1 (sigma70-dependent) and glnAp2 (sigma54), and two NtrC-binding sites were identified upstream from the glnA, ntrB and ntrC genes of this microorganism. To study their transcriptional regulation, we used lacZ fusions to the H. seropedicae glnA gene, and the glnA-ntrB and ntrB-ntrC intergenic regions. Expression of glnA was up-regulated under low ammonium, but no transcription activity was detected from the intergenic regions under any condition tested, suggesting that glnA, ntrB and ntrC are co-transcribed from the promoters upstream of glnA. Ammonium regulation was lost in the ntrC mutant strain. A point mutation was introduced in the conserved -25/-24 dinucleotide (GG-->TT) of the putative sigma54-dependent promoter (glnAp2). Contrary to the wild-type promoter, glnA expression with the mutant glnAp2 promoter was repressed in the wild-type strain under low ammonium levels, but this repression was abolished in an ntrC background. Together our results indicate that the H. seropedicae glnAntrBC operon is regulated from two functional promoters upstream from glnA, which are oppositely regulated by the NtrC protein.
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Affiliation(s)
- Stefan Schwab
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
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Mao XJ, Huo YX, Buck M, Kolb A, Wang YP. Interplay between CRP-cAMP and PII-Ntr systems forms novel regulatory network between carbon metabolism and nitrogen assimilation in Escherichia coli. Nucleic Acids Res 2007; 35:1432-40. [PMID: 17284458 PMCID: PMC1865078 DOI: 10.1093/nar/gkl1142] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, utilization of carbon sources is regulated by the phosphoenolpyruvate-dependent phosphotransferase system (PTS), which modulates the intracellular levels of cAMP. The cAMP receptor protein (CRP) controls the transcription of many catabolic genes. The availability of nitrogen is sensed by the PII protein at the level of intracellular glutamine. Glutamine is transported mainly by GlnHPQ, and synthesized by glutamine synthetase (GS) encoded by glnA. Previous studies suggest that CRP affects nitrogen assimilation. Here we showed that at least two mechanisms are involved. First, CRP activates glnHp1 via synergistic binding with sigma 70 RNA polymerase (Eσ70) and represses glnHp2. As a consequence, in the presence of glutamine, the overall enhancement of glnHPQ expression alters GlnB signalling and de-activates glnAp2. Second, in vitro studies show that CRP can be recruited by sigma 54 holoenzyme (Eσ54) to a site centred at −51.5 upstream of glnAp2. CRP-induced DNA-bending prevents the nitrogen regulation protein C (NtrC) activator from approaching the activator-accessible face of the promoter-bound Eσ54 closed complex, and inhibits glnAp2. Therefore, as the major transcriptional effector of the ‘glucose effect’, CRP affects both the signal transduction pathway and the overall geometry of the transcriptional machinery of components of the nitrogen regulon.
