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Wang BP, Yin X, Huang MY, Li TY, Long XF, Li Y, Niu FX. A Self-Assembling γPFD-SpyCatcher Hydrogel Scaffold for the Coimmobilization of SpyTag-Enzymes to Facilitate the Catalysis of Regulated Enzymes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:19940-19947. [PMID: 39194331 DOI: 10.1021/acs.jafc.4c03403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
In this study, a γPFD-SpyCatcher hydrogel scaffold with the capacity for spontaneous assembly was established. With a maximum loading capacity of a 1:1 molar ratio with SpyTag-enzymes, the immobilized proteins can not only rapidly provide pure enzymes but also exhibit improved thermal and pH stability. The results of the transmission electron microscopic analysis and the traits they present indicated that SpyCatcher promotes the aggregation of γPFD and the formation of hydrogels. In the cell-free pyruvate synthesis system, the γPFD-SpyCatcher coimmobilized SpyTag-hexokinase (HK), SpyTag-phosphofructokinase (PFK) and SpyTag-pyruvate kinase (PK) were employed, and the production of pyruvate increased by 43, 78 and 47% respectively. In in vitro experiments, the oxidative deamination activity of glutamate dehydrogenase (GDH) coimmobilized with γPFD-SpyCatcher was 38% higher than that of purified enzymes. These findings indicate that the γPFD-SpyCatcher-based hydrogels play an important role in breaking the barrier of regulatory enzymes and will provide more strategies for the development of synthetic biology.
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Affiliation(s)
- Bei-Ping Wang
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Xue Yin
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Ming-Yue Huang
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Tian-Yan Li
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Xiu-Feng Long
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Ya Li
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Fu-Xing Niu
- Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou 545006, China
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Liu GH, Yang S, Han S, Xie CJ, Liu X, Rensing C, Zhou SG. Nitrogen fixation and transcriptome of a new diazotrophic Geomonas from paddy soils. mBio 2023; 14:e0215023. [PMID: 37855611 PMCID: PMC10746287 DOI: 10.1128/mbio.02150-23] [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: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE The ability of Geomonas species to fix nitrogen gas (N2) is an important metabolic feature for its application as a plant growth-promoting rhizobacterium. This research is of great importance as it provides the first comprehensive direct experimental evidence of nitrogen fixation by the genus Geomonas in pure culture. We isolated a number of Geomonas strains from paddy soils and determined that nifH was present in these strains. This study demonstrated that these Geomonas species harbored genes encoding nitrogenase, as do Geobacter and Anaeromyxobacter in the same class of Deltaproteobacteria. We demonstrated N2-dependent growth of Geomonas and determined regulation of gene expression associated with nitrogen fixation. The research establishes and advances our understanding of nitrogen fixation in Geomonas.
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Affiliation(s)
- Guo-Hong Liu
- Institute of Resources, Environment and Soil Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou City, Fujian Province, China
| | - Shang Yang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shuang Han
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Cheng-Jie Xie
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shun-Gui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
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Mohd Din ARJ, Suzuki K, Honjo M, Amano K, Nishimura T, Moriuchi R, Dohra H, Ishizawa H, Kimura M, Tashiro Y, Futamata H. Imbalance in Carbon and Nitrogen Metabolism in Comamonas testosteroni R2 Is Caused by Negative Feedback and Rescued by L-arginine. Microbes Environ 2021; 36. [PMID: 34645730 PMCID: PMC8674442 DOI: 10.1264/jsme2.me21050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The collapse of Comamonas testosteroni R2 under chemostat conditions and the aerobic growth of strain R2 under batch conditions with phenol as the sole carbon source were investigated using physiological and transcriptomic techniques. Phenol-/catechol-degrading activities under chemostat conditions gradually decreased, suggesting that metabolites produced from strain R2 accumulated in the culture, which caused negative feedback. The competitive inhibition of phenol hydroxylase and catechol dioxygenase was observed in a crude extract of the supernatant collected from the collapsed culture. Transcriptomic analyses showed that genes related to nitrogen transport were up-regulated; the ammonium transporter amtB was up-regulated approximately 190-fold in the collapsed status, suggesting an increase in the concentration of ammonium in cells. The transcriptional levels of most of the genes related to gluconeogenesis, glycolysis, the pentose phosphate pathway, and the TCA and urea cycles decreased by ~0.7-fold in the stable status, whereas the activities of glutamate synthase and glutamine synthetase increased by ~2-fold. These results suggest that ammonium was assimilated into glutamate and glutamine via 2-oxoglutarate under the limited supply of carbon skeletons, whereas the synthesis of other amino acids and nucleotides was repressed by 0.6-fold. Furthermore, negative feedback appeared to cause an imbalance between carbon and nitrogen metabolism, resulting in collapse. The effects of amino acids on negative feedback were investigated. L-arginine allowed strain R2 to grow normally, even under growth-inhibiting conditions, suggesting that the imbalance was corrected by the stimulation of the urea cycle, resulting in the rescue of strain R2.
