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Jasinska W, Dindo M, Cordoba SMC, Serohijos AWR, Laurino P, Brotman Y, Bershtein S. Non-consecutive enzyme interactions within TCA cycle supramolecular assembly regulate carbon-nitrogen metabolism. Nat Commun 2024; 15:5285. [PMID: 38902266 PMCID: PMC11189929 DOI: 10.1038/s41467-024-49646-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 06/14/2024] [Indexed: 06/22/2024] Open
Abstract
Enzymes of the central metabolism tend to assemble into transient supramolecular complexes. However, the functional significance of the interactions, particularly between enzymes catalyzing non-consecutive reactions, remains unclear. Here, by co-localizing two non-consecutive enzymes of the TCA cycle from Bacillus subtilis, malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD), in phase separated droplets we show that MDH-ICD interaction leads to enzyme agglomeration with a concomitant enhancement of ICD catalytic rate and an apparent sequestration of its reaction product, 2-oxoglutarate. Theory demonstrates that MDH-mediated clustering of ICD molecules explains the observed phenomena. In vivo analyses reveal that MDH overexpression leads to accumulation of 2-oxoglutarate and reduction of fluxes flowing through both the catabolic and anabolic branches of the carbon-nitrogen intersection occupied by 2-oxoglutarate, resulting in impeded ammonium assimilation and reduced biomass production. Our findings suggest that the MDH-ICD interaction is an important coordinator of carbon-nitrogen metabolism.
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Affiliation(s)
- Weronika Jasinska
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Mirco Dindo
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Department of Medicine and Surgery, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
| | - Sandra M C Cordoba
- Max-Planck-Institut fur Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Adrian W R Serohijos
- Departement de Biochimie, Universite de Montreal, Quebec, Canada
- Centre Robert-Cedergren en Bio-informatique et Genomique, Universite de Montreal, Quebec, Canada
| | - Paola Laurino
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
- Institute for Protein Research, Osaka University, Suita, Japan.
| | - Yariv Brotman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | - Shimon Bershtein
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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2
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Salinas P, Bibak S, Cantos R, Tremiño L, Jerez C, Mata-Balaguer T, Contreras A. Studies on the PII-PipX-NtcA Regulatory Axis of Cyanobacteria Provide Novel Insights into the Advantages and Limitations of Two-Hybrid Systems for Protein Interactions. Int J Mol Sci 2024; 25:5429. [PMID: 38791467 PMCID: PMC11121479 DOI: 10.3390/ijms25105429] [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: 04/05/2024] [Revised: 05/11/2024] [Accepted: 05/12/2024] [Indexed: 05/26/2024] Open
Abstract
Yeast two-hybrid approaches, which are based on fusion proteins that must co-localise to the nucleus to reconstitute the transcriptional activity of GAL4, have greatly contributed to our understanding of the nitrogen interaction network of cyanobacteria, the main hubs of which are the trimeric PII and the monomeric PipX regulators. The bacterial two-hybrid system, based on the reconstitution in the E. coli cytoplasm of the adenylate cyclase of Bordetella pertussis, should provide a relatively faster and presumably more physiological assay for cyanobacterial proteins than the yeast system. Here, we used the bacterial two-hybrid system to gain additional insights into the cyanobacterial PipX interaction network while simultaneously assessing the advantages and limitations of the two most popular two-hybrid systems. A comprehensive mutational analysis of PipX and bacterial two-hybrid assays were performed to compare the outcomes between yeast and bacterial systems. We detected interactions that were previously recorded in the yeast two-hybrid system as negative, as well as a "false positive", the self-interaction of PipX, which is rather an indirect interaction that is dependent on PII homologues from the E. coli host, a result confirmed by Western blot analysis with relevant PipX variants. This is, to our knowledge, the first report of the molecular basis of a false positive in the bacterial two-hybrid system.
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Affiliation(s)
| | | | | | | | | | | | - Asunción Contreras
- Departamento. de Fisiología, Genética y Microbiología, Universidad de Alicante, 03690 San Vicente del Raspeig, Spain; (P.S.); (S.B.); (R.C.); (L.T.); (C.J.); (T.M.-B.)
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3
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Niu S, Liu F, Wang Y, Rao B, Wang Y. A Study on the Efficient Preparation of α-Ketoglutarate with L-Glutamate Oxidase. Molecules 2024; 29:1861. [PMID: 38675681 PMCID: PMC11055115 DOI: 10.3390/molecules29081861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/09/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Alpha-ketoglutaric acid (α-KG), as an intermediate product of the tricarboxylic acid cycle, plays a crucial role in peptide and amino acid synthesis. In order to reduce costs and improve efficiency in the oxidative production of α-ketoglutaric acid, this study successfully synthesized and expressed L-glutamate oxidase (LGOXStr) from Streptomyces viridosporus R111 and catalase (KatGEsc) from Escherichia coli H736. Two immobilization methods and the conditions for one-step whole-cell catalysis of α-ketoglutaric acid were investigated. α-Ketoglutaric acid has broad applications in the pharmaceutical, food, and chemical industries. The specific research results are as follows: (1) By fusing the sfGFP tag, L-glutamate oxidase (LGOXStr r) and catalase (KatGEsc) were successfully anchored to the outer membrane of Escherichia coli cells, achieving one-step whole-cell catalysis of α-ketoglutaric acid with a conversion efficiency of up to 75%. (2) Through the co-immobilization of LGOXStr and KatGEsc, optimization of the preparation parameters of immobilized cells, and exploration of the immobilization method using E.coli@ZIF-8, immobilized cells with conversion rates of over 60% were obtained even after 10 cycles of reuse. Under the optimal conditions, the production rate of α-ketoglutaric acid reached 96.7% in a 12 h reaction, which is 1.1 times that of E. coli@SA and 1.29 times that of free cells.
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Affiliation(s)
- Shuhui Niu
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, China; (S.N.)
- State Key Laboratory of Biocatalysis and Enzyme, Engineering Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Biology Faculty, Hubei University, Wuhan 430062, China
| | - Fang Liu
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, China; (S.N.)
| | - Yaping Wang
- State Key Laboratory of Biocatalysis and Enzyme, Engineering Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, Biology Faculty, Hubei University, Wuhan 430062, China
| | - Ben Rao
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, China; (S.N.)
| | - Yueying Wang
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, China; (S.N.)
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4
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Miyakoshi M. Multilayered regulation of amino acid metabolism in Escherichia coli. Curr Opin Microbiol 2024; 77:102406. [PMID: 38061078 DOI: 10.1016/j.mib.2023.102406] [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: 09/06/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 02/12/2024]
Abstract
Amino acid metabolism in Escherichia coli has long been studied and has established the basis for regulatory mechanisms at the transcriptional, posttranscriptional, and posttranslational levels. In addition to the classical signal transduction cascade involving posttranslational modifications (PTMs), novel PTMs in the two primary nitrogen assimilation pathways have recently been uncovered. The regulon of the master transcriptional regulator NtrC is further expanded by a small RNA derived from the 3´UTR of glutamine synthetase mRNA, which coordinates central carbon and nitrogen metabolism. Furthermore, recent advances in sequencing technologies have revealed the global regulatory networks of transcriptional and posttranscriptional regulators, Lrp and GcvB. This review provides an update of the multilayered and interconnected regulatory networks governing amino acid metabolism in E. coli.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Infection Biology, Institute of Medicine, University of Tsukuba, 305-8575 Ibaraki, Japan.
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5
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Fang F, Xue Y, Xu X, Fang D, Liu W, Zhong Y, Han J, Li Y, Tao Q, Lu R, Ma C, Kumar A, Wang D. L-glutamine protects against enterohemorrhagic Escherichia coli infection by inhibiting bacterial virulence and enhancing host defense concurrently. Microbiol Spectr 2023; 11:e0097523. [PMID: 37815335 PMCID: PMC10714755 DOI: 10.1128/spectrum.00975-23] [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: 03/07/2023] [Accepted: 08/24/2023] [Indexed: 10/11/2023] Open
Abstract
IMPORTANCE The type 3 secretion system (T3SS) was obtained in many Gram-negative bacterial pathogens, and it is crucial for their pathogenesis. Environmental signals were found to be involved in the expression regulation of T3SS, which was vital for successful bacterial infection in the host. Here, we discovered that L-glutamine (Gln), the most abundant amino acid in the human body, could repress enterohemorrhagic Escherichia coli (EHEC) T3SS expression via nitrogen metabolism and therefore had potential as an antivirulence agent. Our in vitro and in vivo evidence demonstrated that Gln could decline EHEC infection by attenuating bacterial virulence and enhancing host defense simultaneously. We repurpose Gln as a potential treatment for EHEC infection accordingly.
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Affiliation(s)
- Fang Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunxin Xue
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Xuefang Xu
- State Key Laboratory of Infectious Disease Prevention and Control and National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China
| | - Dingli Fang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Weijia Liu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Ying Zhong
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Jinping Han
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yunhe Li
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Qian Tao
- Department of Pathology, Women and Children's Hospital, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, Xiamen University, Xiamen, Fujian Province, China
| | - Rong Lu
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Cong Ma
- Department of Nephrology, Lishan Hospital, Anshan Central Hospital, Anshan, Liaoning Province, China
| | | | - Dai Wang
- Department of Laboratory Medicine, Xiamen Key Laboratory of Perinatal-Neonatal Infection, Women and Children's Hospital, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedical Laboratory, School of Public Health and School of Medicine, Xiamen University, Xiamen, Fujian Province, China
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6
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North H, McLaughlin M, Fiebig A, Crosson S. The Caulobacter NtrB-NtrC two-component system bridges nitrogen assimilation and cell development. J Bacteriol 2023; 205:e0018123. [PMID: 37791753 PMCID: PMC10601693 DOI: 10.1128/jb.00181-23] [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: 06/07/2023] [Accepted: 09/03/2023] [Indexed: 10/05/2023] Open
Abstract
A suite of molecular sensory systems enables Caulobacter to control growth, development, and reproduction in response to levels of essential elements. The bacterial enhancer-binding protein (bEBP) NtrC and its cognate sensor histidine kinase, NtrB, are key regulators of nitrogen assimilation in many bacteria, but their roles in Caulobacter metabolism and development are not well defined. Notably, Caulobacter NtrC is an unconventional bEBP that lacks the σ54-interacting loop commonly known as the GAFTGA motif. Here we show that deletion of Caulobacter crescentus ntrC slows cell growth in complex medium and that ntrB and ntrC are essential when ammonium is the sole nitrogen source due to their requirement for glutamine synthetase expression. Random transposition of a conserved IS3-family mobile genetic element frequently rescued the growth defect of ntrC mutant strains by restoring transcription of the glnBA operon, revealing a possible role for IS3 transposition in shaping the evolution of Caulobacter populations during nutrient limitation. We further identified dozens of direct NtrC-binding sites on the C. crescentus chromosome, with a large fraction located near genes involved in polysaccharide biosynthesis. The majority of binding sites align with those of the essential nucleoid-associated protein, GapR, or the cell cycle regulator, MucR1. NtrC is therefore predicted to directly impact the regulation of cell cycle and cell development. Indeed, loss of NtrC function led to elongated polar stalks and elevated synthesis of cell envelope polysaccharides. This study establishes regulatory connections between NtrC, nitrogen metabolism, polar morphogenesis, and envelope polysaccharide synthesis in Caulobacter. IMPORTANCE Bacteria balance cellular processes with the availability of nutrients in their environment. The NtrB-NtrC two-component signaling system is responsible for controlling nitrogen assimilation in many bacteria. We have characterized the effect of ntrB and ntrC deletion on Caulobacter growth and development and uncovered a role for spontaneous IS element transposition in the rescue of transcriptional and nutritional deficiencies caused by ntrC mutation. We further defined the regulon of Caulobacter NtrC, a bacterial enhancer-binding protein, and demonstrate that it shares specific binding sites with essential proteins involved in cell cycle regulation and chromosome organization. Our work provides a comprehensive view of transcriptional regulation mediated by a distinctive NtrC protein, establishing its connection to nitrogen assimilation and developmental processes in Caulobacter.
