Base de dados : MEDLINE
Pesquisa : B03.280.200 [Categoria DeCS]
Referências encontradas : 74 [refinar]
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[PMID]:28516845
[Au] Autor:Gründel M; Knoop H; Steuer R
[Ad] Endereço:2​Fachinstitut Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 43, 10115 Berlin, Germany 1​Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestr. 117, 10115 Berlin, Germany.
[Ti] Título:Activity and functional properties of the isocitrate lyase in the cyanobacterium Cyanothece sp. PCC 7424.
[So] Source:Microbiology;163(5):731-744, 2017 May.
[Is] ISSN:1465-2080
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Cyanobacteria are ubiquitous photoautotrophs that assimilate atmospheric CO2 as their main source of carbon. Several cyanobacteria are known to be facultative heterotrophs that are able to grow on diverse carbon sources. For selected strains, assimilation of organic acids and mixotrophic growth on acetate has been reported for decades. However, evidence for the existence of a functional glyoxylate shunt in cyanobacteria has long been contradictory and unclear. Genes coding for isocitrate lyase (ICL) and malate synthase were recently identified in two strains of the genus Cyanothece, and the existence of the complete glyoxylate shunt was verified in a strain of Chlorogloeopsis fritschii. Here, we report that the gene PCC7424_4054 of the strain Cyanothece sp. PCC 7424 encodes an enzymatically active protein that catalyses the reaction of ICL, an enzyme that is specific for the glyoxylate shunt. We demonstrate that ICL activity is induced under alternating day/night cycles and acetate-supplemented cultures exhibit enhanced growth. In contrast, growth under constant light did not result in any detectable ICL activity or enhanced growth of acetate-supplemented cultures. Furthermore, our results indicate that, despite the presence of a glyoxylate shunt, acetate does not support continued heterotrophic growth and cell proliferation. The functional validation of the ICL is supplemented with a bioinformatics analysis of enzymes that co-occur with the glyoxylate shunt. We hypothesize that the glyoxylate shunt in Cyanothece sp. PCC 7424, and possibly other nitrogen-fixing cyanobacteria, is an adaptation to a specific ecological niche and supports assimilation of nitrogen or organic compounds during the night phase.
[Mh] Termos MeSH primário: Acetatos/metabolismo
Cyanothece/enzimologia
Cyanothece/crescimento & desenvolvimento
Glioxilatos/metabolismo
Processos Heterotróficos/genética
Isocitrato Liase/genética
[Mh] Termos MeSH secundário: Proliferação Celular/fisiologia
Cyanothece/genética
Cyanothece/metabolismo
Malato Sintase/genética
Fotoperíodo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Acetates); 0 (Glyoxylates); EC 2.3.3.9 (Malate Synthase); EC 4.1.3.1 (Isocitrate Lyase); JQ39C92HH6 (glyoxylic acid)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171102
[Lr] Data última revisão:
171102
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170519
[St] Status:MEDLINE
[do] DOI:10.1099/mic.0.000459


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[PMID]:27594050
[Au] Autor:Leite JP; Mota R; Durão J; Neves SC; Barrias CC; Tamagnini P; Gales L
[Ad] Endereço:i3S - Instituto de Investigação e Inovação em Saúde, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
[Ti] Título:Cyanobacterium-Derived Extracellular Carbohydrate Polymer for the Controlled Delivery of Functional Proteins.
[So] Source:Macromol Biosci;17(2), 2017 Feb.
[Is] ISSN:1616-5195
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:The unicellular cyanobacterium Cyanothece sp. CCY 0110 is a highly efficient producer of extracellular polymeric substances (EPS), releasing up to 75% of the polymer to the culture medium. The carbohydrate polymer released to the medium (RPS) was previously isolated and characterized; it is composed of nine different monosaccharides including two uronic acids, and also containing peptides and sulfate groups. Here it is shown that the RPS spontaneously assembles with proteins at high concentrations leading to a phase transition. The proteins are released progressively and structurally intact near physiological conditions, primarily through the swelling of the polymer-protein matrix. The releasing kinetics of the proteins can be modulated through the addition of divalent cations, such as calcium. Notably, the polymer is not toxic to human dermal neonatal fibroblasts in vitro at RPS concentrations bellow 0.1 mg mL . The results show that this polymer is a good candidate for the delivery of therapeutic macromolecules.
[Mh] Termos MeSH primário: Carboidratos/química
Cyanothece/química
Espaço Extracelular/química
Proteínas/farmacologia
[Mh] Termos MeSH secundário: Animais
Cátions Bivalentes/farmacologia
Morte Celular/efeitos dos fármacos
Galinhas
Dicroísmo Circular
Preparações de Ação Retardada
Fibroblastos/citologia
Fibroblastos/efeitos dos fármacos
Fibroblastos/metabolismo
Seres Humanos
Hidrodinâmica
Recém-Nascido
Troca Iônica
Ponto Isoelétrico
Peso Molecular
Muramidase/metabolismo
Procainamida
Reologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Carbohydrates); 0 (Cations, Divalent); 0 (Delayed-Action Preparations); 0 (Proteins); EC 3.2.1.17 (Muramidase); L39WTC366D (Procainamide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171013
[Lr] Data última revisão:
171013
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160906
[St] Status:MEDLINE
[do] DOI:10.1002/mabi.201600206