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Affiliation(s)
- Abd Rahman Jabir Mohd Din
- Graduate School of Science and Technology, Shizuoka University.,Innovation Centre in Agritechnology for Advanced Bioprocess, UTM Pagoh Research Center
| | - Kenshi Suzuki
- Microbial Ecotechnology (Social Cooperation Laboratory), Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Masahiro Honjo
- Graduate School of Science and Technology, Shizuoka University
| | - Koki Amano
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University
| | - Tomoka Nishimura
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University
| | - Ryota Moriuchi
- Research Institution of Green Science and Technology, Shizuoka University
| | - Hideo Dohra
- Research Institution of Green Science and Technology, Shizuoka University
| | - Hidehiro Ishizawa
- Research Institution of Green Science and Technology, Shizuoka University
| | - Motohiko Kimura
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University
| | - Yosuke Tashiro
- Graduate School of Science and Technology, Shizuoka University.,Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University
| | - Hiroyuki Futamata
- Graduate School of Science and Technology, Shizuoka University.,Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University.,Research Institution of Green Science and Technology, Shizuoka University
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Rapid Response of Nitrogen Cycling Gene Transcription to Labile Carbon Amendments in a Soil Microbial Community. mSystems 2021; 6:6/3/e00161-21. [PMID: 33975966 PMCID: PMC8125072 DOI: 10.1128/msystems.00161-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A large portion of activity in soil microbial communities occurs in short time frames in response to an increase in C availability, affecting the biogeochemical cycling of nitrogen. These changes are of particular importance as nitrogen represents both a limiting nutrient for terrestrial plants as well as a potential pollutant. Episodic inputs of labile carbon (C) to soil can rapidly stimulate nitrogen (N) immobilization by soil microorganisms. However, the transcriptional patterns that underlie this process remain unclear. In order to better understand the regulation of N cycling in soil microbial communities, we conducted a 48-h laboratory incubation with agricultural soil where we stimulated the uptake of inorganic N by amending the soil with glucose. We analyzed the metagenome and metatranscriptome of the microbial communities at four time points that corresponded with changes in N availability. The relative abundances of genes remained largely unchanged throughout the incubation. In contrast, glucose addition rapidly increased the transcription of genes encoding ammonium and nitrate transporters, enzymes responsible for N assimilation into biomass, and genes associated with the N regulatory network. This upregulation coincided with an increase in transcripts associated with glucose breakdown and oxoglutarate production, demonstrating a connection between C and N metabolism. When concentrations of ammonium were low, we observed a transient upregulation of genes associated with the nitrogen-fixing enzyme nitrogenase. Transcripts for nitrification and denitrification were downregulated throughout the incubation, suggesting that dissimilatory transformations of N may be suppressed in response to labile C inputs in these soils. These results demonstrate that soil microbial communities can respond rapidly to changes in C availability by drastically altering the transcription of N cycling genes. IMPORTANCE A large portion of activity in soil microbial communities occurs in short time frames in response to an increase in C availability, affecting the biogeochemical cycling of nitrogen. These changes are of particular importance as nitrogen represents both a limiting nutrient for terrestrial plants as well as a potential pollutant. However, we lack a full understanding of the short-term effects of labile carbon inputs on the metabolism of microbes living in soil. Here, we found that soil microbial communities responded to labile carbon addition by rapidly transcribing genes encoding proteins and enzymes responsible for inorganic nitrogen acquisition, including nitrogen fixation. This work demonstrates that soil microbial communities respond within hours to carbon inputs through altered gene expression. These insights are essential for an improved understanding of the microbial processes governing soil organic matter production, decomposition, and nutrient cycling in natural and agricultural ecosystems.