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Affiliation(s)
- Hunter North
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Maeve McLaughlin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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7
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North H, McLaughlin M, Fiebig A, Crosson S. The Caulobacter NtrB-NtrC two-component system bridges nitrogen assimilation and cell development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543975. [PMID: 37333394 PMCID: PMC10274813 DOI: 10.1101/2023.06.06.543975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
A suite of molecular sensory systems enables Caulobacter to control growth, development, and reproduction in response to levels of essential elements. The bacterial enhancer binding protein (bEBP) NtrC, and its cognate sensor histidine kinase NtrB, are key regulators of nitrogen assimilation in many bacteria, but their roles in Caulobacter metabolism and development are not well defined. Notably, Caulobacter NtrC is an unconventional bEBP that lacks the σ54-interacting loop commonly known as the GAFTGA motif. Here we show that deletion of C. crescentus ntrC slows cell growth in complex medium, and that ntrB and ntrC are essential when ammonium is the sole nitrogen source due to their requirement for glutamine synthetase (glnA) expression. Random transposition of a conserved IS3-family mobile genetic element frequently rescued the growth defect of ntrC mutant strains by restoring transcription of the glnBA operon, revealing a possible role for IS3 transposition in shaping the evolution of Caulobacter populations during nutrient limitation. We further identified dozens of direct NtrC binding sites on the C. crescentus chromosome, with a large fraction located near genes involved in polysaccharide biosynthesis. The majority of binding sites align with those of the essential nucleoid associated protein, GapR, or the cell cycle regulator, MucR1. NtrC is therefore predicted to directly impact the regulation of cell cycle and cell development. Indeed, loss of NtrC function led to elongated polar stalks and elevated synthesis of cell envelope polysaccharides. This study establishes regulatory connections between NtrC, nitrogen metabolism, polar morphogenesis, and envelope polysaccharide synthesis in Caulobacter .
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Affiliation(s)
- Hunter North
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Maeve McLaughlin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
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8
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Sun Y, Zhang Y, Zhao T, Luan Y, Wang Y, Yang C, Shen B, Huang X, Li G, Zhao S, Zhao G, Wang Q. Acetylation coordinates the crosstalk between carbon metabolism and ammonium assimilation in Salmonella enterica. EMBO J 2023; 42:e112333. [PMID: 37183585 PMCID: PMC10308350 DOI: 10.15252/embj.2022112333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/21/2023] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Enteric bacteria use up to 15% of their cellular energy for ammonium assimilation via glutamine synthetase (GS)/glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) in response to varying ammonium availability. However, the sensory mechanisms for effective and appropriate coordination between carbon metabolism and ammonium assimilation have not been fully elucidated. Here, we report that in Salmonella enterica, carbon metabolism coordinates the activities of GS/GDH via functionally reversible protein lysine acetylation. Glucose promotes Pat acetyltransferase-mediated acetylation and activation of adenylylated GS. Simultaneously, glucose induces GDH acetylation to inactivate the enzyme by impeding its catalytic centre, which is reversed upon GDH deacetylation by deacetylase CobB. Molecular dynamics (MD) simulations indicate that adenylylation is required for acetylation-dependent activation of GS. We show that acetylation and deacetylation occur within minutes of "glucose shock" to promptly adapt to ammonium/carbon variation and finely balance glutamine/glutamate synthesis. Finally, in a mouse infection model, reduced S. enterica growth caused by the expression of adenylylation-mimetic GS is rescued by acetylation-mimicking mutations. Thus, glucose-driven acetylation integrates signals from ammonium assimilation and carbon metabolism to fine-tune bacterial growth control.
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Affiliation(s)
- Yunwei Sun
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yuebin Zhang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Tingting Zhao
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Yi Luan
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
| | - Ying Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Chen Yang
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Bo Shen
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xi Huang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina
| | - Shimin Zhao
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Collaborative Innovation Center for Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Guo‐ping Zhao
- CAS‐Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
- State Key Lab of Genetic Engineering & Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Department of Microbiology and Microbial Engineering, School of Life SciencesFudan UniversityShanghaiChina
- Shanghai‐MOST Key Laboratory of Disease and Health GenomicsChinese National Human Genome Center at ShanghaiShanghaiChina
- Department of Microbiology and Li KaShing Institute of Health SciencesThe Chinese University of Hong Kong, Prince of Wales HospitalShatin, New Territories, Hong Kong SARChina
| | - Qijun Wang
- Department of Gastroenterology of Ruijin Hospital, Shanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
- Department of Pharmacology, Vascular Biology and Therapeutic ProgramYale University School of MedicineNew HavenCTUSA
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9
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Wicke D, Meißner J, Warneke R, Elfmann C, Stülke J. Understudied proteins and understudied functions in the model bacterium Bacillus subtilis-A major challenge in current research. Mol Microbiol 2023. [PMID: 36882621 DOI: 10.1111/mmi.15053] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/09/2023]
Abstract
Model organisms such as the Gram-positive bacterium Bacillus subtilis have been studied intensively for decades. However, even for model organisms, no function has been identified for about one fourth of all proteins. It has recently been realized that such understudied proteins as well as poorly studied functions set a limitation to our understanding of the requirements for cellular life, and the Understudied Proteins Initiative has been launched. Of poorly studied proteins, those that are strongly expressed are likely to be important to the cell and should therefore be considered high priority in further studies. Since the functional analysis of unknown proteins can be extremely laborious, a minimal knowledge is required prior to targeted functional studies. In this review, we discuss strategies to obtain such a minimal annotation, for example, from global interaction, expression, or localization studies. We present a set of 41 highly expressed and poorly studied proteins of B. subtilis. Several of these proteins are thought or known to bind RNA and/or the ribosome, some may control the metabolism of B. subtilis, and another subset of particularly small proteins may act as regulatory elements to control the expression of downstream genes. Moreover, we discuss the challenges of poorly studied functions with a focus on RNA-binding proteins, amino acid transport, and the control of metabolic homeostasis. The identification of the functions of the selected proteins not only will strongly advance our knowledge on B. subtilis, but also on other organisms since many of the proteins are conserved in many groups of bacteria.
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Affiliation(s)
- Dennis Wicke
- Department of General Microbiology, Georg-August-University Göttingen, GZMB, Göttingen, Germany
| | - Janek Meißner
- Department of General Microbiology, Georg-August-University Göttingen, GZMB, Göttingen, Germany
| | - Robert Warneke
- Department of General Microbiology, Georg-August-University Göttingen, GZMB, Göttingen, Germany
| | - Christoph Elfmann
- Department of General Microbiology, Georg-August-University Göttingen, GZMB, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Georg-August-University Göttingen, GZMB, Göttingen, Germany
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10
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Martin Del Campo JS, Rigsbee J, Bueno Batista M, Mus F, Rubio LM, Einsle O, Peters JW, Dixon R, Dean DR, Dos Santos PC. Overview of physiological, biochemical, and regulatory aspects of nitrogen fixation in Azotobacter vinelandii. Crit Rev Biochem Mol Biol 2023; 57:492-538. [PMID: 36877487 DOI: 10.1080/10409238.2023.2181309] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Understanding how Nature accomplishes the reduction of inert nitrogen gas to form metabolically tractable ammonia at ambient temperature and pressure has challenged scientists for more than a century. Such an understanding is a key aspect toward accomplishing the transfer of the genetic determinants of biological nitrogen fixation to crop plants as well as for the development of improved synthetic catalysts based on the biological mechanism. Over the past 30 years, the free-living nitrogen-fixing bacterium Azotobacter vinelandii emerged as a preferred model organism for mechanistic, structural, genetic, and physiological studies aimed at understanding biological nitrogen fixation. This review provides a contemporary overview of these studies and places them within the context of their historical development.