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Affiliation(s)
- Xian-Jun Mao
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China, Department of Biological Science, Imperial College of Science, Technology and Medicine, London SW72AZ, UK and Unité des Régulations Transcriptionnelles, URA-CNRS 2172, Institut Pasteur, 75724 Paris, France
| | - Yi-Xin Huo
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China, Department of Biological Science, Imperial College of Science, Technology and Medicine, London SW72AZ, UK and Unité des Régulations Transcriptionnelles, URA-CNRS 2172, Institut Pasteur, 75724 Paris, France
| | - Martin Buck
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China, Department of Biological Science, Imperial College of Science, Technology and Medicine, London SW72AZ, UK and Unité des Régulations Transcriptionnelles, URA-CNRS 2172, Institut Pasteur, 75724 Paris, France
| | - Annie Kolb
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China, Department of Biological Science, Imperial College of Science, Technology and Medicine, London SW72AZ, UK and Unité des Régulations Transcriptionnelles, URA-CNRS 2172, Institut Pasteur, 75724 Paris, France
| | - Yi-Ping Wang
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, P. R. China, Department of Biological Science, Imperial College of Science, Technology and Medicine, London SW72AZ, UK and Unité des Régulations Transcriptionnelles, URA-CNRS 2172, Institut Pasteur, 75724 Paris, France
- *To whom correspondence should be addressed. +86 10 6275 8490+86 10 6275 6325
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Integration of regulatory signals through involvement of multiple global regulators: control of the Escherichia coli gltBDF operon by Lrp, IHF, Crp, and ArgR. BMC Microbiol 2007; 7:2. [PMID: 17233899 PMCID: PMC1784095 DOI: 10.1186/1471-2180-7-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 01/18/2007] [Indexed: 11/10/2022] Open
Abstract
Background The glutamate synthase operon (gltBDF) contributes to one of the two main pathways of ammonia assimilation in Escherichia coli. Of the seven most-global regulators, together affecting expression of about half of all E. coli genes, two were previously shown to exert direct, positive control on gltBDF transcription: Lrp and IHF. The involvement of Lrp is unusual in two respects: first, it is insensitive to the usual coregulator leucine, and second, Lrp binds more than 150 bp upstream of the transcription starting point. There was indirect evidence for involvement of a third global regulator, Crp. Given the physiological importance of gltBDF, and the potential opportunity to learn about integration of global regulatory signals, a combination of in vivo and in vitro approaches was used to investigate the involvement of additional regulatory proteins, and to determine their relative binding positions and potential interactions with one another and with RNA polymerase (RNAP). Results Crp and a more local regulator, ArgR, directly control gltBDF transcription, both acting negatively. Crp-cAMP binds a sequence centered at -65.5 relative to the transcript start. Mutation of conserved nucleotides in the Crp binding site abolishes the Crp-dependent repression. ArgR also binds to the gltBDF promoter region, upstream of the Lrp binding sites, and decreases transcription. RNAP only yields a defined DNAse I footprint under two tested conditions: in the presence of both Lrp and IHF, or in the presence of Crp-cAMP. The DNAse I footprint of RNAP in the presence of Lrp and IHF is altered by ArgR. Conclusion The involvement of nearly half of E. coli's most-global regulatory proteins in the control of gltBDF transcription is striking, but seems consistent with the central metabolic role of this operon. Determining the mechanisms of activation and repression for gltBDF was beyond the scope of this study. However the results are consistent with a model in which IHF bends the DNA to allow stabilizing contacts between Lrp and RNAP, ArgR interferes with such contacts, and Crp introduces an interfering bend in the DNA and/or stabilizes RNAP in a poised but inactive state.
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Tian Z, Mao X, Su W, Li J, Becker A, Wang Y. Exogenous cAMP upregulates the expression of glnII and glnK-amtB genes in Sinorhizobium meliloti 1021. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/s11434-006-2079-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Huo YX, Tian ZX, Rappas M, Wen J, Chen YC, You CH, Zhang X, Buck M, Wang YP, Kolb A. Protein-induced DNA bending clarifies the architectural organization of the sigma54-dependent glnAp2 promoter. Mol Microbiol 2006; 59:168-80. [PMID: 16359326 DOI: 10.1111/j.1365-2958.2005.04943.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Sigma54-RNA polymerase (Esigma54) predominantly contacts one face of the DNA helix in the closed promoter complex, and interacts with the upstream enhancer-bound activator via DNA looping. Up to date, the precise face of Esigma54 that contacts the activator to convert the closed complex to an open one remains unclear. By introducing protein-induced DNA bends at precise locations between upstream enhancer sequences and the core promoter of the sigma54-dependent glnAp2 promoter without changing the distance in-between, we observed a strong enhanced or decreased promoter activity, especially on linear DNA templates in vitro. The relative positioning and orientations of Esigma54, DNA bending protein and enhancer-bound activator on linear DNA were determined by in vitro footprinting analysis. Intriguingly, the locations from which the DNA bending protein exerted its optimal stimulatory effects were all found on the opposite face of the DNA helix compared with the DNA bound Esigma54 in the closed complex. Therefore, these results provide evidence that the activator must approach the Esigma54 closed complexes from the unbound face of the promoter DNA helix to catalyse open complex formation. This proposal is further supported by the modelling of activator-promoter DNA-Esigma54 complex.