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Oliveira A, Rodrigues J, Ferreira EC, Rodrigues L, Dias O. A kinetic model of the central carbon metabolism for acrylic acid production in Escherichia coli. PLoS Comput Biol 2021; 17:e1008704. [PMID: 33684125 PMCID: PMC7971886 DOI: 10.1371/journal.pcbi.1008704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/18/2021] [Accepted: 01/12/2021] [Indexed: 02/06/2023] Open
Abstract
Acrylic acid is a value-added chemical used in industry to produce diapers, coatings, paints, and adhesives, among many others. Due to its economic importance, there is currently a need for new and sustainable ways to synthesise it. Recently, the focus has been laid in the use of Escherichia coli to express the full bio-based pathway using 3-hydroxypropionate as an intermediary through three distinct pathways (glycerol, malonyl-CoA, and β-alanine). Hence, the goals of this work were to use COPASI software to assess which of the three pathways has a higher potential for industrial-scale production, from either glucose or glycerol, and identify potential targets to improve the biosynthetic pathways yields. When compared to the available literature, the models developed during this work successfully predict the production of 3-hydroxypropionate, using glycerol as carbon source in the glycerol pathway, and using glucose as a carbon source in the malonyl-CoA and β-alanine pathways. Finally, this work allowed to identify four potential over-expression targets (glycerol-3-phosphate dehydrogenase (G3pD), acetyl-CoA carboxylase (AccC), aspartate aminotransferase (AspAT), and aspartate carboxylase (AspC)) that should, theoretically, result in higher AA yields.
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Affiliation(s)
| | - Joana Rodrigues
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | | | - Lígia Rodrigues
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Oscar Dias
- Centre of Biological Engineering, University of Minho, Braga, Portugal
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Cheng B, Wan L, Armstrong FA. Progress in Scaling up and Streamlining a Nanoconfined, Enzyme-Catalyzed Electrochemical Nicotinamide Recycling System for Biocatalytic Synthesis. ChemElectroChem 2020; 7:4672-4678. [PMID: 33381377 PMCID: PMC7756331 DOI: 10.1002/celc.202001166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/13/2020] [Indexed: 11/05/2022]
Abstract
An electrochemically driven nicotinamide recycling system, referred to as the 'electrochemical leaf' has unique attributes that may suit it to the small-scale industrial synthesis of high-value chemicals. A complete enzyme cascade can be immobilized within the channels of a nanoporous electrode, allowing complex reactions to be energized, controlled and monitored continuously in real time. The electrode is easily prepared by depositing commercially available indium tin oxide (ITO) nanoparticles on a Ti support, resulting in a network of nanopores into which enzymes enter and bind. One of the enzymes is the photosynthetic flavoenzyme, ferredoxin NADP+ reductase (FNR), which catalyzes the quasi-reversible electrochemical recycling of NADP(H) and serves as the transducer. The second enzyme is any NADP(H)-dependent dehydrogenase of choice, and further enzymes can be added to build elaborate cascades that are driven in either oxidation or reduction directions through the rapid recycling of NADP(H) within the pores. In this Article, we describe the measurement of key enzyme/cofactor parameters and an essentially linear scale-up from an analytical scale 4 mL reactor with a 14 cm2 electrode to a 500 mL reactor with a 500 cm2 electrode. We discuss the advantages (energization, continuous monitoring that can be linked to a computer, natural enzyme immobilization, low costs of electrodes and low cofactor requirements) and challenges to be addressed (optimizing minimal use of enzyme applied to the electrode).