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Affiliation(s)
| | - Jack Rigsbee
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | | | - Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Luis M Rubio
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Pozuelo de Alarcón, Spain
| | - Oliver Einsle
- Department of Biochemistry, University of Freiburg, Freiburg, Germany
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Dennis R Dean
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
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11
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Liu X, Reinbold R, Liu S, Herold RA, Rabe P, Duclos S, Yadav RB, Abboud MI, Thieffine S, Armstrong FA, Brewitz L, Schofield CJ. Natural and synthetic 2-oxoglutarate derivatives are substrates for oncogenic variants of human isocitrate dehydrogenase 1 and 2. J Biol Chem 2023; 299:102873. [PMID: 36621625 PMCID: PMC9939733 DOI: 10.1016/j.jbc.2023.102873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/07/2023] Open
Abstract
Variants of isocitrate dehydrogenase (IDH) 1 and 2 (IDH1/2) alter metabolism in cancer cells by catalyzing the NADPH-dependent reduction of 2-oxoglutarate (2OG) to (2R)-hydroxyglutarate. However, it is unclear how derivatives of 2OG can affect cancer cell metabolism. Here, we used synthetic C3- and C4-alkylated 2OG derivatives to investigate the substrate selectivities of the most common cancer-associated IDH1 variant (R132H IDH1), of two cancer-associated IDH2 variants (R172K IDH2, R140Q IDH2), and of WT IDH1/2. Absorbance-based, NMR, and electrochemical assays were employed to monitor WT IDH1/2 and IDH1/2 variant-catalyzed 2OG derivative turnover in the presence and absence of 2OG. Our results reveal that 2OG derivatives can serve as substrates of the investigated IDH1/2 variants, but not of WT IDH1/2, and have the potential to act as 2OG-competitive inhibitors. Kinetic parameters reveal that some 2OG derivatives, including the natural product 3-methyl-2OG, are equally or even more efficient IDH1/2 variant substrates than 2OG. Furthermore, NMR and mass spectrometry studies confirmed IDH1/2 variant-catalyzed production of alcohols in the cases of the 3-methyl-, 3-butyl-, and 3-benzyl-substituted 2OG derivatives; a crystal structure of 3-butyl-2OG with an IDH1 variant (R132C/S280F IDH1) reveals active site binding. The combined results highlight the potential for (i) IDH1/2 variant-catalyzed reduction of 2-oxoacids other than 2OG in cells, (ii) modulation of IDH1/2 variant activity by 2-oxoacid natural products, including some present in common foods, (iii) inhibition of IDH1/2 variants via active site binding rather than the established allosteric mode of inhibition, and (iv) possible use of IDH1/2 variants as biocatalysts.
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Affiliation(s)
- Xiao Liu
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | - Raphael Reinbold
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | - Shuang Liu
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | - Ryan A Herold
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Patrick Rabe
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | | | | | - Martine I Abboud
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | | | - Fraser A Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Lennart Brewitz
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom.
| | - Christopher J Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom.
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12
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Confirmation of Glucose Transporters through Targeted Mutagenesis and Transcriptional Analysis in Clostridium acetobutylicum. FERMENTATION 2023. [DOI: 10.3390/fermentation9010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The solvent-producing bacterium Clostridium acetobutylicum is able to grow on a variety of carbohydrates. The main hexose transport system is the phosphoenolpyruvate-dependent phosphotransferase system (PTS). When the gene glcG that encodes the glucose transporter was inactivated, the resulting mutant glcG::int(1224) grew as well as the wild type, yet its glucose consumption was reduced by 17% in a batch fermentation. Transcriptomics analysis of the phosphate-limited continuous cultures showed that the cellobiose transporter GlcCE was highly up-regulated in the mutant glcG::int(1224). The glcCE mutation did not affect growth and even consumed slightly more glucose during solventogenesis growth compared to wild type, indicating that GlcG is the primary glucose-specific PTS. Poor growth of the double mutant glcG::int(1224)-glcCE::int(193) further revealed that GlcCE was the secondary glucose PTS and that there must be other PTSs capable of glucose uptake. The observations obtained in this study provided a promising foundation to understand glucose transport in C. acetobutylicum.
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13
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Harten T, Nimzyk R, Gawlick VEA, Reinhold-Hurek B. Elucidation of Essential Genes and Mutant Fitness during Adaptation toward Nitrogen Fixation Conditions in the Endophyte Azoarcus olearius BH72 Revealed by Tn-Seq. Microbiol Spectr 2022; 10:e0216222. [PMID: 36416558 PMCID: PMC9769520 DOI: 10.1128/spectrum.02162-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/05/2022] [Indexed: 11/24/2022] Open
Abstract
Azoarcus olearius BH72 is a diazotrophic model endophyte that contributes fixed nitrogen to its host plant, Kallar grass, and expresses nitrogenase genes endophytically. Despite extensive studies on biological nitrogen fixation (BNF) of diazotrophic endophytes, little is known about global genetic players involved in survival under respective physiological conditions. Here, we report a global genomic screen for putatively essential genes of A. olearius employing Tn5 transposon mutagenesis with a modified transposon combined with high-throughput sequencing (Tn-Seq). A large Tn5 master library of ~6 × 105 insertion mutants of strain BH72 was obtained. Next-generation sequencing identified 183,437 unique insertion sites into the 4,376,040-bp genome, displaying one insertion every 24 bp on average. Applying stringent criteria, we describe 616 genes as putatively essential for growth on rich medium. COG (Clusters of Orthologous Groups) assignment of the 564 identified protein-coding genes revealed enrichment of genes related to core cellular functions and cell viability. To mimic gradual adaptations toward BNF conditions, the Tn5 mutant library was grown aerobically in synthetic medium or microaerobically on either combined or atmospheric nitrogen. Enrichment and depletion analysis of Tn5 mutants not only demonstrated the role of BNF- and metabolism-related proteins but also revealed that, strikingly, many genes relevant for plant-microbe interactions decrease bacterial competitiveness in pure culture, such type IV pilus- and bacterial envelope-associated genes. IMPORTANCE A constantly growing world population and the daunting challenge of climate change demand new strategies in agricultural crop production. Intensive usage of chemical fertilizers, overloading the world's fields with organic input, threaten terrestrial and marine ecosystems as well as human health. Long overlooked, the beneficial interaction of endophytic bacteria and grasses has attracted ever-growing interest in research in the last decade. Capable of biological nitrogen fixation, diazotrophic endophytes not only provide a valuable source of combined nitrogen but also are known for diverse plant growth-promoting effects, thereby contributing to plant productivity. Elucidation of an essential gene set for a prominent model endophyte such as A. olearius BH72 provides us with powerful insights into its basic lifestyle. Knowledge about genes detrimental or advantageous under defined physiological conditions may point out a way of manipulating key steps in the bacterium's lifestyle and plant interaction toward a more sustainable agriculture.
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Affiliation(s)
- Theresa Harten
- University of Bremen, Faculty of Biology and Chemistry, CBIB Center for Biomolecular Interactions, Department of Microbe-Plant Interactions, Bremen, Germany
| | - Rolf Nimzyk
- University of Bremen, Faculty of Biology and Chemistry, CBIB Center for Biomolecular Interactions, Department of Microbe-Plant Interactions, Bremen, Germany
- University of Bremen, Faculty of Biology and Chemistry, CBIB Center for Biomolecular Interactions, Nucleic Acid Analysis Facility (NAA), Bremen, Germany
| | - Vivian E. A. Gawlick
- University of Bremen, Faculty of Biology and Chemistry, CBIB Center for Biomolecular Interactions, Department of Microbe-Plant Interactions, Bremen, Germany
| | - Barbara Reinhold-Hurek
- University of Bremen, Faculty of Biology and Chemistry, CBIB Center for Biomolecular Interactions, Department of Microbe-Plant Interactions, Bremen, Germany
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14
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Iskhakova ZI, Zhuravleva DE, Heim C, Hartmann MD, Laykov AV, Forchhammer K, Kayumov AR. PotN represents a novel energy‐state sensing PII subfamily, occurring in firmicutes. FEBS J 2022; 289:5305-5321. [DOI: 10.1111/febs.16431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 02/19/2022] [Accepted: 03/10/2022] [Indexed: 01/19/2023]
Affiliation(s)
| | | | - Christopher Heim
- Department of Protein Evolution Max Planck Institute for Developmental Biology Tübingen Germany
| | - Marcus D. Hartmann
- Department of Protein Evolution Max Planck Institute for Developmental Biology Tübingen Germany
| | | | - Karl Forchhammer
- Institut für Mikrobiologie Eberhard‐Karls‐Universität Tübingen Germany
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15
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Effect of pII key nitrogen regulatory gene on strain growth and butenyl-spinosyn biosynthesis in Saccharopolyspora pogona. Appl Microbiol Biotechnol 2022; 106:3081-3091. [PMID: 35376972 DOI: 10.1007/s00253-022-11902-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 03/24/2022] [Accepted: 03/26/2022] [Indexed: 11/02/2022]
Abstract
PII signal transduction proteins are widely found in bacteria and plant chloroplast, and play a central role in nitrogen metabolism regulation, which interact with many key proteins in metabolic pathways to regulate carbon/nitrogen balance by sensing changes in concentrations of cell-mediated indicators such as α-ketoglutarate. In this study, the knockout strain Saccharopolyspora pogona-ΔpII and overexpression strain S. pogona-pII were constructed using CRISPR/Cas9 technology and the shuttle vector POJ260, respectively, to investigate the effects on the growth and secondary metabolite biosynthesis of S. pogona. Growth curve, electron microscopy, and spore germination experiments were performed, and it was found that the deletion of the pII gene inhibited the growth to a certain extent in the mutant. HPLC analysis showed that the yield of butenyl-spinosyn in the S. pogona-pII strain increased to 245% than that in the wild-type strain while that in S. pogona-ΔpII decreased by approximately 51%. This result showed that the pII gene can promote the growth and butenyl-spinosyn biosynthesis of S. pogona. This research first investigated PII nitrogen metabolism regulators in S. pogona, providing significant scientific evidence and a research basis for elucidating the mechanism by which these factors regulate the growth of S. pogona, optimizing the synthesis network of butenyl-spinosyn and constructing a strain with a high butenyl-spinosyn yield. KEY POINTS: • pII key nitrogen regulatory gene deletion can inhibit the growth and development of S. pogona. • Overexpressed pII gene can significantly promote the butenyl-spinosyn biosynthesis. • pII gene can affect the amino acid circulation and the accumulation of butenyl-spinosyn precursors in S. pogona.
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16
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New views on PII signaling: from nitrogen sensing to global metabolic control. Trends Microbiol 2022; 30:722-735. [DOI: 10.1016/j.tim.2021.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 11/20/2022]
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17
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Wan X, Brynildsen MP. Robustness of nitric oxide detoxification to nitrogen starvation in Escherichia coli requires RelA. Free Radic Biol Med 2021; 176:286-297. [PMID: 34624482 DOI: 10.1016/j.freeradbiomed.2021.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/04/2021] [Indexed: 01/18/2023]
Abstract
Reactive nitrogen species and nutrient deprivation are two elements of the immune response used to eliminate pathogens within phagosomes. Concomitantly, pathogenic bacteria have evolved defense systems to cope with phagosomal stressors, which include enzymes that detoxify nitric oxide (•NO) and respond to nutrient scarcity. A deeper understanding of how those defense systems are deployed under adverse conditions that contain key elements of phagosomes will facilitate targeting of those systems for therapeutic purposes. Here we investigated how Escherichia coli detoxifies •NO in the absence of useable nitrogen, because nitrogen availability is limited in phagosomes due to the removal of nitrogenous compounds (e.g., amino acids). We hypothesized that nitrogen starvation would impair •NO detoxification by E. coli because it depresses translation rates and the main E. coli defense enzyme, Hmp, is synthesized in response to •NO. However, we found that E. coli detoxifies •NO at the same rate regardless of whether useable nitrogen was present. We confirmed that the nitrogen in •NO and its autoxidation products could not be used by E. coli under our experimental conditions, and discovered that •NO eliminated differences in carbon and oxygen consumption between nitrogen-replete and nitrogen-starved cultures. Interestingly, E. coli does not consume measurable extracellular nitrogen during •NO stress despite the need to translate defense enzymes. Further, we found that RelA, which responds to uncharged tRNA, was required to observe the robustness of •NO detoxification to nitrogen starvation. These data demonstrate that E. coli is well poised to detoxify •NO in the absence of useable nitrogen and suggest that the stringent response could be a useful target to potentiate the antibacterial activity of •NO.
