1
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Hellweg L, Pfeifer M, Tarnawski M, Thing-Teoh S, Chang L, Bergner A, Kress J, Hiblot J, Wiedmer T, Superti-Furga G, Reinhardt J, Johnsson K, Leippe P. AspSnFR: A genetically encoded biosensor for real-time monitoring of aspartate in live cells. Cell Chem Biol 2024; 31:1529-1541.e12. [PMID: 38806058 DOI: 10.1016/j.chembiol.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/11/2024] [Accepted: 05/01/2024] [Indexed: 05/30/2024]
Abstract
Aspartate is crucial for nucleotide synthesis, ammonia detoxification, and maintaining redox balance via the malate-aspartate-shuttle (MAS). To disentangle these multiple roles of aspartate metabolism, tools are required that measure aspartate concentrations in real time and in live cells. We introduce AspSnFR, a genetically encoded green fluorescent biosensor for intracellular aspartate, engineered through displaying and screening biosensor libraries on mammalian cells. In live cells, AspSnFR is able to precisely and quantitatively measure cytosolic aspartate concentrations and dissect its production from glutamine. Combining high-content imaging of AspSnFR with pharmacological perturbations exposes differences in metabolic vulnerabilities of aspartate levels based on nutrient availability. Further, AspSnFR facilitates tracking of aspartate export from mitochondria through SLC25A12, the MAS' key transporter. We show that SLC25A12 is a rapidly responding and direct route to couple Ca2+ signaling with mitochondrial aspartate export. This establishes SLC25A12 as a crucial link between cellular signaling, mitochondrial respiration, and metabolism.
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Affiliation(s)
- Lars Hellweg
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany; Heidelberg University, Heidelberg, Germany
| | - Martin Pfeifer
- Novartis Biomedical Research, Discovery Science, Basel, Switzerland
| | - Miroslaw Tarnawski
- Protein Expression and Characterization Facility, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Shao Thing-Teoh
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Lena Chang
- Novartis Biomedical Research, Discovery Science, Basel, Switzerland
| | - Andrea Bergner
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Jana Kress
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Julien Hiblot
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria; Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Jürgen Reinhardt
- Novartis Biomedical Research, Discovery Science, Basel, Switzerland
| | - Kai Johnsson
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany; Institute of Chemical Sciences and Engineering (ISIC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Philipp Leippe
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany; CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.
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2
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Lai D, Hedlund BP, Mau RL, Jiao JY, Li J, Hayer M, Dijkstra P, Schwartz E, Li WJ, Dong H, Palmer M, Dodsworth JA, Zhou EM, Hungate BA. Resource partitioning and amino acid assimilation in a terrestrial geothermal spring. THE ISME JOURNAL 2023; 17:2112-2122. [PMID: 37741957 PMCID: PMC10579274 DOI: 10.1038/s41396-023-01517-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/31/2023] [Accepted: 09/13/2023] [Indexed: 09/25/2023]
Abstract
High-temperature geothermal springs host simplified microbial communities; however, the activities of individual microorganisms and their roles in the carbon cycle in nature are not well understood. Here, quantitative stable isotope probing (qSIP) was used to track the assimilation of 13C-acetate and 13C-aspartate into DNA in 74 °C sediments in Gongxiaoshe Hot Spring, Tengchong, China. This revealed a community-wide preference for aspartate and a tight coupling between aspartate incorporation into DNA and the proliferation of aspartate utilizers during labeling. Both 13C incorporation into DNA and changes in the abundance of taxa during incubations indicated strong resource partitioning and a significant phylogenetic signal for aspartate incorporation. Of the active amplicon sequence variants (ASVs) identified by qSIP, most could be matched with genomes from Gongxiaoshe Hot Spring or nearby springs with an average nucleotide similarity of 99.4%. Genomes corresponding to aspartate primary utilizers were smaller, near-universally encoded polar amino acid ABC transporters, and had codon preferences indicative of faster growth rates. The most active ASVs assimilating both substrates were not abundant, suggesting an important role for the rare biosphere in the community response to organic carbon addition. The broad incorporation of aspartate into DNA over acetate by the hot spring community may reflect dynamic cycling of cell lysis products in situ or substrates delivered during monsoon rains and may reflect N limitation.
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Affiliation(s)
- Dengxun Lai
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA.
- Nevada Institute for Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA.