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Affiliation(s)
- Yi-Xin Huo
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of life Sciences, Peking University, Beijing 100871, China
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Chen Y, Yang E, Liu Z, Tian Z, Wang Y. The role of CopG mediated DNA bending on the regulation of the σ54-dependent promoters in E. coli. CHINESE SCIENCE BULLETIN-CHINESE 2006. [DOI: 10.1007/s11434-006-0934-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Commichau FM, Forchhammer K, Stülke J. Regulatory links between carbon and nitrogen metabolism. Curr Opin Microbiol 2006; 9:167-72. [PMID: 16458044 DOI: 10.1016/j.mib.2006.01.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Accepted: 01/20/2006] [Indexed: 10/25/2022]
Abstract
The metabolism of carbon- and nitrogen-containing compounds is fundamental to all forms of life. To cope with changing environmental conditions, bacteria have to sense the nutrient supply and adapt their metabolism accordingly. In addition to nutrient- and pathway-specific responses, they integrate information from the different branches of metabolism to coordinate the control of the expression of many metabolic genes. Two major players interconnecting carbon and nitrogen regulation are the PII proteins and the phosphotransferase system. Moreover, several DNA-binding transcription regulators sense signals are derived from both carbon and nitrogen metabolism. The regulatory networks enable the bacteria to make the appropriate metabolic responses to changing nutrient availabilities in the environment.
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Affiliation(s)
- Fabian M Commichau
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
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Lee SK, Newman JD, Keasling JD. Catabolite repression of the propionate catabolic genes in Escherichia coli and Salmonella enterica: evidence for involvement of the cyclic AMP receptor protein. J Bacteriol 2005; 187:2793-800. [PMID: 15805526 PMCID: PMC1070369 DOI: 10.1128/jb.187.8.2793-2800.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies with Salmonella enterica serovar Typhimurium LT2 demonstrated that transcriptional activation of the prpBCDE operon requires the function of transcription factor PrpR, sigma-54, and IHF. In this study, we found that transcription from the prpBCDE and prpR promoters was down-regulated by the addition of glucose or glycerol, indicating that these genes may be regulated by the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex. Targeted mutagenesis of a putative CRP-binding site in the promoter region between prpR and prpBCDE suggested that these genes are under the control of CRP. Furthermore, cells with defects in cya or crp exhibited reduced transcriptional activation of prpR and prpBCDE in Escherichia coli. These results demonstrate that propionate metabolism is subject to catabolite repression by the global transcriptional regulator CRP and that this regulation is effected through control of both the regulator gene prpR and the prpBCDE operon itself. The unique properties of the regulation of these two divergent promoters may have important implications for mechanisms of CRP-dependent catabolite repression acting in conjunction with a member of the sigma-54 family of transcriptional activators.