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Affiliation(s)
- Xuanqing Wan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA.
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18
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Master regulator NtrC controls the utilization of alternative nitrogen sources in Pseudomonas stutzeri A1501. World J Microbiol Biotechnol 2021; 37:177. [PMID: 34524580 PMCID: PMC8443478 DOI: 10.1007/s11274-021-03144-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/07/2021] [Indexed: 11/25/2022]
Abstract
Pseudomonas stutzeri A1501 is a model strain used to study associative nitrogen fixation, and it possesses the nitrogen regulatory NtrC protein in the core genome. Nitrogen sources represent one of the important factors affecting the efficiency of biological nitrogen fixation in the natural environment. However, the regulation of NtrC during nitrogen metabolism in P. stutzeri A1501 has not been clarified. In this work, a phenotypic analysis of the ntrC mutant characterized the roles of NtrC in nitrogen metabolism and the oxidative stress response of P. stutzeri A1501. To systematically identify NtrC-controlled gene expression, RNA-seq was performed to further analyse the gene expression differences between the wild-type strain and the ∆ntrC mutant under nitrogen fixation conditions. A total of 1431 genes were found to be significantly altered by ntrC deletion, among which 147 associative genes had NtrC-binding sites, and the pathways for nitrogen fixation regulation, nitrogenous compound acquisition and catabolism and nitrate assimilation were discussed. Furthermore, the oxidative stress-related gene (katB), which was upregulated by ntrC deletion, was suggested to be a potential target gene of NtrC, thus highlighting the importance of NtrC in nitrogenase protection against oxygen damage. Based on these findings, we propose that NtrC is a high-ranking element in the regulatory network of P. stutzeri A1501 that controls a variety of nitrogen metabolic and oxidative stress responsive traits required for adaptation to complex rhizosphere environments.
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19
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The Oxoglutarate Binding Site and Regulatory Mechanism Are Conserved in Ammonium Transporter Inhibitors GlnKs from Methanococcales. Int J Mol Sci 2021; 22:ijms22168631. [PMID: 34445335 PMCID: PMC8395244 DOI: 10.3390/ijms22168631] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022] Open
Abstract
Protein inhibition is a natural regulatory process to control cellular metabolic fluxes. PII-family signal-transducing effectors are in this matter key regulators of the nitrogen metabolism. Their interaction with their various targets is governed by the cellular nitrogen level and the energy charge. Structural studies on GlnK, a PII-family inhibitor of the ammonium transporters (Amt), showed that the T-loops responsible for channel obstruction are displaced upon the binding of 2-oxoglutarate, magnesium and ATP in a conserved cleft. However, GlnK from Methanocaldococcus jannaschii was shown to bind 2-oxoglutarate on the tip of its T-loop, causing a moderate disruption to GlnK-Amt interaction, raising the question if methanogenic archaea use a singular adaptive strategy. Here we show that membrane fractions of Methanothermococcus thermolithotrophicus released GlnKs only in the presence of Mg-ATP and 2-oxoglutarate. This observation led us to structurally characterize the two GlnK isoforms apo or in complex with ligands. Together, our results show that the 2-oxoglutarate binding interface is conserved in GlnKs from Methanococcales, including Methanocaldococcus jannaschii, emphasizing the importance of a free carboxy-terminal group to facilitate ligand binding and to provoke the shift of the T-loop positions.
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20
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Haskett TL, Knights HE, Jorrin B, Mendes MD, Poole PS. A Simple in situ Assay to Assess Plant-Associative Bacterial Nitrogenase Activity. Front Microbiol 2021; 12:690439. [PMID: 34248916 PMCID: PMC8261070 DOI: 10.3389/fmicb.2021.690439] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/25/2021] [Indexed: 11/23/2022] Open
Abstract
Assessment of plant-associative bacterial nitrogen (N) fixation is crucial for selection and development of elite diazotrophic inoculants that could be used to supply cereal crops with nitrogen in a sustainable manner. Although diazotrophic bacteria possess diverse oxygen tolerance mechanisms, most require a sub 21% oxygen environment to achieve optimal stability and function of the N-fixing catalyst nitrogenase. Consequently, assessment of N fixation is routinely carried out on “free-living” bacteria grown in the absence of a host plant and such experiments may not accurately divulge activity in the rhizosphere where the availability and forms of nutrients such as carbon and N, which are key regulators of N fixation, may vary widely. Here, we present a modified in situ acetylene reduction assay (ARA), utilizing the model cereal barley as a host to comparatively assess nitrogenase activity in diazotrophic bacteria. The assay is rapid, highly reproducible, applicable to a broad range of diazotrophs, and can be performed with simple equipment commonly found in most laboratories that investigate plant-microbe interactions. Thus, the assay could serve as a first point of order for high-throughput identification of elite plant-associative diazotrophs.
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Affiliation(s)
- Timothy L Haskett
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Hayley E Knights
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Beatriz Jorrin
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Marta D Mendes
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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21
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Chen H, Wang Q. Regulatory mechanisms of lipid biosynthesis in microalgae. Biol Rev Camb Philos Soc 2021; 96:2373-2391. [PMID: 34101323 DOI: 10.1111/brv.12759] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
Microalgal lipids are highly promising feedstocks for biofuel production. Microalgal lipids, especially triacylglycerol, and practical applications of these compounds have received increasing attention in recent years. For the commercial use of microalgal lipids to be feasible, many fundamental biological questions must be addressed based on detailed studies of algal biology, including how lipid biosynthesis occurs and is regulated. Here, we review the current understanding of microalgal lipid biosynthesis, with a focus on the underlying regulatory mechanisms. We also present possible solutions for overcoming various obstacles to understanding the basic biology of microalgal lipid biosynthesis and the practical application of microalgae-based lipids. This review will provide a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly pertaining to microalgal-based lipid biosynthesis.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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22
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Zhai Z, Keereetaweep J, Liu H, Xu C, Shanklin J. The Role of Sugar Signaling in Regulating Plant Fatty Acid Synthesis. FRONTIERS IN PLANT SCIENCE 2021; 12:643843. [PMID: 33828577 PMCID: PMC8020596 DOI: 10.3389/fpls.2021.643843] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/17/2021] [Indexed: 05/07/2023]
Abstract
Photosynthates such as glucose, sucrose, and some of their derivatives play dual roles as metabolic intermediates and signaling molecules that influence plant cell metabolism. Such sugars provide substrates for de novo fatty acid (FA) biosynthesis. However, compared with the well-defined examples of sugar signaling in starch and anthocyanin synthesis, until recently relatively little was known about the role of signaling in regulating FA and lipid biosynthesis. Recent research progress shows that trehalose 6-phosphate and 2-oxoglutarate (2-OG) play direct signaling roles in the regulation of FA biosynthesis by modulating transcription factor stability and enzymatic activities involved in FA biosynthesis. Specifically, mechanistic links between sucrose non-fermenting-1-related protein kinase 1 (SnRK1)-mediated trehalose 6-phosphate (T6P) sensing and its regulation by phosphorylation of WRI1 stability, diacylglycerol acyltransferase 1 (DGAT1) enzyme activity, and of 2-OG-mediated relief of inhibition of acetyl-CoA carboxylase (ACCase) activity by protein PII are exemplified in detail in this review.
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23
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Brewitz L, Nakashima Y, Schofield CJ. Synthesis of 2-oxoglutarate derivatives and their evaluation as cosubstrates and inhibitors of human aspartate/asparagine-β-hydroxylase. Chem Sci 2020; 12:1327-1342. [PMID: 34163896 PMCID: PMC8179049 DOI: 10.1039/d0sc04301j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/26/2020] [Indexed: 02/06/2023] Open
Abstract
2-Oxoglutarate (2OG) is involved in biological processes including oxidations catalyzed by 2OG oxygenases for which it is a cosubstrate. Eukaryotic 2OG oxygenases have roles in collagen biosynthesis, lipid metabolism, DNA/RNA modification, transcriptional regulation, and the hypoxic response. Aspartate/asparagine-β-hydroxylase (AspH) is a human 2OG oxygenase catalyzing post-translational hydroxylation of Asp/Asn-residues in epidermal growth factor-like domains (EGFDs) in the endoplasmic reticulum. AspH is of chemical interest, because its Fe(ii) cofactor is complexed by two rather than the typical three residues. AspH is upregulated in hypoxia and is a prognostic marker on the surface of cancer cells. We describe studies on how derivatives of its natural 2OG cosubstrate modulate AspH activity. An efficient synthesis of C3- and/or C4-substituted 2OG derivatives, proceeding via cyanosulfur ylid intermediates, is reported. Mass spectrometry-based AspH assays with >30 2OG derivatives reveal that some efficiently inhibit AspH via competing with 2OG as evidenced by crystallographic and solution analyses. Other 2OG derivatives can substitute for 2OG enabling substrate hydroxylation. The results show that subtle changes, e.g. methyl- to ethyl-substitution, can significantly alter the balance between catalysis and inhibition. 3-Methyl-2OG, a natural product present in human nutrition, was the most efficient alternative cosubstrate identified; crystallographic analyses reveal the binding mode of (R)-3-methyl-2OG and other 2OG derivatives to AspH and inform on the balance between turnover and inhibition. The results will enable the use of 2OG derivatives as mechanistic probes for other 2OG utilizing enzymes and suggest 2-oxoacids other than 2OG may be employed by some 2OG oxygenases in vivo.