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Junhui Li
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Hailiang Dong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China and Department of Geology and Environmental Earth Science, Miami University, Oxford, OH, USA
| | - Marike Palmer
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jeremy A Dodsworth
- Department of Biology, California State University, San Bernardino, CA, USA
| | - En-Min Zhou
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
- School of Resource Environment and Earth Science, Yunnan University, Kunming, China
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
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3
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Castro-Rodríguez V, Kleist TJ, Gappel NM, Atanjaoui F, Okumoto S, Machado M, Denyer T, Timmermans MCP, Frommer WB, Wudick MM. Sponging of glutamate at the outer plasma membrane surface reveals roles for glutamate in development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:664-674. [PMID: 34783104 DOI: 10.1111/tpj.15585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Plants use electrical and chemical signals for systemic communication. Herbivory, for instance, appears to trigger local apoplasmic glutamate accumulation, systemic electrical signals, and calcium waves that travel to report insect damage to neighboring leaves and initiate defense. To monitor extra- and intracellular glutamate concentrations in plants, we generated Arabidopsis lines expressing genetically encoded fluorescent glutamate sensors. In contrast to cytosolically localized sensors, extracellularly displayed variants inhibited plant growth and proper development. Phenotypic analyses of high-affinity display sensor lines revealed that root meristem development, particularly the quiescent center, number of lateral roots, vegetative growth, and floral architecture were impacted. Notably, the severity of the phenotypes was positively correlated with the affinity of the display sensors, intimating that their ability to sequester glutamate at the surface of the plasma membrane was responsible for the defects. Root growth defects were suppressed by supplementing culture media with low levels of glutamate. Together, the data indicate that sequestration of glutamate at the cell surface either disrupts the supply of glutamate to meristematic cells and/or impairs localized glutamatergic signaling important for developmental processes.
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Affiliation(s)
| | - Thomas J Kleist
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Nicoline M Gappel
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Fatiha Atanjaoui
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Sakiko Okumoto
- Department of Soil and Crop Science, Texas A&M, College Station, TX, USA
| | - Mackenzie Machado
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Tom Denyer
- Center for Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 32, Tübingen, 72076, Germany
| | - Marja C P Timmermans
- Center for Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 32, Tübingen, 72076, Germany
| | - Wolf B Frommer
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | - Michael M Wudick
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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4
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Li T, Wang J, Cao Q, Li F, Han J, Zhu B, Zhang Y, Niu H. Identification of Novel Genes Involved in Escherichia coli Persistence to Tosufloxacin. Front Cell Infect Microbiol 2020; 10:581986. [PMID: 33117736 PMCID: PMC7561378 DOI: 10.3389/fcimb.2020.581986] [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] [Received: 07/10/2020] [Accepted: 09/01/2020] [Indexed: 11/28/2022] Open
Abstract
Persisters are metabolically quiescent phenotypic variants of the wild type that are tolerant to cidal antibiotics, and the mechanisms of persister formation and survival are complex and not completely understood. To identify genes involved in persistence to tosufloxacin, which has higher activity against persisters than most other quinolones, we screened the E. coli KEIO mutant library using a different condition from most persister mutant screens (6 h) with a longer exposure of 18 h with tosufloxacin. We identified 18 mutants (acrA, acrB, ddlB, dnaG, gltI, hlpA, lpcA, recG, recN, rfaH, ruvC, surA, tatC, tolQ, uvrD, xseA, and ydfI) that failed to form tosufloxacin tolerant persisters. Among them, gltI, hlpA, ruvC, ddlB, ydfI, and tatC are unique genes involved in E. coli persistence to tosufloxacin which have not been reported before. Furthermore, deletion mutants in genes coding periplasmic proteins (surA, lpcA, hlpA, and gltI) had more defect in persistence to tosufloxacin than the other identified mutants, with surA and lpcA mutants being the most prominent. The “deep” persister phenotype of surA and lpcA mutants was further confirmed both in vitro and in vivo. Compared with the wild type strain E. coli BW25113 in vitro, the persister phenotype of the surA and lpcA mutants was decreased more than 100–1,000-fold in persistence to various antibiotics, acidic, hyperosmotic and heat conditions. In addition, in both stationary phase bacteria and biofilm bacteria infection mouse models, the surA and lpcA mutants had lower survival and persistence than the parent uropathogenic strain UTI89, suggesting that the in vitro identified persister mechanisms (surA and lpcA) are operative and valid for in vivo persistence. Our findings provide new insight into the mechanisms of persister formation and maintenance under tosufloxacin and will likely provide novel therapeutic and vaccine targets for developing more effective treatment and prevention of persistent E. coli infections.