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Affiliation(s)
- Beichen Cheng
- Department of ChemistryUniversity of OxfordInorganic Chemistry LaboratorySouth Parks RoadOxfordOX1 3QR
| | - Lei Wan
- Department of ChemistryUniversity of OxfordInorganic Chemistry LaboratorySouth Parks RoadOxfordOX1 3QR
| | - Fraser A. Armstrong
- Department of ChemistryUniversity of OxfordInorganic Chemistry LaboratorySouth Parks RoadOxfordOX1 3QR
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7
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Mikami Y, Yoneda H, Tatsukami Y, Aoki W, Ueda M. Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli. AMB Express 2017; 7:83. [PMID: 28429328 PMCID: PMC5399010 DOI: 10.1186/s13568-017-0385-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/07/2017] [Indexed: 11/10/2022] Open
Abstract
The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber–Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.
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Löffler M, Simen JD, Müller J, Jäger G, Laghrami S, Schäferhoff K, Freund A, Takors R. Switching between nitrogen and glucose limitation: Unraveling transcriptional dynamics in Escherichia coli. J Biotechnol 2017; 258:2-12. [PMID: 28412516 DOI: 10.1016/j.jbiotec.2017.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/09/2017] [Accepted: 04/11/2017] [Indexed: 01/09/2023]
Abstract
Transcriptional control under nitrogen and carbon-limitation conditions have been well analyzed for Escherichia coli. However, the transcriptional dynamics that underlie the shift in regulatory programs from nitrogen to carbon limitation is not well studied. In the present study, cells were cultivated at steady state under nitrogen (ammonia)-limited conditions then shifted to carbon (glucose) limitation to monitor changes in transcriptional dynamics. Nitrogen limitation was found to be dominated by sigma 54 (RpoN) and sigma 38 (RpoS), whereas the "housekeeping" sigma factor 70 (RpoD) and sigma 38 regulate cellular status under glucose limitation. During the transition, nitrogen-mediated control was rapidly redeemed and mRNAs that encode active uptake systems, such as ptsG and manXYZ, were quickly amplified. Next, genes encoding facilitators such as lamB were overexpressed, followed by high affinity uptake systems such as mglABC and non-specific porins such as ompF. These regulatory programs are complex and require well-equilibrated and superior control. At the metabolome level, 2-oxoglutarate is the likely component that links carbon- and nitrogen-mediated regulation by interacting with major regulatory elements. In the case of dual glucose and ammonia limitation, sigma 24 (RpoE) appears to play a key role in orchestrating these complex regulatory networks.
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Affiliation(s)
- Michael Löffler
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany
| | - Joana Danica Simen
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany
| | - Jan Müller
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany
| | - Günter Jäger
- University of Tübingen, Institute of Medical Genetics and Applied Genomics, Calwerstr. 7, 72076 Tübingen, Germany
| | - Salaheddine Laghrami
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany
| | - Karin Schäferhoff
- University of Tübingen, Institute of Medical Genetics and Applied Genomics, Calwerstr. 7, 72076 Tübingen, Germany
| | - Andreas Freund
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany
| | | | - Ralf Takors
- University of Stuttgart, Institute of Biochemical Engineering, Allmandring 31, 70569 Stuttgart, Germany.