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Affiliation(s)
- Lennart Brewitz
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road OX1 3TA Oxford UK
| | - Yu Nakashima
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road OX1 3TA Oxford UK
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24
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Unden G, Klein R. Sensing of O 2 and nitrate by bacteria: alternative strategies for transcriptional regulation of nitrate respiration by O 2 and nitrate. Environ Microbiol 2020; 23:5-14. [PMID: 33089915 DOI: 10.1111/1462-2920.15293] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/28/2022]
Abstract
Many bacteria are able to use O2 and nitrate as alternative electron acceptors for respiration. Strategies for regulation in response to O2 and nitrate can vary considerably. In the paradigmatic system of E. coli (and γ-proteobacteria), regulation by O2 and nitrate is established by the O2 -sensor FNR and the two-component system NarX-NarL (for nitrate regulation). Expression of narGHJI is regulated by the binding of FNR and NarL to the promoter. A similar strategy by individual regulation in response to O2 and nitrate is verified in many genera by the use of various types of regulators. Otherwise, in the soil bacteria Bacillus subtilis (Firmicutes) and Streptomyces (Actinobacteria), nitrate respiration is subject to anaerobic induction, without direct nitrate induction. In contrast, the NreA-NreB-NreC two-component system of Staphylococcus (Firmicutes) performs joint sensing of O2 and nitrate by interacting O2 and nitrate sensors. The O2 -sensor NreB phosphorylates the response regulator NreC to activate narGHJI expression. NreC-P transmits the signal for anaerobiosis to the promoter. The nitrate sensor NreA modulates NreB function by converting NreB in the absence of nitrate from the kinase to a phosphatase that dephosphorylates NreC-P. Thus, widely different strategies for coordinating the response to O2 and nitrate have evolved in bacteria.
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Affiliation(s)
- Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, 55099, Germany
| | - Robin Klein
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, 55099, Germany
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25
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Forchhammer K, Selim KA. Carbon/nitrogen homeostasis control in cyanobacteria. FEMS Microbiol Rev 2020; 44:33-53. [PMID: 31617886 PMCID: PMC8042125 DOI: 10.1093/femsre/fuz025] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/14/2019] [Indexed: 02/06/2023] Open
Abstract
Carbon/nitrogen (C/N) balance sensing is a key requirement for the maintenance of cellular homeostasis. Therefore, cyanobacteria have evolved a sophisticated signal transduction network targeting the metabolite 2-oxoglutarate (2-OG), the carbon skeleton for nitrogen assimilation. It serves as a status reporter for the cellular C/N balance that is sensed by transcription factors NtcA and NdhR and the versatile PII-signaling protein. The PII protein acts as a multitasking signal-integrating regulator, combining the 2-OG signal with the energy state of the cell through adenyl-nucleotide binding. Depending on these integrated signals, PII orchestrates metabolic activities in response to environmental changes through binding to various targets. In addition to 2-OG, other status reporter metabolites have recently been discovered, mainly indicating the carbon status of the cells. One of them is cAMP, which is sensed by the PII-like protein SbtB. The present review focuses, with a main emphasis on unicellular model strains Synechoccus elongatus and Synechocystis sp. PCC 6803, on the physiological framework of these complex regulatory loops, the tight linkage to metabolism and the molecular mechanisms governing the signaling processes.
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Affiliation(s)
- Karl Forchhammer
- Lehrstuhl für Mikrobiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| | - Khaled A Selim
- Lehrstuhl für Mikrobiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
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Adhikary R, Kundu S, Maiti PK, Mitra PK, Mandal S, Mandal V. Effect of different stimuli on twitching behavior of endophytic bacteria isolated from Loranthus sp. Jacq. Antonie van Leeuwenhoek 2020; 113:1489-1505. [PMID: 32789713 DOI: 10.1007/s10482-020-01458-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 08/03/2020] [Indexed: 11/29/2022]
Abstract
Bacteria need to adopt to different behavioral tuning depending on the dynamic eco-physiological conditions they are exposed to. One of these adaptive strategies is the use of motility. Here we report the twitching motility response of four endophytic isolates of Bacillus sp. when exposed to different eco-physiological stimuli like different nutrient sources, and mechanical and chemical antagonists on solid surfaces. These endophytic bacteria were isolated from different parts of a hemiparasite Loranthus sp. Jacq. (Loranthaceae) growing on economically important mango trees. The results show that the twitching motility of these bacteria was more when exposed to organic acids, metals salts (among nutrients) and mechanical shearing (stress) than the other factors. Their motility is not affected by surface lubrication or EPS production, but instead is influenced by shear-sensitive structures and affinity to metal ions. Further molecular studies are needed to elucidate the basis of this twitching behaviour on solid surfaces.
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Affiliation(s)
| | - Smriti Kundu
- University of Gour Banga, Malda, West Bengal, India
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Covert Cross-Feeding Revealed by Genome-Wide Analysis of Fitness Determinants in a Synthetic Bacterial Mutualism. Appl Environ Microbiol 2020; 86:AEM.00543-20. [PMID: 32332139 DOI: 10.1128/aem.00543-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/17/2020] [Indexed: 01/02/2023] Open
Abstract
Microbial interactions abound in natural ecosystems and shape community structure and function. Substantial attention has been given to cataloging mechanisms by which microbes interact, but there is a limited understanding of the genetic landscapes that promote or hinder microbial interactions. We previously developed a mutualistic coculture pairing Escherichia coli and Rhodopseudomonas palustris, wherein E. coli provides carbon to R. palustris in the form of glucose fermentation products and R. palustris fixes N2 gas and provides nitrogen to E. coli in the form of NH4 + The stable coexistence and reproducible trends exhibited by this coculture make it ideal for interrogating the genetic underpinnings of a cross-feeding mutualism. Here, we used random barcode transposon sequencing (RB-TnSeq) to conduct a genome-wide search for E. coli genes that influence fitness during cooperative growth with R. palustris RB-TnSeq revealed hundreds of genes that increased or decreased E. coli fitness in a mutualism-dependent manner. Some identified genes were involved in nitrogen sensing and assimilation, as expected given the coculture design. The other identified genes were involved in diverse cellular processes, including energy production and cell wall and membrane biogenesis. In addition, we discovered unexpected purine cross-feeding from R. palustris to E. coli, with coculture rescuing growth of an E. coli purine auxotroph. Our data provide insight into the genes and gene networks that can influence a cross-feeding mutualism and underscore that microbial interactions are not necessarily predictable a priori IMPORTANCE Microbial communities impact life on Earth in profound ways, including driving global nutrient cycles and influencing human health and disease. These community functions depend on the interactions that resident microbes have with the environment and each other. Thus, identifying genes that influence these interactions will aid the management of natural communities and the use of microbial consortia as biotechnology. Here, we identified genes that influenced Escherichia coli fitness during cooperative growth with a mutualistic partner, Rhodopseudomonas palustris Although this mutualism centers on the bidirectional exchange of essential carbon and nitrogen, E. coli fitness was positively and negatively affected by genes involved in diverse cellular processes. Furthermore, we discovered an unexpected purine cross-feeding interaction. These results contribute knowledge on the genetic foundation of a microbial cross-feeding interaction and highlight that unanticipated interactions can occur even within engineered microbial communities.
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Dynamic resource allocation drives growth under nitrogen starvation in eukaryotes. NPJ Syst Biol Appl 2020; 6:14. [PMID: 32415097 PMCID: PMC7229059 DOI: 10.1038/s41540-020-0135-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/16/2020] [Indexed: 12/18/2022] Open
Abstract
Cells can sense changes in their extracellular environment and subsequently adapt their biomass composition. Nutrient abundance defines the capability of the cell to produce biomass components. Under nutrient-limited conditions, resource allocation dramatically shifts to carbon-rich molecules. Here, we used dynamic biomass composition data to predict changes in growth and reaction flux distributions using the available genome-scale metabolic models of five eukaryotic organisms (three heterotrophs and two phototrophs). We identified temporal profiles of metabolic fluxes that indicate long-term trends in pathway and organelle function in response to nitrogen depletion. Surprisingly, our calculations of model sensitivity and biosynthetic cost showed that free energy of biomass metabolites is the main driver of biosynthetic cost and not molecular weight, thus explaining the high costs of arginine and histidine. We demonstrated how metabolic models can accurately predict the complexity of interwoven mechanisms in response to stress over the course of growth.
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Klein R, Kretzschmar A, Unden G. Control of the bifunctional O
2
‐sensor kinase NreB of
Staphylococcus carnosus
by the nitrate sensor NreA: Switching from kinase to phosphatase state. Mol Microbiol 2019; 113:369-380. [DOI: 10.1111/mmi.14425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Robin Klein
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
| | - Ann‐Katrin Kretzschmar
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
| | - Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
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Abstract
Rhizobia are α- and β-proteobacteria that form a symbiotic partnership with legumes, fixing atmospheric dinitrogen to ammonia and providing it to the plant. Oxygen regulation is key in this symbiosis. Fixation is performed by an oxygen-intolerant nitrogenase enzyme but requires respiration to meet its high energy demands. To satisfy these opposing constraints the symbiotic partners cooperate intimately, employing a variety of mechanisms to regulate and respond to oxygen concentration. During symbiosis rhizobia undergo significant changes in gene expression to differentiate into nitrogen-fixing bacteroids. Legumes host these bacteroids in specialized root organs called nodules. These generate a near-anoxic environment using an oxygen diffusion barrier, oxygen-binding leghemoglobin and control of mitochondria localization. Rhizobia sense oxygen using multiple interconnected systems which enable a finely-tuned response to the wide range of oxygen concentrations they experience when transitioning from soil to nodules. The oxygen-sensing FixL-FixJ and hybrid FixL-FxkR two-component systems activate at relatively high oxygen concentration and regulate fixK transcription. FixK activates the fixNOQP and fixGHIS operons producing a high-affinity terminal oxidase required for bacterial respiration in the microaerobic nodule. Additionally or alternatively, some rhizobia regulate expression of these operons by FnrN, an FNR-like oxygen-sensing protein. The final stage of symbiotic establishment is activated by the NifA protein, regulated by oxygen at both the transcriptional and protein level. A cross-species comparison of these systems highlights differences in their roles and interconnections but reveals common regulatory patterns and themes. Future work is needed to establish the complete regulon of these systems and identify other regulatory signals.