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Affiliation(s)
- Tuodi Li
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Juan Wang
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Qianqian Cao
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Fei Li
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Jiangyuan Han
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Bingdong Zhu
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Ying Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Hongxia Niu
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
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5
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Strecker A, Schubert C, Zedler S, Steinmetz P, Unden G. DcuA of aerobically grownEscherichia coliserves as a nitrogen shuttle (L‐aspartate/fumarate) for nitrogen uptake. Mol Microbiol 2018; 109:801-811. [DOI: 10.1111/mmi.14074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/27/2018] [Accepted: 07/02/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Strecker
- Microbiology and Wine Research, Institute of Molecular Physiology (IMP) Johannes Gutenberg‐University Mainz Mainz 55099Germany
| | - Christopher Schubert
- Microbiology and Wine Research, Institute of Molecular Physiology (IMP) Johannes Gutenberg‐University Mainz Mainz 55099Germany
| | - Sandra Zedler
- Microbiology and Wine Research, Institute of Molecular Physiology (IMP) Johannes Gutenberg‐University Mainz Mainz 55099Germany
| | - Philipp Steinmetz
- Microbiology and Wine Research, Institute of Molecular Physiology (IMP) Johannes Gutenberg‐University Mainz Mainz 55099Germany
| | - Gottfried Unden
- Microbiology and Wine Research, Institute of Molecular Physiology (IMP) Johannes Gutenberg‐University Mainz Mainz 55099Germany
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6
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Gagliardi A, Lamboglia E, Bianchi L, Landi C, Armini A, Ciolfi S, Bini L, Marri L. Proteomics analysis of a long-term survival strain of Escherichia coli K-12 exhibiting a growth advantage in stationary-phase (GASP) phenotype. Proteomics 2016; 16:963-72. [PMID: 26711811 DOI: 10.1002/pmic.201500314] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/24/2015] [Accepted: 12/23/2015] [Indexed: 01/14/2023]
Abstract
The aim of this work was the functional and proteomic analysis of a mutant, W3110 Bgl(+) /10, isolated from a batch culture of an Escherichia coli K-12 strain maintained at room temperature without addition of nutrients for 10 years. When the mutant was evaluated in competition experiments in co-culture with the wild-type, it exhibited the growth advantage in stationary phase (GASP) phenotype. Proteomes of the GASP mutant and its parental strain were compared by using a 2DE coupled with MS approach. Several differentially expressed proteins were detected and many of them were successful identified by mass spectrometry. Identified expression-changing proteins were grouped into three functional categories: metabolism, protein synthesis, chaperone and stress responsive proteins. Among them, the prevalence was ascribable to the "metabolism" group (72%) for the GASP mutant, and to "chaperones and stress responsive proteins" group for the parental strain (48%).
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Affiliation(s)
| | | | - Laura Bianchi
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Claudia Landi
- Department of Life Sciences, University of Siena, Siena, Italy
| | | | - Silvia Ciolfi
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Luca Bini
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Laura Marri
- Department of Life Sciences, University of Siena, Siena, Italy
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7
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Clifton BE, Jackson CJ. Ancestral Protein Reconstruction Yields Insights into Adaptive Evolution of Binding Specificity in Solute-Binding Proteins. Cell Chem Biol 2016; 23:236-245. [PMID: 26853627 DOI: 10.1016/j.chembiol.2015.12.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/30/2015] [Accepted: 12/19/2015] [Indexed: 11/15/2022]
Abstract
The promiscuous functions of proteins are an important reservoir of functional novelty in protein evolution, but the molecular basis for binding promiscuity remains elusive. We used ancestral protein reconstruction to experimentally characterize evolutionary intermediates in the functional expansion of the polar amino acid-binding protein family, which has evolved to bind a variety of amino acids with high affinity and specificity. High-resolution crystal structures of an ancestral arginine-binding protein in complex with l-arginine and l-glutamine show that the promiscuous binding of l-glutamine is enabled by multi-scale conformational plasticity, water-mediated interactions, and selection of an alternative conformational substate productive for l-glutamine binding. Evolution of specialized glutamine-binding proteins from this ancestral protein was achieved by displacement of water molecules from the protein-ligand interface, reducing the entropic penalty associated with the promiscuous interaction. These results provide a structural and thermodynamic basis for the co-option of a promiscuous interaction in the evolution of binding specificity.
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Affiliation(s)
- Ben E Clifton
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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8
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Miyakoshi M, Chao Y, Vogel J. Cross talk between ABC transporter mRNAs via a target mRNA-derived sponge of the GcvB small RNA. EMBO J 2015; 34:1478-92. [PMID: 25630703 PMCID: PMC4474525 DOI: 10.15252/embj.201490546] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 11/16/2022] Open
Abstract
There is an expanding list of examples by which one mRNA can posttranscriptionally influence the expression of others. This can involve RNA sponges that sequester regulatory RNAs of mRNAs in the same regulon, but the underlying molecular mechanism of such mRNA cross talk remains little understood. Here, we report sponge-mediated mRNA cross talk in the posttranscriptional network of GcvB, a conserved Hfq-dependent small RNA with one of the largest regulons known in bacteria. We show that mRNA decay from the gltIJKL locus encoding an amino acid ABC transporter generates a stable fragment (SroC) that base-pairs with GcvB. This interaction triggers the degradation of GcvB by RNase E, alleviating the GcvB-mediated mRNA repression of other amino acid-related transport and metabolic genes. Intriguingly, since the gltIJKL mRNA itself is a target of GcvB, the SroC sponge seems to enable both an internal feed-forward loop to activate its parental mRNA in cis and activation of many trans-encoded mRNAs in the same pathway. Disabling this mRNA cross talk affects bacterial growth when peptides are the sole carbon and nitrogen sources.