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[PMID]:27841750
[Au] Autor:Bent AF; Mann G; Houssen WE; Mykhaylyk V; Duman R; Thomas L; Jaspars M; Wagner A; Naismith JH
[Ad] Endereço:BSRC, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland.
[Ti] Título:Structure of the cyanobactin oxidase ThcOx from Cyanothece sp. PCC 7425, the first structure to be solved at Diamond Light Source beamline I23 by means of S-SAD.
[So] Source:Acta Crystallogr D Struct Biol;72(Pt 11):1174-1180, 2016 11 01.
[Is] ISSN:2059-7983
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Determination of protein crystal structures requires that the phases are derived independently of the observed measurement of diffraction intensities. Many techniques have been developed to obtain phases, including heavy-atom substitution, molecular replacement and substitution during protein expression of the amino acid methionine with selenomethionine. Although the use of selenium-containing methionine has transformed the experimental determination of phases it is not always possible, either because the variant protein cannot be produced or does not crystallize. Phasing of structures by measuring the anomalous diffraction from S atoms could in theory be almost universal since almost all proteins contain methionine or cysteine. Indeed, many structures have been solved by the so-called native sulfur single-wavelength anomalous diffraction (S-SAD) phasing method. However, the anomalous effect is weak at the wavelengths where data are normally recorded (between 1 and 2 Å) and this limits the potential of this method to well diffracting crystals. Longer wavelengths increase the strength of the anomalous signal but at the cost of increasing air absorption and scatter, which degrade the precision of the anomalous measurement, consequently hindering phase determination. A new instrument, the long-wavelength beamline I23 at Diamond Light Source, was designed to work at significantly longer wavelengths compared with standard synchrotron beamlines in order to open up the native S-SAD method to projects of increasing complexity. Here, the first novel structure, that of the oxidase domain involved in the production of the natural product patellamide, solved on this beamline is reported using data collected to a resolution of 3.15 Šat a wavelength of 3.1 Å. The oxidase is an example of a protein that does not crystallize as the selenium variant and for which no suitable homology model for molecular replacement was available. Initial attempts collecting anomalous diffraction data for native sulfur phasing on a standard macromolecular crystallography beamline using a wavelength of 1.77 Šdid not yield a structure. The new beamline thus has the potential to facilitate structure determination by native S-SAD phasing for what would previously have been regarded as very challenging cases with modestly diffracting crystals and low sulfur content.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Cyanothece/enzimologia
Oxirredutases/química
[Mh] Termos MeSH secundário: Cristalização/métodos
Cristalografia por Raios X/métodos
Cyanothece/química
Modelos Moleculares
Conformação Proteica
Selenometionina/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 964MRK2PEL (Selenomethionine); EC 1.- (Oxidoreductases)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171117
[Lr] Data última revisão:
171117
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161115
[St] Status:MEDLINE