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Affiliation(s)
- Paul J Rutten
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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31
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Xu M, Li J, Shu Q, Tang M, Zhang X, Yang T, Xu Z, Rao Z. Enhancement of L-arginine production by increasing ammonium uptake in an AmtR-deficient Corynebacterium crenatum mutant. J Ind Microbiol Biotechnol 2019; 46:1155-1166. [PMID: 31203489 DOI: 10.1007/s10295-019-02204-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 06/07/2019] [Indexed: 12/13/2022]
Abstract
L-Arginine is an important amino acid with extensive application in the food and pharmaceutical industries. The efficiency of nitrogen uptake and assimilation by organisms is extremely important for L-arginine production. In this study, a strain engineering strategy focusing on upregulate intracellular nitrogen metabolism in Corynebacterium crenatum for L-arginine production was conducted. Firstly, the nitrogen metabolism global transcriptional regulator AmtR was deleted, which has demonstrated the beneficial effect on L-arginine production. Subsequently, this strain was engineered by overexpressing the ammonium transporter AmtB to increase the uptake of NH4+ and L-arginine production. To overcome the drawbacks of using a plasmid to express amtB, Ptac, a strong promoter with amtB gene fragment, was integrated into the amtR region on the chromosome in the Corynebacterium crenatum/ΔamtR. The final strain results in L-arginine production at a titer of 60.9 g/L, which was 35.14% higher than that produced by C. crenatum SYPA5-5.
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Affiliation(s)
- Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China. .,Jiangnan University (Rugao) Food Biotechnology Research Institute, Rugao, 226500, Jiangsu, China.
| | - Jing Li
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Qunfeng Shu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Mi Tang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Zhenghong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
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Manipulating nitrogen regulation in diazotrophic bacteria for agronomic benefit. Biochem Soc Trans 2019; 47:603-614. [PMID: 30936245 PMCID: PMC6490700 DOI: 10.1042/bst20180342] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 11/29/2022]
Abstract
Biological nitrogen fixation (BNF) is controlled by intricate regulatory mechanisms to ensure that fixed nitrogen is readily assimilated into biomass and not released to the environment. Understanding the complex regulatory circuits that couple nitrogen fixation to ammonium assimilation is a prerequisite for engineering diazotrophic strains that can potentially supply fixed nitrogen to non-legume crops. In this review, we explore how the current knowledge of nitrogen metabolism and BNF regulation may allow strategies for genetic manipulation of diazotrophs for ammonia excretion and provide a contribution towards solving the nitrogen crisis.
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Tejada-Jimenez M, Llamas A, Galván A, Fernández E. Role of Nitrate Reductase in NO Production in Photosynthetic Eukaryotes. PLANTS 2019; 8:plants8030056. [PMID: 30845759 PMCID: PMC6473468 DOI: 10.3390/plants8030056] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 12/20/2022]
Abstract
Nitric oxide is a gaseous secondary messenger that is critical for proper cell signaling and plant survival when exposed to stress. Nitric oxide (NO) synthesis in plants, under standard phototrophic oxygenic conditions, has long been a very controversial issue. A few algal strains contain NO synthase (NOS), which appears to be absent in all other algae and land plants. The experimental data have led to the hypothesis that molybdoenzyme nitrate reductase (NR) is the main enzyme responsible for NO production in most plants. Recently, NR was found to be a necessary partner in a dual system that also includes another molybdoenzyme, which was renamed NO-forming nitrite reductase (NOFNiR). This enzyme produces NO independently of the molybdenum center of NR and depends on the NR electron transport chain from NAD(P)H to heme. Under the circumstances in which NR is not present or active, the existence of another NO-forming system that is similar to the NOS system would account for NO production and NO effects. PII protein, which senses and integrates the signals of the C–N balance in the cell, likely has an important role in organizing cell responses. Here, we critically analyze these topics.
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Affiliation(s)
- Manuel Tejada-Jimenez
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Angel Llamas
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Aurora Galván
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, 14071 Córdoba, Spain.
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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35
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The deuridylylation activity of Herbaspirillum seropedicae GlnD protein is regulated by the glutamine:2-oxoglutarate ratio. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:1216-1223. [DOI: 10.1016/j.bbapap.2018.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/22/2018] [Accepted: 09/25/2018] [Indexed: 11/21/2022]
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36
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Zalutskaya Z, Kochemasova L, Ermilova E. Dual positive and negative control of Chlamydomonas PII signal transduction protein expression by nitrate/nitrite and NO via the components of nitric oxide cycle. BMC PLANT BIOLOGY 2018; 18:305. [PMID: 30482162 PMCID: PMC6258461 DOI: 10.1186/s12870-018-1540-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/20/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND The PII proteins constitute a large superfamily, present in all domains of life. Until now, PII proteins research in Chloroplastida (green algae and land plants) has mainly focused on post-translation regulation of these signal transductors. Emerging evidence suggests that PII level is tightly controlled with regard to the nitrogen source and the physiological state of cells. RESULT Here we identify that a balance of positive (nitrate and nitrite) and negative (nitric oxide) signals regulates Chlamydomonas GLB1. We found that PII expression is downregulated by ammonium through a nitric oxide (NO)-dependent mechanism. We show that nitrate reductase (NR) and its partner, truncated hemoglobin 1 (THB1), participate in a signaling pathway for dual control of GLB1 expression. Moreover, NO dependent guanilate cyclase appeared to be involved in the negative control of GLB1 transcription. CONCLUSION This study has revealed the existence of the complex GLB1 control at transcription level, which is dependent on nitrogen source. Importantly, we found that GLB1 gene expression pattern is very similar to that observed for nitrate assimilation genes, suggesting interconnecting/coordinating PII-dependent and nitrate assimilation pathways.
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Affiliation(s)
- Zhanneta Zalutskaya
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Lidiya Kochemasova
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Elena Ermilova
- Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
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Mara P, Fragiadakis GS, Gkountromichos F, Alexandraki D. The pleiotropic effects of the glutamate dehydrogenase (GDH) pathway in Saccharomyces cerevisiae. Microb Cell Fact 2018; 17:170. [PMID: 30384856 PMCID: PMC6211499 DOI: 10.1186/s12934-018-1018-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/29/2018] [Indexed: 12/19/2022] Open
Abstract
Ammonium assimilation is linked to fundamental cellular processes that include the synthesis of non-essential amino acids like glutamate and glutamine. In Saccharomyces cerevisiae glutamate can be synthesized from α-ketoglutarate and ammonium through the action of NADP-dependent glutamate dehydrogenases Gdh1 and Gdh3. Gdh1 and Gdh3 are evolutionarily adapted isoforms and cover the anabolic role of the GDH-pathway. Here, we review the role and function of the GDH pathway in glutamate metabolism and we discuss the additional contributions of the pathway in chromatin regulation, nitrogen catabolite repression, ROS-mediated apoptosis, iron deficiency and sphingolipid-dependent actin cytoskeleton modulation in S.cerevisiae. The pleiotropic effects of GDH pathway in yeast biology highlight the importance of glutamate homeostasis in vital cellular processes and reveal new features for conserved enzymes that were primarily characterized for their metabolic capacity. These newly described features constitute insights that can be utilized for challenges regarding genetic engineering of glutamate homeostasis and maintenance of redox balances, biosynthesis of important metabolites and production of organic substrates. We also conclude that the discussed pleiotropic features intersect with basic metabolism and set a new background for further glutamate-dependent applied research of biotechnological interest.
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Affiliation(s)
- P. Mara
- Department of Chemistry, University of Crete, Voutes University Campus, 71003 Heraklion, Crete Greece
- Present Address: Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA
| | - G. S. Fragiadakis
- Institute of Molecular Biology & Biotechnology, FORTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete Greece
| | - F. Gkountromichos
- Department of Biology, University of Crete, Voutes University Campus, 71003 Heraklion, Crete Greece
- Faculty of Biology, Biocenter, Ludwig-Maximilians-University of Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - D. Alexandraki
- Department of Biology, University of Crete, Voutes University Campus, 71003 Heraklion, Crete Greece
- Institute of Molecular Biology & Biotechnology, FORTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete Greece
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The Nitrogen Regulatory PII Protein (GlnB) and N-Acetylglucosamine 6-Phosphate Epimerase (NanE) Allosterically Activate Glucosamine 6-Phosphate Deaminase (NagB) in Escherichia coli. J Bacteriol 2018; 200:JB.00691-17. [PMID: 29229699 DOI: 10.1128/jb.00691-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022] Open
Abstract
Amino sugars are good sources of both ammonia and fructose-6-phosphate, produced by the glucosamine 6-phosphate deaminase, NagB. NagB is known to be allosterically regulated by N-acetylglucosamine 6-phosphate (GlcNAc-6P) and the phosphocarrier protein of the bacterial phosphotransferase system, HPr, in Escherichia coli We provide evidence that NanE, GlcNAc-6P epimerase, and the uridylylated PII protein (U-PII) also allosterically activate NagB by direct protein-protein interactions. NanE is essential for neuraminic acid (NANA) and N-acetylmannosamine (ManNAc) utilization, and PII is known to be a central metabolic nitrogen regulator. We demonstrate that uridylylated PII (but not underivatized PII) activates NagB >10-fold at low concentrations of substrate, whereas NanE increases NagB activity >2-fold. NanE activates NagB in the absence or presence of GlcNAc-6P, but HPr and U-PII activation requires the presence of GlcNAc-6P. Activation of NagB by HPr and uridylylated PII, as well as by NanE and HPr (but not by NanE and U-PII), is synergistic, and the modeling, which suggests specific residues involved in complex formation, provides possible explanations. Specific physiological functions for the regulation of NagB by its three protein activators are proposed. Each regulatory agent is suggested to mediate signal transduction in response to a different stimulus.IMPORTANCE The regulation of amino sugar utilization is important for the survival of bacteria in a competitive environment. NagB, a glucosamine 6-phosphate deaminase in Escherichia coli, is essential for amino sugar utilization and is known to be allosterically regulated by N-acetylglucosamine 6-phosphate (GlcNAc-6P) and the histidine-phosphorylatable phosphocarrier protein, HPr. We provide evidence here that NanE, GlcNAc-6P epimerase, and the uridylylated PII protein allosterically activate NagB by direct protein-protein interactions. NanE is essential for N-acetylneuraminic acid (NANA) and N-acetylmannosamine (ManNAc) utilization, and the PII protein is known to be a central metabolic nitrogen regulator. Regulatory links between carbon and nitrogen metabolism are important for adaptation of metabolism to different growth conditions.