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Affiliation(s)
- Masatoshi Miyakoshi
- RNA Biology Group, Institute for Molecular Infection Biology University of Würzburg, Würzburg, Germany
| | - Yanjie Chao
- RNA Biology Group, Institute for Molecular Infection Biology University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology University of Würzburg, Würzburg, Germany
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9
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Hu Y, Fan CP, Fu G, Zhu D, Jin Q, Wang DC. Crystal Structure of a Glutamate/Aspartate Binding Protein Complexed with a Glutamate Molecule: Structural Basis of Ligand Specificity at Atomic Resolution. J Mol Biol 2008; 382:99-111. [DOI: 10.1016/j.jmb.2008.06.091] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/29/2008] [Accepted: 06/26/2008] [Indexed: 11/30/2022]
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10
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Müller A, León-Kempis MDR, Dodson E, Wilson KS, Wilkinson AJ, Kelly DJ. A Bacterial Virulence Factor with a Dual Role as an Adhesin and a Solute-binding Protein: The Crystal Structure at 1.5 Å Resolution of the PEB1a Protein from the Food-borne Human Pathogen Campylobacter jejuni. J Mol Biol 2007; 372:160-71. [PMID: 17631313 DOI: 10.1016/j.jmb.2007.06.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 06/13/2007] [Accepted: 06/14/2007] [Indexed: 12/20/2022]
Abstract
The PEB1a protein is an antigenic factor exposed on the surface of the food-borne human pathogen Campylobacter jejuni, which has a major role in adherence and host colonisation. PEB1a is also the periplasmic binding protein component of an aspartate/glutamate ABC transporter essential for optimal microaerobic growth on these dicarboxylic amino acids. Here, we report the crystal structure of PEB1a at 1.5 A resolution. The protein has a typical two-domain alpha/beta structure, characteristic of periplasmic extracytoplasmic solute receptors and a chain topology related to the type II subfamily. An aspartate ligand, clearly defined by electron density in the interdomain cleft, forms extensive polar interactions with the protein, the majority of which are made with the larger domain. Arg89 and Asp174 form ion-pairing interactions with the main chain alpha-carboxyl and alpha-amino-groups, respectively, of the ligand, while Arg67, Thr82, Lys19 and Tyr156 co-ordinate the ligand side-chain carboxyl group. Lys19 and Arg67 line a positively charged groove, which favours binding of Asp over the neutral Asn. The ligand-binding cleft is of sufficient depth to accommodate a glutamate. This is the first structure of an ABC-type aspartate-binding protein, and explains the high affinity of the protein for aspartate and glutamate, and its much weaker binding of asparagine and glutamine. Stopped-flow fluorescence spectroscopy indicates a simple bimolecular mechanism of ligand binding, with high association rate constants. Sequence alignments and phylogenetic analyses revealed PEB1a homologues in some Gram-positive bacteria. The alignments suggest a more distant homology with GltI from Escherichia coli, a known glutamate and aspartate-binding protein, but Lys19 and Tyr156 are not conserved in GltI. Our results provide a structural basis for understanding both the solute transport and adhesin/virulence functions of PEB1a.