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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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Walvekar AS, Choudhury R, Punekar NS. Mixed disulfide formation at Cys141 leads to apparent unidirectional attenuation of Aspergillus niger NADP-glutamate dehydrogenase activity. PLoS One 2014; 9:e101662. [PMID: 24987966 PMCID: PMC4079599 DOI: 10.1371/journal.pone.0101662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 06/09/2014] [Indexed: 11/19/2022] Open
Abstract
NADP-Glutamate dehydrogenase from Aspergillus niger (AnGDH) exhibits sigmoid 2-oxoglutarate saturation. Incubation with 2-hydroxyethyl disulfide (2-HED, the disulfide of 2-mercaptoethanol) resulted in preferential attenuation of AnGDH reductive amination (forward) activity but with a negligible effect on oxidative deamination (reverse) activity, when monitored in the described standard assay. Such a disulfide modified AnGDH displaying less than 1.0% forward reaction rate could be isolated after 2-HED treatment. This unique forward inhibited GDH form (FIGDH), resembling a hypothetical 'one-way' active enzyme, was characterized. Kinetics of 2-HED mediated inhibition and protein thiol titrations suggested that a single thiol group is modified in FIGDH. Two site-directed cysteine mutants, C141S and C415S, were constructed to identify the relevant thiol in FIGDH. The forward activity of C141S alone was insensitive to 2-HED, implicating Cys141 in FIGDH formation. It was observed that FIGDH displayed maximal reaction rate only after a pre-incubation with 2-oxoglutarate and NADPH. In addition, compared to the native enzyme, FIGDH showed a four fold increase in K0.5 for 2-oxoglutarate and a two fold increase in the Michaelis constants for ammonium and NADPH. With no change in the GDH reaction equilibrium constant, the FIGDH catalyzed rate of approach to equilibrium from reductive amination side was sluggish. Altered kinetic properties of FIGDH at least partly account for the observed apparent loss of forward activity when monitored under defined assay conditions. In sum, although Cys141 is catalytically not essential, its covalent modification provides a striking example of converting the biosynthetic AnGDH into a catabolic enzyme.
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Affiliation(s)
- Adhish S. Walvekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Rajarshi Choudhury
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Narayan S. Punekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
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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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Sharkey MA, Oliveira TF, Engel PC, Khan AR. Structure of NADP(+)-dependent glutamate dehydrogenase from Escherichia coli--reflections on the basis of coenzyme specificity in the family of glutamate dehydrogenases. FEBS J 2013; 280:4681-92. [PMID: 23879525 DOI: 10.1111/febs.12439] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 07/10/2013] [Accepted: 07/16/2013] [Indexed: 11/26/2022]
Abstract
Glutamate dehydrogenases (GDHs; EC 1.4.1.2-4) catalyse the oxidative deamination of L-glutamate to α-ketoglutarate, using NAD(+) and/or NADP(+) as a cofactor. Subunits of homo-hexameric bacterial enzymes comprise a substrate-binding domain I followed by a nucleotide-binding domain II. The reaction occurs in a catalytic cleft between the two domains. Although conserved residues in the nucleotide-binding domains of various dehydrogenases have been linked to cofactor preferences, the structural basis for specificity in the GDH family remains poorly understood. Here, the refined crystal structure of Escherichia coli GDH in the absence of reactants is described at 2.5-Å resolution. Modelling of NADP(+) in domain II reveals the potential contribution of positively charged residues from a neighbouring α-helical hairpin to phosphate recognition. In addition, a serine that follows the P7 aspartate is presumed to form a hydrogen bond with the 2'-phosphate. Mutagenesis and kinetic analysis confirms the importance of these residues in NADP(+) recognition. Surprisingly, one of the positively charged residues is conserved in all sequences of NAD(+)-dependent enzymes, but the conformations adopted by the corresponding regions in proteins whose structure has been solved preclude their contribution to the coordination of the 2'-ribose phosphate of NADP(+). These studies clarify the sequence-structure relationships in bacterial GDHs, revealing that identical residues may specify different coenzyme preferences, depending on the structural context. Primary sequence alone is therefore not a reliable guide for predicting coenzyme specificity. We also consider how it is possible for a single sequence to accommodate both coenzymes in the dual-specificity GDHs of animals.