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Mairet F. A biomolecular proportional integral controller based on feedback regulations of protein level and activity. ROYAL SOCIETY OPEN SCIENCE 2018. [PMID: 29515895 PMCID: PMC5830784 DOI: 10.1098/rsos.171966] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Homeostasis is the capacity of living organisms to keep internal conditions regulated at a constant level, despite environmental fluctuations. Integral feedback control is known to play a key role in this behaviour. Here, I show that a feedback system involving transcriptional and post-translational regulations of the same executor protein acts as a proportional integral (PI) controller, leading to enhanced transient performances in comparison with a classical integral loop. Such a biomolecular controller-which I call a level and activity-PI controller (LA-PI)-is involved in the regulation of ammonium uptake by Escherichia coli through the transporter AmtB. The P II molecules, which reflect the nitrogen status of the cell, inhibit both the production of AmtB and its activity (via the NtrB-NtrC system and the formation of a complex with GlnK, respectively). Other examples of LA-PI controller include copper and zinc transporters, and the redox regulation in photosynthesis. This scheme has thus emerged through evolution in many biological systems, surely because of the benefits it offers in terms of performances (rapid and perfect adaptation) and economy (protein production according to needs).
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Affiliation(s)
- Francis Mairet
- Biocore, Inria, Sophia Antipolis, France
- Physiology and Biotechnology of Algae Laboratory, Ifremer, Nantes, France
- Author for correspondence: Francis Mairet e-mail:
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Krupovic M, Koonin EV. Cellular origin of the viral capsid-like bacterial microcompartments. Biol Direct 2017; 12:25. [PMID: 29132422 PMCID: PMC5683377 DOI: 10.1186/s13062-017-0197-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/06/2017] [Indexed: 11/10/2022] Open
Abstract
ᅟ: Bacterial microcompartments (BMC) are proteinaceous organelles that structurally resemble viral capsids, but encapsulate enzymes that perform various specialized biochemical reactions in the cell cytoplasm. The BMC are constructed from two major shell proteins, BMC-H and BMC-P, which form the facets and vertices of the icosahedral assembly, and are functionally equivalent to the major and minor capsid proteins of viruses, respectively. This equivalence notwithstanding, neither of the BMC proteins displays structural similarity to known capsid proteins, rendering the origins of the BMC enigmatic. Here, using structural and sequence comparisons, we show that both BMC-H and BMC-P, most likely, were exapted from bona fide cellular proteins, namely, PII signaling protein and OB-fold domain-containing protein, respectively. This finding is in line with the hypothesis that many major viral structural proteins have been recruited from cellular proteomes. REVIEWERS This article was reviewed by Igor Zhulin, Jeremy Selengut and Narayanaswamy Srinivasan. For complete reviews, see the Reviewers' reports section.
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Affiliation(s)
- Mart Krupovic
- Department of Microbiology, Institut Pasteur, 25 rue du Dr. Roux, 75015, Paris, France.
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
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Sequencing and Characterization of Novel PII Signaling Protein Gene in Microalga Haematococcus pluvialis. Mar Drugs 2017; 15:md15100304. [PMID: 29019908 PMCID: PMC5666412 DOI: 10.3390/md15100304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/25/2017] [Accepted: 09/30/2017] [Indexed: 11/17/2022] Open
Abstract
The PII signaling protein is a key protein for controlling nitrogen assimilatory reactions in most organisms, but little information is reported on PII proteins of green microalga Haematococcus pluvialis. Since H. pluvialis cells can produce a large amount of astaxanthin upon nitrogen starvation, its PII protein may represent an important factor on elevated production of Haematococcus astaxanthin. This study identified and isolated the coding gene (HpGLB1) from this microalga. The full-length of HpGLB1 was 1222 bp, including 621 bp coding sequence (CDS), 103 bp 5' untranslated region (5' UTR), and 498 bp 3' untranslated region (3' UTR). The CDS could encode a protein with 206 amino acids (HpPII). Its calculated molecular weight (Mw) was 22.4 kDa and the theoretical isoelectric point was 9.53. When H. pluvialis cells were exposed to nitrogen starvation, the HpGLB1 expression was increased 2.46 times in 48 h, concomitant with the raise of astaxanthin content. This study also used phylogenetic analysis to prove that HpPII was homogeneous to the PII proteins of other green microalgae. The results formed a fundamental basis for the future study on HpPII, for its potential physiological function in Haematococcus astaxanthin biosysthesis.
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Gerhardt ECM, Moure VR, Souza AW, Pedrosa FO, Souza EM, Diacovich L, Gramajo H, Huergo LF. Expression and purification of untagged GlnK proteins from actinobacteria. EXCLI JOURNAL 2017; 16:949-958. [PMID: 28900375 PMCID: PMC5579400 DOI: 10.17179/excli2017-394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/12/2017] [Indexed: 11/16/2022]
Abstract
The PII protein family constitutes one of the most conserved and well distributed family of signal transduction proteins in nature. These proteins play key roles in nitrogen and carbon metabolism. PII function has been well documented in Gram-negative bacteria. However, there are very few reports describing the in vitro properties and function of PII derived from Gram-positive bacteria. Here we present the heterologous expression and efficient purification protocols for untagged PII from three Actinobacteria of medical and biotechnological interest namely: Mycobacterium tuberculosis, Rhodococcus jostii and Streptomyces coelicolor. Circular dichroism and gel filtration analysis supported that the purified proteins are correctly folded. The purification protocol described here will facilitate biochemical studies and help to uncover the biochemical functions of PII proteins in Actinobacteria.
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Affiliation(s)
| | - Vivian R Moure
- Departamento de Bioquímica e Biologia Molecular, UFPR, Curitiba, Brazil
| | - Andrey W Souza
- Departamento de Bioquímica e Biologia Molecular, UFPR, Curitiba, Brazil
| | - Fabio O Pedrosa
- Departamento de Bioquímica e Biologia Molecular, UFPR, Curitiba, Brazil
| | - Emanuel M Souza
- Departamento de Bioquímica e Biologia Molecular, UFPR, Curitiba, Brazil
| | - Lautaro Diacovich
- Instituto de Biologia Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo Gramajo
- Instituto de Biologia Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Luciano F Huergo
- Departamento de Bioquímica e Biologia Molecular, UFPR, Curitiba, Brazil.,Setor Litoral, UFPR, Matinhos, Brazil
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Whiteley AT, Garelis NE, Peterson BN, Choi PH, Tong L, Woodward JJ, Portnoy DA. c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation. Mol Microbiol 2017; 104:212-233. [PMID: 28097715 DOI: 10.1111/mmi.13622] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2017] [Indexed: 12/26/2022]
Abstract
Cyclic diadenosine monophosphate (c-di-AMP) is a conserved nucleotide second messenger critical for bacterial growth and resistance to cell wall-active antibiotics. In Listeria monocytogenes, the sole diadenylate cyclase, DacA, is essential in rich, but not synthetic media and ΔdacA mutants are highly sensitive to the β-lactam antibiotic cefuroxime. In this study, loss of function mutations in the oligopeptide importer (oppABCDF) and glycine betaine importer (gbuABC) allowed ΔdacA mutants to grow in rich medium. Since oligopeptides were sufficient to inhibit growth of the ΔdacA mutant we hypothesized that oligopeptides act as osmolytes, similar to glycine betaine, to disrupt intracellular osmotic pressure. Supplementation with salt stabilized the ΔdacA mutant in rich medium and restored cefuroxime resistance. Additional suppressor mutations in the acetyl-CoA binding site of pyruvate carboxylase (PycA) rescued cefuroxime resistance and resulted in a 100-fold increase in virulence of the ΔdacA mutant. PycA is inhibited by c-di-AMP and these mutations prompted us to examine the role of TCA cycle enzymes. Inactivation of citrate synthase, but not down-stream enzymes suppressed ΔdacA phenotypes. These data suggested that c-di-AMP modulates central metabolism at the pyruvate node to moderate citrate production and indeed, the ΔdacA mutant accumulated six times the concentration of citrate present in wild-type bacteria.
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Affiliation(s)
- Aaron T Whiteley
- Graduate Group in Infectious Diseases and Immunity, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Nicholas E Garelis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Bret N Peterson
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, CA, USA
| | - Philip H Choi
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,School of Public Health, University of California, Berkeley, Berkeley, CA, USA
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VfrB Is a Key Activator of the Staphylococcus aureus SaeRS Two-Component System. J Bacteriol 2017; 199:JB.00828-16. [PMID: 28031278 DOI: 10.1128/jb.00828-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 12/22/2022] Open
Abstract
In previous studies, we identified the fatty acid kinase virulence factor regulator B (VfrB) as a potent regulator of α-hemolysin and other virulence factors in Staphylococcus aureus In this study, we demonstrated that VfrB is a positive activator of the SaeRS two-component regulatory system. Analysis of vfrB, saeR, and saeS mutant strains revealed that VfrB functions in the same pathway as SaeRS. At the transcriptional level, the promoter activities of SaeRS class I (coa) and class II (hla) target genes were downregulated during the exponential growth phase in the vfrB mutant, compared to the wild-type strain. In addition, saePQRS expression was decreased in the vfrB mutant strain, demonstrating a need for this protein in the autoregulation of SaeRS. The requirement for VfrB-mediated activation was circumvented when SaeS was constitutively active due to an SaeS (L18P) substitution. Furthermore, activation of SaeS via human neutrophil peptide 1 (HNP-1) overcame the dependence on VfrB for transcription from class I Sae promoters. Consistent with the role of VfrB in fatty acid metabolism, hla expression was decreased in the vfrB mutant with the addition of exogenous myristic acid. Lastly, we determined that aspartic acid residues D38 and D40, which are predicted to be key to VfrB enzymatic activity, were required for VfrB-mediated α-hemolysin production. Collectively, this study implicates VfrB as a novel accessory protein needed for the activation of SaeRS in S. aureusIMPORTANCE The SaeRS two-component system is a key regulator of virulence determinant production in Staphylococcus aureus Although the regulon of this two-component system is well characterized, the activation mechanisms, including the specific signaling molecules, remain elusive. Elucidating the complex regulatory circuit of SaeRS regulation is important for understanding how the system contributes to disease causation by this pathogen. To this end, we have identified the fatty acid kinase VfrB as a positive regulatory modulator of SaeRS-mediated transcription of virulence factors in S. aureus In addition to describing a new regulatory aspect of SaeRS, this study establishes a link between fatty acid kinase activity and virulence factor regulation.