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Affiliation(s)
- Axel Müller
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW, UK
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11
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Leon-Kempis MDR, Guccione E, Mulholland F, Williamson MP, Kelly DJ. The Campylobacter jejuni PEB1a adhesin is an aspartate/glutamate-binding protein of an ABC transporter essential for microaerobic growth on dicarboxylic amino acids. Mol Microbiol 2006; 60:1262-75. [PMID: 16689801 DOI: 10.1111/j.1365-2958.2006.05168.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The PEB1a protein of the gastrointestinal pathogen Campylobacter jejuni mediates interactions with epithelial cells and is an important factor in host colonization. Cell fractionation and immunoblotting showed that PEB1a is most abundant in the periplasm of C. jejuni, and is detectable in the culture supernatant but not in the inner or outer membrane. The protein is homologous with periplasmic-binding proteins associated with ABC transporters and we show by fluorescence spectroscopy that purified recombinant PEB1a binds L-aspartate and L-glutamate with sub microM K(d) values. Binding of L-14C-aspartate or L-14C-glutamate was strongly out-competed by excess unlabelled aspartate or glutamate but only poorly by asparagine and glutamine. A mutant in the Cj0921c gene, encoding PEB1a, was completely unable to transport 5 microM L-14C-glutamate and showed a large reduction (approximately 20-fold) in the rate of L-14C-aspartate transport compared with the wild type. Although microaerobic growth of this mutant was little affected in complex media, growth on aspartate or glutamate in defined media was completely prevented, whereas growth with serine was similar to wild type. 1H-NMR analysis of the culture supernatants of the Cj0921c mutant showed some utilization of aspartate but not glutamate, consistent with the transport data. It is concluded that in addition to the established role of PEB1a as an adhesin, the PEB1 transport system plays a key role in the utilization of aspartate and glutamate, which may be important in vivo carbon sources for this pathogen.
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Affiliation(s)
- Maria del Rocio Leon-Kempis
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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12
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Okumoto S, Looger LL, Micheva KD, Reimer RJ, Smith SJ, Frommer WB. Detection of glutamate release from neurons by genetically encoded surface-displayed FRET nanosensors. Proc Natl Acad Sci U S A 2005; 102:8740-5. [PMID: 15939876 PMCID: PMC1143584 DOI: 10.1073/pnas.0503274102] [Citation(s) in RCA: 284] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Indexed: 11/18/2022] Open
Abstract
Glutamate is the predominant excitatory neurotransmitter in the mammalian brain. Once released, its rapid removal from the synaptic cleft is critical for preventing excitotoxicity and spillover to neighboring synapses. Despite consensus on the role of glutamate in normal and disease physiology, technical issues limit our understanding of its metabolism in intact cells. To monitor glutamate levels inside and at the surface of living cells, genetically encoded nanosensors were developed. The fluorescent indicator protein for glutamate (FLIPE) consists of the glutamate/aspartate binding protein ybeJ from Escherichia coli fused to two variants of the green fluorescent protein. Three sensors with lower affinities for glutamate were created by mutation of residues peristeric to the ybeJ binding pocket. In the presence of ligands, FLIPEs show a concentration-dependent decrease in FRET efficiency. When expressed on the surface of rat hippocampal neurons or PC12 cells, the sensors respond to extracellular glutamate with a reversible concentration-dependent decrease in FRET efficiency. Depolarization of neurons leads to a reduction in FRET efficiency corresponding to 300 nM glutamate at the cell surface. No change in FRET was observed when cells expressing sensors in the cytosol were superfused with up to 20 mM glutamate, consistent with a minimal contribution of glutamate uptake to cytosolic glutamate levels. The results demonstrate that FLIPE sensors can be used for real-time monitoring of glutamate metabolism in living cells, in tissues, or in intact organisms, providing tools for studying metabolism or for drug discovery.
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Affiliation(s)
- Sakiko Okumoto
- Department of Plant Biology, Carnegie Institution of Washington, 260 Panama Street, Stanford, CA 94305, USA
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13
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Reitzer L. Biosynthesis of Glutamate, Aspartate, Asparagine, L-Alanine, and D-Alanine. EcoSal Plus 2004; 1. [PMID: 26443364 DOI: 10.1128/ecosalplus.3.6.1.3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Indexed: 06/05/2023]
Abstract
Glutamate, aspartate, asparagine, L-alanine, and D-alanine are derived from intermediates of central metabolism, mostly the citric acid cycle, in one or two steps. While the pathways are short, the importance and complexity of the functions of these amino acids befit their proximity to central metabolism. Inorganic nitrogen (ammonia) is assimilated into glutamate, which is the major intracellular nitrogen donor. Glutamate is a precursor for arginine, glutamine, proline, and the polyamines. Glutamate degradation is also important for survival in acidic environments, and changes in glutamate concentration accompany changes in osmolarity. Aspartate is a precursor for asparagine, isoleucine, methionine, lysine, threonine, pyrimidines, NAD, and pantothenate; a nitrogen donor for arginine and purine synthesis; and an important metabolic effector controlling the interconversion of C3 and C4 intermediates and the activity of the DcuS-DcuR two-component system. Finally, L- and D-alanine are components of the peptide of peptidoglycan, and L-alanine is an effector of the leucine responsive regulatory protein and an inhibitor of glutamine synthetase (GS). This review summarizes the genes and enzymes of glutamate, aspartate, asparagine, L-alanine, and D-alanine synthesis and the regulators and environmental factors that control the expression of these genes. Glutamate dehydrogenase (GDH) deficient strains of E. coli, K. aerogenes, and S. enterica serovar Typhimurium grow normally in glucose containing (energy-rich) minimal medium but are at a competitive disadvantage in energy limited medium. Glutamate, aspartate, asparagine, L-alanine, and D-alanine have multiple transport systems.