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Affiliation(s)
- Sung Kuk Lee
- Department of Chemical Engineering, University of California, Berkeley, CA 94720-1462, USA
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Lilja AE, Jenssen JR, Kahn JD. Geometric and dynamic requirements for DNA looping, wrapping and unwrapping in the activation of E.coli glnAp2 transcription by NtrC. J Mol Biol 2004; 342:467-78. [PMID: 15327947 DOI: 10.1016/j.jmb.2004.07.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 07/06/2004] [Accepted: 07/09/2004] [Indexed: 10/26/2022]
Abstract
Transcriptional activation by the E.coli NtrC protein can occur via DNA looping between a DNA-bound activator and the target sigma(54) RNA polymerase. NtrC forms an octamer on DNA that is capable of binding two DNA molecules. Its ATPase activity is required for open complex formation. Geometric requirements for activation were assessed using a library of DNA bending sequences created by random ligation of A-tract oligonucleotides, as well as several designed sequences. Thirty random or designed sequences with a variety of DNA lengths and bending geometries were cloned in plasmids, and the library was used to replace the spacer between the NtrC binding sites and the core glnAp2 promoter. The activity of each promoter construct under nitrogen limitation was determined in vivo, in a lambda phage lacZ reporter system integrated as a single-copy lysogen to avoid titrating NtrC or polymerase. A wide variety of bending geometries was found to support a similar level of transcriptional activation ( approximately 3-4-fold). Computer modeling of the DNA trajectories suggests that the most inactive promoters have short spacer DNA and the NtrC sites on the opposite side of the helix as the wild-type sites; otherwise, the loop can form effectively. Flexibility and multivalency of the NtrC-Esigma(54) interaction apparently provides substantial independence from DNA stiffness constraints, and in general activation requires less efficient looping than repression. However, none of the random templates were as active as wild-type promoter. Subsidiary activator binding sites in the wild-type were found to be required for full activity, but, surprisingly, these sites could not be functionally replaced by strong binding sites. This suggests that one or more protomers in the NtrC octamer must form and then release contacts with DNA in order to complete the ATPase cycle and act as an AAA(+) activator of the Esigma(54). This dynamic DNA wrapping around the NtrC octamer is proposed to be necessary for efficient activation, and the wrapping may also reduce adventitious activation of other promoters.
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Affiliation(s)
- Anders E Lilja
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742-2021, USA
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Abstract
Nitrogen limitation in Escherichia coli controls the expression of about 100 genes of the nitrogen regulated (Ntr) response, including the ammonia-assimilating glutamine synthetase. Low intracellular glutamine controls the Ntr response through several regulators, whose activities are modulated by a variety of metabolites. Ntr proteins assimilate ammonia, scavenge nitrogen-containing compounds, and appear to integrate ammonia assimilation with other aspects of metabolism, such as polyamine metabolism and glutamate synthesis. The leucine-responsive regulatory protein (Lrp) controls the synthesis of glutamate synthase, which controls the Ntr response, presumably through its effect on intracellular glutamine. Some Ntr proteins inhibit the expression of some Lrp-activated genes. Guanosine tetraphosphate appears to control Lrp synthesis. In summary, a network of interacting global regulators that senses different aspects of metabolism integrates nitrogen assimilation with other metabolic processes.
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Affiliation(s)
- Larry Reitzer
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, Texas 75080-0688, USA.
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Maheswaran M, Forchhammer K. Carbon-source-dependent nitrogen regulation in Escherichia coli is mediated through glutamine-dependent GlnB signalling. MICROBIOLOGY (READING, ENGLAND) 2003; 149:2163-2172. [PMID: 12904556 DOI: 10.1099/mic.0.26449-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The P(II) signal transduction proteins GlnB and GlnK are uridylylated/deuridylylated in response to the intracellular glutamine level, the primary signal of the cellular nitrogen status. Furthermore, GlnB was shown to be allosterically regulated by 2-oxoglutarate, and thus GlnB was suggested to integrate signals of the cellular carbon and nitrogen status. Receptors of GlnB signal transduction in Escherichia coli are the NtrB/NtrC two-component system and GlnE, an enzyme which adenylylates/deadenylylates glutamine synthetase. In this study, the authors investigated the effect of different carbon sources on the expression of the NtrC-dependent genes glnA and glnK and on the uridylylation status of GlnB and GlnK. With glutamine as nitrogen source, high levels of glnA and glnK expression were obtained when glucose was used as carbon source, but expression was strongly decreased when the cells were grown with poor carbon sources or when cAMP was present. This response correlated with the uridylylation status of GlnB, suggesting that the carbon/cAMP effect was mediated through GlnB uridylylation, a conclusion that was confirmed by mutants of the P(II) signalling pathway. When glutamine was replaced by low concentrations of ammonium as nitrogen source, neither glnAglnK expression nor GlnB uridylylation responded to the carbon source or to cAMP. Furthermore, glutamine synthetase could be rapidly adenylylated in vivo by the external addition of glutamine; however, this occurred only when cells were grown in the presence of cAMP, not in its absence. Together, these results suggest that poor carbon sources, through cAMP signalling, favour glutamine uptake. The cellular glutamine signal is then transduced by uridylyltransferase and GlnB to modulate NtrC-dependent gene expression.