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Affiliation(s)
- Michael A Sharkey
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Ireland
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13
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Zheng H, Beliavsky A, Tchigvintsev A, Brunzelle JS, Brown G, Flick R, Evdokimova E, Wawrzak Z, Mahadevan R, Anderson WF, Savchenko A, Yakunin AF. Structure and activity of the NAD(P)+-dependent succinate semialdehyde dehydrogenase YneI from Salmonella typhimurium. Proteins 2013; 81:1031-41. [PMID: 23229889 DOI: 10.1002/prot.24227] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/18/2012] [Indexed: 01/25/2023]
Abstract
Aldehyde dehydrogenases are found in all organisms and play an important role in the metabolic conversion and detoxification of endogenous and exogenous aldehydes. Genomes of many organisms including Escherichia coli and Salmonella typhimurium encode two succinate semialdehyde dehydrogenases with low sequence similarity and different cofactor preference (YneI and GabD). Here, we present the crystal structure and biochemical characterization of the NAD(P)(+)-dependent succinate semialdehyde dehydrogenase YneI from S. typhimurium. This enzyme shows high activity and affinity toward succinate semialdehyde and exhibits substrate inhibition at concentrations of SSA higher than 0.1 mM. YneI can use both NAD(+) and NADP(+) as cofactors, although affinity to NAD(+) is 10 times higher. High resolution crystal structures of YneI were solved in a free state (1.85 Å) and in complex with NAD(+) (1.90 Å) revealing a two domain protein with the active site located in the interdomain interface. The NAD(+) molecule is bound in the long channel with its nicotinamide ring positioned close to the side chain of the catalytic Cys268. Site-directed mutagenesis demonstrated that this residue, as well as the conserved Trp136, Glu365, and Asp426 are important for activity of YneI, and that the conserved Lys160 contributes to the enzyme preference to NAD(+) . Our work has provided further insight into the molecular mechanisms of substrate selectivity and activity of succinate semialdehyde dehydrogenases.
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Affiliation(s)
- Hongyan Zheng
- Department of Chemical Engineering and Applied Chemistry, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
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Garcia-Galan C, Barbosa O, Fernandez-Lafuente R. Stabilization of the hexameric glutamate dehydrogenase from Escherichia coli by cations and polyethyleneimine. Enzyme Microb Technol 2013; 52:211-7. [PMID: 23540921 DOI: 10.1016/j.enzmictec.2013.02.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/19/2013] [Accepted: 02/21/2013] [Indexed: 12/21/2022]
Abstract
The enzyme glutamate dehydrogenase (GDH) from Escherichia coli is a hexameric protein. The stability of this enzyme was increased in the presence of Li(+) in concentrations ranging from 1 to 10mM, 1M of sodium phosphate, or 1M ammonium sulfate. A very significant dependence of the enzyme stability on protein concentration was found, suggesting that subunit dissociation could be the first step of GDH inactivation. This effect of enzyme concentration on its stability was not significantly decreased by the presence of 10mM Li(+). Subunit crosslinking could not be performed using neither dextran nor glutaraldehyde because both reagents readily inactivated GDH. Thus, they were discarded as crosslinking reagents and GDH was incubated in the presence of polyethyleneimine (PEI) with the aim of physically crosslinking the enzyme subunits. This incubation does not have a significant effect on enzyme activity. However, after optimization, the PEI-GDH was found to almost maintain the full initial activity after 2h under conditions where the untreated enzyme retained only 20% of the initial activity, and the effect of the enzyme concentration on enzyme stability almost disappeared. This stabilization was maintained in the pH range 5-9, but it was lost at high ionic strength. This PEI-GDH composite was also much more stable than the unmodified enzyme in stirred systems. The results suggested that a real adsorption of the PEI on the GDH surface was required to obtain this stabilizing effect. A positive effect of Li(+) on enzyme stability was maintained after enzyme surface coating with PEI, suggesting that the effects of both stabilizing agents could not be exactly based on the same mechanism. Thus, the coating of GDH surface with PEI seems to be a good alternative to have a stabilized and soluble composite of the enzyme.