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de Lorimier RM, Smith JJ, Dwyer MA, Looger LL, Sali KM, Paavola CD, Rizk SS, Sadigov S, Conrad DW, Loew L, Hellinga HW. Construction of a fluorescent biosensor family. Protein Sci 2002; 11:2655-75. [PMID: 12381848 PMCID: PMC2373719 DOI: 10.1110/ps.021860] [Citation(s) in RCA: 262] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Bacterial periplasmic binding proteins (bPBPs) are specific for a wide variety of small molecule ligands. bPBPs undergo a large, ligand-mediated conformational change that can be linked to reporter functions to monitor ligand concentrations. This mechanism provides the basis of a general system for engineering families of reagentless biosensors that share a common physical signal transduction functionality and detect many different analytes. We demonstrate the facility of designing optical biosensors based on fluorophore conjugates using 8 environmentally sensitive fluorophores and 11 bPBPs specific for diverse ligands, including sugars, amino acids, anions, cations, and dipeptides. Construction of reagentless fluorescent biosensors relies on identification of sites that undergo a local conformational change in concert with the global, ligand-mediated hinge-bending motion. Construction of cysteine mutations at these locations then permits site-specific coupling of environmentally sensitive fluorophores that report ligand binding as changes in fluorescence intensity. For 10 of the bPBPs presented in this study, the three-dimensional receptor structure was used to predict the location of reporter sites. In one case, a bPBP sensor specific for glutamic and aspartic acid was designed starting from genome sequence information and illustrates the potential for discovering novel binding functions in the microbial genosphere using bioinformatics.
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Affiliation(s)
- Robert M de Lorimier
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Reitzer L, Schneider BL. Metabolic context and possible physiological themes of sigma(54)-dependent genes in Escherichia coli. Microbiol Mol Biol Rev 2001; 65:422-44, table of contents. [PMID: 11528004 PMCID: PMC99035 DOI: 10.1128/mmbr.65.3.422-444.2001] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sigma(54) has several features that distinguish it from other sigma factors in Escherichia coli: it is not homologous to other sigma subunits, sigma(54)-dependent expression absolutely requires an activator, and the activator binding sites can be far from the transcription start site. A rationale for these properties has not been readily apparent, in part because of an inability to assign a common physiological function for sigma(54)-dependent genes. Surveys of sigma(54)-dependent genes from a variety of organisms suggest that the products of these genes are often involved in nitrogen assimilation; however, many are not. Such broad surveys inevitably remove the sigma(54)-dependent genes from a potentially coherent metabolic context. To address this concern, we consider the function and metabolic context of sigma(54)-dependent genes primarily from a single organism, Escherichia coli, in which a reasonably complete list of sigma(54)-dependent genes has been identified by computer analysis combined with a DNA microarray analysis of nitrogen limitation-induced genes. E. coli appears to have approximately 30 sigma(54)-dependent operons, and about half are involved in nitrogen assimilation and metabolism. A possible physiological relationship between sigma(54)-dependent genes may be based on the fact that nitrogen assimilation consumes energy and intermediates of central metabolism. The products of the sigma(54)-dependent genes that are not involved in nitrogen metabolism may prevent depletion of metabolites and energy resources in certain environments or partially neutralize adverse conditions. Such a relationship may limit the number of physiological themes of sigma(54)-dependent genes within a single organism and may partially account for the unique features of sigma(54) and sigma(54)-dependent gene expression.
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Affiliation(s)
- L Reitzer
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, TX 75083-0688, USA.
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Urbanowski ML, Stauffer LT, Stauffer GV. The gcvB gene encodes a small untranslated RNA involved in expression of the dipeptide and oligopeptide transport systems in Escherichia coli. Mol Microbiol 2000; 37:856-68. [PMID: 10972807 DOI: 10.1046/j.1365-2958.2000.02051.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Escherichia coli gcvB gene encodes a small RNA transcript that is not translated in vivo. Transcription from the gcvB promoter is activated by the GcvA protein and repressed by the GcvR protein, the transcriptional regulators of the gcvTHP operon encoding the enzymes of the glycine cleavage system. A strain carrying a chromosomal deletion of gcvB exhibits normal regulation of gcvTHP expression and glycine cleavage enzyme activity. However, this mutant has high constitutive synthesis of OppA and DppA, the periplasmic-binding protein components of the two major peptide transport systems normally repressed in cells growing in rich medium. The altered regulation of oppA and dppA was also demonstrated using oppA-phoA and dppA-lacZ gene fusions. Although the mechanism(s) involving gcvB in the repression of these two genes is not known, oppA regulation appears to be at the translational level, whereas dppA regulation occurs at the mRNA level.