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Affiliation(s)
- Mani Maheswaran
- Institut für Mikrobiologie und Molekularbiologie der Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| | - Karl Forchhammer
- Institut für Mikrobiologie und Molekularbiologie der Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
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Li Z, Sun Y, Mao X, Wang Y. cAMP receptor protein (CRP) downregulatesKlebsiella pneumoniae nif promoters inEscherichia coli. CHINESE SCIENCE BULLETIN-CHINESE 2002. [DOI: 10.1007/bf03184111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ludwig H, Meinken C, Matin A, Stülke J. Insufficient expression of the ilv-leu operon encoding enzymes of branched-chain amino acid biosynthesis limits growth of a Bacillus subtilis ccpA mutant. J Bacteriol 2002; 184:5174-8. [PMID: 12193635 PMCID: PMC135319 DOI: 10.1128/jb.184.18.5174-5178.2002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis ccpA mutant strains exhibit two distinct phenotypes: they are defective in catabolite repression, and their growth on minimal media is strongly impaired. This growth defect is largely due to a lack of expression of the gltAB operon. However, growth is impaired even in the presence of glutamate. Here, we demonstrate that the ccpA mutant strain needs methionine and the branched-chain amino acids for optimal growth. The control of expression of the ilv-leu operon by CcpA provides a novel regulatory link between carbon and amino acid metabolism.
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Affiliation(s)
- Holger Ludwig
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
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Kiupakis AK, Reitzer L. ArgR-independent induction and ArgR-dependent superinduction of the astCADBE operon in Escherichia coli. J Bacteriol 2002; 184:2940-50. [PMID: 12003934 PMCID: PMC135064 DOI: 10.1128/jb.184.11.2940-2950.2002] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For Escherichia coli, growth in the absence of ammonia is termed nitrogen limited and results in the induction of genes that assimilate other nitrogen sources, a response mediated by sigma(54) and nitrogen regulator I (NR(I), also called NtrC). The astCADBE operon, which is required for growth with arginine as the sole nitrogen source, is moderately expressed during general nitrogen limitation and maximally expressed in the presence of arginine. The operon is also induced in stationary phase. Primer extension analysis of E. coli revealed the presence of a sigma(54)-dependent promoter utilized in exponential phase during nitrogen limitation and a sigma(S)-dependent promoter active during stationary phase. We used an ast-lacZ fusion to show that arginine stimulates expression, that ArgR, the arginine repressor, enhances expression from both promoters but is not essential, and that transcription by the two forms of the RNA polymerase is competitive and mutually exclusive. We demonstrated the binding of RNA polymerase holoenzymes, NR(I), and ArgR to the promoter region in vitro. We also reconstituted transcription from both promoters with purified components, which confirmed the accessory role of ArgR for the sigma(54)-dependent promoter. Thus, the ast operon exhibits nitrogen source-specific induction that is unique for an NR(I)-dependent gene. The transcriptional regulation of the ast operon in E. coli differs from that in Salmonella enterica serovar Typhimurium, in which ArgR is required for ast operon expression.
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Affiliation(s)
- Alexandros K Kiupakis
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, Texas 75083-0688, USA
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