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Engineering glucose metabolism of Escherichia coli under nitrogen starvation. NPJ Syst Biol Appl 2017; 3:16035. [PMID: 28725483 PMCID: PMC5516864 DOI: 10.1038/npjsba.2016.35] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/07/2016] [Accepted: 10/05/2016] [Indexed: 12/02/2022] Open
Abstract
A major aspect of microbial metabolic engineering is the development of chassis hosts that have favorable global metabolic phenotypes, and can be further engineered to produce a variety of compounds. In this work, we focus on the problem of decoupling growth and production in the model bacterium Escherichia coli, and in particular on the maintenance of active metabolism during nitrogen-limited stationary phase. We find that by overexpressing the enzyme PtsI, a component of the glucose uptake system that is inhibited by α-ketoglutarate during nitrogen limitation, we are able to achieve a fourfold increase in metabolic rates. Alternative systems were also tested: chimeric PtsI proteins hypothesized to be insensitive to α-ketoglutarate did not improve metabolic rates under the conditions tested, whereas systems based on the galactose permease GalP suffered from energy stress and extreme sensitivity to expression level. Overexpression of PtsI is likely to be a useful arrow in the metabolic engineer’s quiver as productivity of engineered pathways becomes limited by central metabolic rates during stationary phase production processes.
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Martín-Mora D, Ortega A, Reyes-Darias JA, García V, López-Farfán D, Matilla MA, Krell T. Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate. Front Microbiol 2016; 7:1937. [PMID: 27965656 PMCID: PMC5126104 DOI: 10.3389/fmicb.2016.01937] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/17/2016] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an ubiquitous pathogen able to infect humans, animals, and plants. Chemotaxis was found to be associated with the virulence of this and other pathogens. Although established as a model for chemotaxis research, the majority of the 26 P. aeruginosa chemoreceptors remain functionally un-annotated. We report here the identification of PA5072 (named McpK) as chemoreceptor for α-ketoglutarate (αKG). High-throughput thermal shift assays and isothermal titration calorimetry studies (ITC) of the recombinant McpK ligand binding domain (LBD) showed that it recognizes exclusively α-ketoglutarate. The ITC analysis indicated that the ligand bound with positive cooperativity (Kd1 = 301 μM, Kd2 = 81 μM). McpK is predicted to possess a helical bimodular (HBM) type of LBD and this and other studies suggest that this domain type may be associated with the recognition of organic acids. Analytical ultracentrifugation (AUC) studies revealed that McpK-LBD is present in monomer-dimer equilibrium. Alpha-KG binding stabilized the dimer and dimer self-dissociation constants of 55 μM and 5.9 μM were derived for ligand-free and αKG-bound forms of McpK-LBD, respectively. Ligand-induced LBD dimer stabilization has been observed for other HBM domain containing receptors and may correspond to a general mechanism of this protein family. Quantitative capillary chemotaxis assays demonstrated that P. aeruginosa showed chemotaxis to a broad range of αKG concentrations with maximal responses at 500 μM. Deletion of the mcpK gene reduced chemotaxis over the entire concentration range to close to background levels and wild type like chemotaxis was recovered following complementation. Real-time PCR studies indicated that the presence of αKG does not modulate mcpK expression. Since αKG is present in plant root exudates it was investigated whether the deletion of mcpK altered maize root colonization. However, no significant changes with respect to the wild type strain were observed. The existence of a chemoreceptor specific for αKG may be due to its central metabolic role as well as to its function as signaling molecule. This work expands the range of known chemoreceptor types and underlines the important physiological role of chemotaxis toward tricarboxylic acid cycle intermediates.
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Affiliation(s)
- David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Alvaro Ortega
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - José A Reyes-Darias
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Vanina García
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Diana López-Farfán
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas Granada, Spain
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Zeng W, Fang F, Liu S, Du G, Chen J, Zhou J. Comparative genomics analysis of a series of Yarrowia lipolytica WSH-Z06 mutants with varied capacity for α-ketoglutarate production. J Biotechnol 2016; 239:76-82. [PMID: 27732868 DOI: 10.1016/j.jbiotec.2016.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/16/2016] [Accepted: 10/07/2016] [Indexed: 01/23/2023]
Abstract
Yarrowia lipolytica is one of the most intensively investigated α-ketoglutaric acid (α-KG) producers, and metabolic engineering has proven effective for enhancing production. However, regulation of α-KG metabolism remains poorly understood. Genetic engineering of new strains is accompanied by potential safety concerns in some countries and regions. A series of mutants with varied capacity for α-KG production were obtained using random mutagenesis of Y. lipolytica WSH-Z06. Comparative genomics analysis was implemented to identify genes candidates associated with α-KG production. Manipulation of genes regulating mitochondrial biogenesis and energy metabolism could improve α-KG production, while genes involved in regulating transformation between keto acids and amino acids may decrease production. One gene associated with cell cycle control well represented in all mutants, whereas this gene involved in cell concentration do not appear to influence α-KG production. The results shed light on α-KG production in eukaryotic cells, and pave the way for a high-throughput screening and random mutagenesis method for enhancing α-KG production.
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Affiliation(s)
- Weizhu Zeng
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Fang Fang
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Song Liu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Guocheng Du
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jian Chen
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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Wheatley NM, Eden KD, Ngo J, Rosinski JS, Sawaya MR, Cascio D, Collazo M, Hoveida H, Hubbell WL, Yeates TO. A PII-Like Protein Regulated by Bicarbonate: Structural and Biochemical Studies of the Carboxysome-Associated CPII Protein. J Mol Biol 2016; 428:4013-4030. [PMID: 27464895 PMCID: PMC5048545 DOI: 10.1016/j.jmb.2016.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/11/2016] [Accepted: 07/18/2016] [Indexed: 11/18/2022]
Abstract
Autotrophic bacteria rely on various mechanisms to increase intracellular concentrations of inorganic forms of carbon (i.e., bicarbonate and CO2) in order to improve the efficiency with which they can be converted to organic forms. Transmembrane bicarbonate transporters and carboxysomes play key roles in accumulating bicarbonate and CO2, but other regulatory elements of carbon concentration mechanisms in bacteria are less understood. In this study, after analyzing the genomic regions around α-type carboxysome operons, we characterize a protein that is conserved across these operons but has not been previously studied. On the basis of a series of apo- and ligand-bound crystal structures and supporting biochemical data, we show that this protein, which we refer to as the carboxysome-associated PII protein (CPII), represents a new and distinct subfamily within the broad superfamily of previously studied PII regulatory proteins, which are generally involved in regulating nitrogen metabolism in bacteria. CPII undergoes dramatic conformational changes in response to ADP binding, and the affinity for nucleotide binding is strongly enhanced by the presence of bicarbonate. CPII therefore appears to be a unique type of PII protein that senses bicarbonate availability, consistent with its apparent genomic association with the carboxysome and its constituents.
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Affiliation(s)
- Nicole M Wheatley
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Kevin D Eden
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Joanna Ngo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Justin S Rosinski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Michael R Sawaya
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Michael Collazo
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Hamidreza Hoveida
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Wayne L Hubbell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Todd O Yeates
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
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Cameron DR, Jiang JH, Kostoulias X, Foxwell DJ, Peleg AY. Vancomycin susceptibility in methicillin-resistant Staphylococcus aureus is mediated by YycHI activation of the WalRK essential two-component regulatory system. Sci Rep 2016; 6:30823. [PMID: 27600558 PMCID: PMC5013275 DOI: 10.1038/srep30823] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/09/2016] [Indexed: 02/01/2023] Open
Abstract
The treatment of infections caused by methicillin-resistant Staphylococcus aureus is complicated by the emergence of strains with intermediate-level resistance to vancomycin (termed VISA). We have characterised a molecular pathway involved in the in vivo evolution of VISA mediated by the regulatory proteins YycH and YycI. In contrast to their function in other bacterial species, we report a positive role for these auxiliary proteins in regulation of the two-component regulator WalRK. Transcriptional profiling of yycH and yycI deletion mutants revealed downregulation of the ‘WalRK regulon’ including cell wall hydrolase genes atlA and sle1, with functional autolysis assays supporting these data by showing an impaired autolytic phenotype for each deletion strain. Using bacterial-two hybrid assays, we showed that YycH and YycI interact, and that YycHI also interacts with the sensor kinase WalK, forming a ternary protein complex. Mutation to YycH or YycI associated with clinical VISA strains had a deleterious impact on the YycHI/WalK complex, suggesting that the interaction is important for the regulation of WalRK. Taken together, we have described a novel antibiotic resistance strategy for the human pathogen S. aureus, whereby YycHI mutations are selected for in vivo leading to reduced WalRK activation, impaired cell wall turnover and ultimately reduced vancomycin efficacy.
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Affiliation(s)
- David R Cameron
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Jhih-Hang Jiang
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Xenia Kostoulias
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Daniel J Foxwell
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Melbourne, Australia.,Department of Infectious Diseases, Alfred Hospital and Monash University, Melbourne, Australia
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Deciphering the Principles of Bacterial Nitrogen Dietary Preferences: a Strategy for Nutrient Containment. mBio 2016; 7:mBio.00792-16. [PMID: 27435461 PMCID: PMC4958250 DOI: 10.1128/mbio.00792-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A fundamental question in microbial physiology concerns why organisms prefer certain nutrients to others. For example, among different nitrogen sources, ammonium is the preferred nitrogen source, supporting fast growth, whereas alternative nitrogen sources, such as certain amino acids, are considered to be poor nitrogen sources, supporting much slower exponential growth. However, the physiological/regulatory logic behind such nitrogen dietary choices remains elusive. In this study, by engineering Escherichia coli, we switched the dietary preferences toward amino acids, with growth rates equivalent to that of the wild-type strain grown on ammonia. However, when the engineered strain was cultured together with wild-type E. coli, this growth advantage was diminished as a consequence of ammonium leakage from the transport-and-catabolism (TC)-enhanced (TCE) cells, which are preferentially utilized by wild-type bacteria. Our results reveal that the nitrogen regulatory (Ntr) system fine tunes the expression of amino acid transport and catabolism components to match the flux through the ammonia assimilation pathway such that essential nutrients are retained, but, as a consequence, the fast growth rate on amino acids is sacrificed. Bacteria exhibit different growth rates under various nutrient conditions. These environmentally related behaviors reflect the coordination between metabolism and the underlying regulatory networks. In the present study, we investigated the intertwined nitrogen metabolic and nitrogen regulatory systems to understand the growth differences between rich and poor nitrogen sources. Although maximal growth rate is considered to be evolutionarily advantageous for bacteria (as remarked by François Jacob, who said that the “dream” of every cell is to become two cells), we showed that negative-feedback loops in the regulatory system inhibit growth rates on amino acids. We demonstrated that in the absence of regulatory feedback, amino acids are capable of supporting fast growth rates, but this results in ammonia leaking out from cells as “waste,” benefiting the growth of competitors. These findings provide important insights into the regulatory logic that controls metabolic flux and ensures nutrient containment but consequently sacrifices growth rate.
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