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Affiliation(s)
- M L Urbanowski
- Department of Microbiology, University of Iowa, Iowa City 52242, USA
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Affiliation(s)
- G F Ames
- Department of Molecular and Cell Biology, University of California at Berkeley 94720
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Allison C, Lai HC, Gygi D, Hughes C. Cell differentiation of Proteus mirabilis is initiated by glutamine, a specific chemoattractant for swarming cells. Mol Microbiol 1993; 8:53-60. [PMID: 8497197 DOI: 10.1111/j.1365-2958.1993.tb01202.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Swarming by Proteus mirabilis involves differentiation of typical short vegetative rods into filamentous hyperflagellated swarm cells which undergo cycles of rapid and co-ordinated population migration across surfaces and exhibit high levels of virulence gene expression. By supplementing a minimal growth medium (MGM) unable to support swarming migration we identified a single amino acid, glutamine, as sufficient to signal initiation of cell differentiation and migration. Bacteria isolated from the migrating edge of colonies grown for 8 h with glutamine as the only amino acid were filamentous and synthesized the characteristic high levels of flagellin and haemolysin. In contrast, addition of the other 19 common amino acids (excluding glutamine) individually or in combination did not initiate differentiation even after 24 h, cells remaining typical vegetative rods with basal levels of haemolysin and flagellin. The glutamine analogue gamma-glutamyl hydroxamate (GH) inhibited swarming but not growth of P. mirabilis on glutamine MGM and transposon mutants defective in glutamine uptake retained their response to glutamine signalling and its inhibition by GH, suggesting that differentiation signalling by glutamine may be transduced independently of the cellular glutamine transport system. Levels of mRNA transcribed from the haemolysin (hpmA) and flagellin (fliC) genes were low in vegetative cells grown on MGM without glutamine or with glutamine and GH, but were specifically increased c. 40-fold during glutamine-dependent differentiation. In liquid glutamine-MGM cultures, differentiation to filamentous hyper-flagellated hyper-haemolytic swarm cells occurred early in the exponential phase of growth, and increased concomitantly with the concentration of glutamine from a 0.1 mM threshold up to 10 mM.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Allison
- Cambridge University Department of Pathology, UK
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Abstract
Antibodies against the purified bovine brain glutamate binding protein (GBP) were raised in rabbits. Both nonderivatized and dinitrobenzene-derivatized GBP produced strong immunological responses in rabbits. Using the enzyme-linked immunosorbent assay (ELISA), we have quantified the antibody production and determined the specificity of the antibodies. Bovine brain GBP and the analogous protein from rat brain interacted most strongly with the antibodies. A bacterial glutamate-aspartate binding protein, as well as the enzymes glutamate dehydrogenase (EC 1.4.1.3), glutamine synthetase (EC 6.3.1.2), and gamma-glutamyl transpeptidase (EC 2.3.2.2), showed little or no cross-reactivity with the anti-GBP antibodies. A crude bacterial glutamate decarboxylase (EC 4.1.1.15) preparation gave a small to moderate cross-reaction with the anti-GBP antibodies. The sensitivity of the ELISA assay and the specificity of the antibodies were such that GBP levels as low as 3-10 ng could be detected.
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Renaturation and identification of periplasmic proteins in two-dimensional gels of Escherichia coli. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33394-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Ahlem C, Huisman W, Neslund G, Dahms AS. Purification and properties of a periplasmic D-xylose-binding protein from Escherichia coli K-12. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)81053-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Abstract
The active transport of glutamine by Escherichia coli occurs via a single osmotic shock-sensitive transport system which is known to be dependent upon a periplasmic binding protein specific for glutamine. We obtained a mutant that had elevated levels of glutamine transport and overproduced the glutamine binding protein. From this strain many point mutants and deletion-carrying strains defective in glutamine transport were isolated by a variety of techniques. The genetic locus coding for the glutamine transport system, glnP, and the regulatory mutation which causes overproduction of the transport system were both shown to map at 17.7 min on the E. coli chromosome, and it was demonstrated that the glnP locus contains the structural gene for the glutamine binding protein. Evidence was also obtained that the glutamine transport system, by an unknown mechanism, plays a direct role in the catabolism of glutamate and, hence, of glutamine and proline as well.