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Affiliation(s)
- Cristina Garcia-Galan
- Departamento de Biocatálisis, ICP-CSIC, Campus UAM, Cantoblanco, 28049 Madrid, Spain
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Gunka K, Commichau FM. Control of glutamate homeostasis in Bacillus subtilis: a complex interplay between ammonium assimilation, glutamate biosynthesis and degradation. Mol Microbiol 2012; 85:213-24. [DOI: 10.1111/j.1365-2958.2012.08105.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Boogerd FC, Ma H, Bruggeman FJ, van Heeswijk WC, García-Contreras R, Molenaar D, Krab K, Westerhoff HV. AmtB-mediated NH3
transport in prokaryotes must be active and as a consequence regulation of transport by GlnK is mandatory to limit futile cycling of NH4+/NH3. FEBS Lett 2010; 585:23-8. [DOI: 10.1016/j.febslet.2010.11.055] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 11/29/2010] [Accepted: 11/29/2010] [Indexed: 12/19/2022]
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Gunka K, Newman JA, Commichau FM, Herzberg C, Rodrigues C, Hewitt L, Lewis RJ, Stülke J. Functional dissection of a trigger enzyme: mutations of the bacillus subtilis glutamate dehydrogenase RocG that affect differentially its catalytic activity and regulatory properties. J Mol Biol 2010; 400:815-27. [PMID: 20630473 DOI: 10.1016/j.jmb.2010.05.055] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/20/2010] [Accepted: 05/22/2010] [Indexed: 11/12/2022]
Abstract
Any signal transduction requires communication between a sensory component and an effector. Some enzymes engage in signal perception and transduction, as well as in catalysis, and these proteins are known as "trigger" enzymes. In this report, we detail the trigger properties of RocG, the glutamate dehydrogenase of Bacillus subtilis. RocG not only deaminates the key metabolite glutamate to form alpha-ketoglutarate but also interacts directly with GltC, a LysR-type transcription factor that regulates glutamate biosynthesis from alpha-ketoglutarate, thus linking the two metabolic pathways. We have isolated mutants of RocG that separate the two functions. Several mutations resulted in permanent inactivation of GltC as long as a source of glutamate was present. These RocG proteins have lost their ability to catabolize glutamate due to a strongly reduced affinity for glutamate. The second class of mutants is exemplified by the replacement of aspartate residue 122 by asparagine. This mutant protein has retained enzymatic activity but has lost the ability to control the activity of GltC. Crystal structures of glutamate dehydrogenases that permit a molecular explanation of the properties of the various mutants are presented. Specifically, we may propose that D122N replacement affects the surface of RocG. Our data provide evidence for a correlation between the enzymatic activity of RocG and its ability to inactivate GltC, and thus give insights into the mechanism that couples the enzymatic activity of a trigger enzyme to its regulatory function.
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Affiliation(s)
- Katrin Gunka
- Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
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Sharkey MA, Engel PC. Modular coenzyme specificity: a domain-swopped chimera of glutamate dehydrogenase. Proteins 2009; 77:268-78. [PMID: 19425107 DOI: 10.1002/prot.22433] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Domain-swopped chimeras of the glutamate dehydrogenases from Clostridium symbiosum (CsGDH) (NAD(+)-specific) and Escherichia coli (EcGDH) (NADP(+)-specific) have been produced, with the aim of testing the localization of determinants of coenzyme specificity. An active chimera consisting of the substrate-binding domain (Domain I) of CsGDH and the coenzyme-binding domain (Domain II) of EcGDH has been purified to homogeneity, and a thorough kinetic analysis has been carried out. Results indicate that selectivity for the phosphorylated coenzyme does indeed reside solely in Domain II; the chimera utilizes NAD(+) at 0.8% of the rate observed with NADP(+), similar to the 0.5% ratio for EcGDH. Positive cooperativity toward L-glutamate, characteristic of CsGDH, has been retained with Domain I. An unforeseen feature of this chimera, however, is that, although glutamate cooperativity occurs only at higher pH values in the parent CsGDH, the chimeric protein shows it over the full pH range explored. Also surprising is that the chimera is capable of catalysing severalfold higher reaction rates (V(max)) in both directions than either of the parent enzymes from which it is constructed.
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Affiliation(s)
- Michael A Sharkey
- UCD School of Biomolecular and Biomedical Sciences, Conway Institute, University College Dublin, Belfield, Dublin 4, Republic of Ireland.
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