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Kustu SG, McFarland NC, Hui SP, Esmon B, Ames GF. Nitrogen control of Salmonella typhimurium: co-regulation of synthesis of glutamine synthetase and amino acid transport systems. J Bacteriol 1979; 138:218-34. [PMID: 35521 PMCID: PMC218260 DOI: 10.1128/jb.138.1.218-234.1979] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nitrogen control in Salmonella typhimurium is not limited to glutamine synthetase but affects, in addition, transport systems for histidine, glutamine, lysine-arginine-ornithine, and glutamate-aspartate. Synthesis of both glutamine synthetase and transport proteins is elevated by limitation of nitrogen in the growth medium or as a result of nitrogen (N)-regulatory mutations. Increases in the amounts of these proteins were demonstrated by direct measurements of their activities, by immunological techniques, and by visual inspection of cell fractions after gel electrophoresis. The N-regulatory mutations are closely linked on the chromosome to the structural gene for glutamine synthetase, glnA: we discuss the possibility that they lie in a regulatory gene, glnR, which is distinct from glnA. Increases in amino acid transport in N-regulatory mutant strains were indicated by increased activity in direct transport assays, improved growth on substrates of the transport systems, and increased sensitivity to inhibitory analogs that are trnasported by these systems. Mutations to loss of function of individual transport components (hisJ, hisP, glnH, argT) were introduced into N-regulatory mutant strains to determine the roles of these components in the phenotype and transport behavior of the strains. The structural gene for the periplasmic glutamine-binding protein, glnH, was identified, as was a gene argT that probably encodes the structure of the lysine-arginine-ornithine-binding protein. Genes encoding the structures of the histidine- and glutamine-binding proteins are not linked to glnA or to each other by P22-mediated transduction; thus, nitrogen control is exerted on several unlinked genes.
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Resolution of the multiplicity of the glutamate and aspartate transport systems of Escherichia coli. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(17)38344-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Kahane S, Metzer E, Halpern YS. 1. Membrane vesicles of Escherichia coli K-12 CS7, a strain gentically derepressed for glutamate permease, maintain low aspartate transport activity, like that of prep. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 66:583-9. [PMID: 782886 DOI: 10.1111/j.1432-1033.1976.tb10585.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. Membrane vesicles of Escherichia coli K-12 CS7, a strain gentically derepressed for glutamate permease, maintain low aspartate transport activity, like that of preparations of the wild-type parent. Growth of the parent CS101 on aspartate as the source of carnon or nitrogen results in derepression of both asparatate and glytamate transport. Growth of strain CS7 on aspartate derepresses aspartate transport to the same extent as in strains CS101, but only slightly increases the derepressed level of glutamate transport activity. 2. The affinity of the membrane transport system for glutamate is enhanced by sodium, while that for asparate is not. 3. Although the affinities for glutamate (23 muM) and aspartate (12 muM) are similar, aspartate does not inhibit glutamate transport, while glutamate competitively inhibits aspartate transport. 4. Aspartate transport, but not glutamate transport, is competitively inhibited by C4 dicarboxylic acids, whereas 2-oxoglutarate competitively inhibits glutamate transport, but not aspartate transport. 5. Competitive inhibition of L-aspartate transport by L-glutamate and by the 5-methyl ester of L-glutamate is abolished in the presence of 2-oxoglutarate. However, 2-oxoglutarate does not affect the competitive inhibition of L-aspartate transport by D-aspartate and by DL-threo-3-hydroxyaspartate. The relationship between the two dicarboxylic amino acid transport systems and the spatial characteristics of the aspartate carrier are discussed in the light of these findings.
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Willis RC, Seegmiller JE. A filtration assay specific for the determination of small quantities of L-glutamine. Anal Biochem 1976; 72:66-77. [PMID: 782289 DOI: 10.1016/0003-2697(76)90507-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
The recent studies have clearly established two types of active transport systems. One type is membrane-bound and can be observed in membrane vesicles and the other type is osmotic-shock-sensitive and requires binding proteins to produce active transport. It appears that the membrane-bound systems derive cellular energy from the energy-rich membrane state which can be formed from respiration or ATP-hydrolysis, while the binding protein systems are more directly coupled to phosphate bond energy derived from glycolysis or oxidative phosphorylation. The following conclusions concerning the role of the binding proteins are offered: 1. The binding proteins are present in relatively large amounts (approximately 10(-6) or 10%-5) M) and appear to reside in the periplasmic space. 2. They do not appear to be involved in solute translocation steps, although they cantain a second binding site that could interact with membrane components. 3. The binding proteins appear to increase the affinity of the transport system for the solute by interacting with a membrane component. This may substrate for the membrane transport system.
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A transport system for phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate in Salmonella typhimurium. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41282-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Willis RC, Furlong CE. Interactions of a glutamate-aspartate binding protein with the glutamate transport system of Escherichia coli. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41640-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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