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[PMID]:27742679
[Au] Autor:Sadler NC; Bernstein HC; Melnicki MR; Charania MA; Hill EA; Anderson LN; Monroe ME; Smith RD; Beliaev AS; Wright AT
[Ad] Endereço:Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA.
[Ti] Título:Dinitrogenase-Driven Photobiological Hydrogen Production Combats Oxidative Stress in Cyanothece sp. Strain ATCC 51142.
[So] Source:Appl Environ Microbiol;82(24):7227-7235, 2016 Dec 15.
[Is] ISSN:1098-5336
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Photobiologically synthesized hydrogen (H ) gas is carbon neutral to produce and clean to combust, making it an ideal biofuel. Cyanothece sp. strain ATCC 51142 is a cyanobacterium capable of performing simultaneous oxygenic photosynthesis and H production, a highly perplexing phenomenon because H evolving enzymes are O sensitive. We employed a system-level in vivo chemoproteomic profiling approach to explore the cellular dynamics of protein thiol redox and how thiol redox mediates the function of the dinitrogenase NifHDK, an enzyme complex capable of aerobic hydrogenase activity. We found that NifHDK responds to intracellular redox conditions and may act as an emergency electron valve to prevent harmful reactive oxygen species formation in concert with other cell strategies for maintaining redox homeostasis. These results provide new insight into cellular redox dynamics useful for advancing photolytic bioenergy technology and reveal a new understanding for the biological function of NifHDK. IMPORTANCE: Here, we demonstrate that high levels of hydrogen synthesis can be induced as a protection mechanism against oxidative stress via the dinitrogenase enzyme complex in Cyanothece sp. strain ATCC 51142. This is a previously unknown feature of cyanobacterial dinitrogenase, and we anticipate that it may represent a strategy to exploit cyanobacteria for efficient and scalable hydrogen production. We utilized a chemoproteomic approach to capture the in situ dynamics of reductant partitioning within the cell, revealing proteins and reactive thiols that may be involved in redox sensing and signaling. Additionally, this method is widely applicable across biological systems to achieve a greater understanding of how cells navigate their environment and how redox chemistry can be utilized to alter metabolism and achieve homeostasis.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Cyanothece/enzimologia
Hidrogênio/metabolismo
Nitrogenase/metabolismo
Estresse Oxidativo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Cyanothece/genética
Cyanothece/metabolismo
Cyanothece/efeitos da radiação
Luz
Nitrogenase/genética
Oxirredução
Oxigênio/metabolismo
Fotossíntese/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 7YNJ3PO35Z (Hydrogen); EC 1.18.6.1 (Nitrogenase); S88TT14065 (Oxygen)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171107
[Lr] Data última revisão:
171107
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161016
[St] Status:MEDLINE


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[PMID]:27609420
[Au] Autor:Na S; Payne SH; Bandeira N
[Ad] Endereço:From the ‡Dept. of Computer Science and Engineering, University of California, San Diego, La Jolla, California, 92093.
[Ti] Título:Multi-species Identification of Polymorphic Peptide Variants via Propagation in Spectral Networks.
[So] Source:Mol Cell Proteomics;15(11):3501-3512, 2016 Nov.
[Is] ISSN:1535-9484
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Peptide and protein identification remains challenging in organisms with poorly annotated or rapidly evolving genomes, as are commonly encountered in environmental or biofuels research. Such limitations render tandem mass spectrometry (MS/MS) database search algorithms ineffective as they lack corresponding sequences required for peptide-spectrum matching. We address this challenge with the spectral networks approach to (1) match spectra of orthologous peptides across multiple related species and then (2) propagate peptide annotations from identified to unidentified spectra. We here present algorithms to assess the statistical significance of spectral alignments (Align-GF), reduce the impurity in spectral networks, and accurately estimate the error rate in propagated identifications. Analyzing three related Cyanothece species, a model organism for biohydrogen production, spectral networks identified peptides from highly divergent sequences from networks with dozens of variant peptides, including thousands of peptides in species lacking a sequenced genome. Our analysis further detected the presence of many novel putative peptides even in genomically characterized species, thus suggesting the possibility of gaps in our understanding of their proteomic and genomic expression. A web-based pipeline for spectral networks analysis is available at http://proteomics.ucsd.edu/software.
[Mh] Termos MeSH primário: Cyanothece/metabolismo
Peptídeos/análise
Proteômica/métodos
[Mh] Termos MeSH secundário: Algoritmos
Proteínas de Bactérias/metabolismo
Análise por Conglomerados
Cyanothece/classificação
Bases de Dados de Proteínas
Genoma Bacteriano
Análise de Sequência de Proteína
Software
Espectrometria de Massas em Tandem/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Peptides)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170614
[Lr] Data última revisão:
170614
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160910
[St] Status:MEDLINE


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[PMID]:27402833
[Au] Autor:Matei E; Basu R; Furey W; Shi J; Calnan C; Aiken C; Gronenborn AM
[Ad] Endereço:From the Department of Structural Biology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15260.
[Ti] Título:Structure and Glycan Binding of a New Cyanovirin-N Homolog.
[So] Source:J Biol Chem;291(36):18967-76, 2016 09 02.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The HIV-1 envelope glycoprotein gp120 is heavily glycosylated and bears numerous high mannose sugars. These sugars can serve as targets for HIV-inactivating compounds, such as antibodies and lectins, which bind to the glycans and interfere with viral entry into the target cell. We determined the 1.6 Å x-ray structure of Cyt-CVNH, a recently identified lectin from the cyanobacterium Cyanothece(7424), and elucidated its glycan specificity by NMR. The Cyt-CVNH structure and glycan recognition profile are similar to those of other CVNH proteins, with each domain specifically binding to Manα(1-2)Manα units on the D1 and D3 arms of high mannose glycans. However, in contrast to CV-N, no cross-linking and precipitation of the cross-linked species in solution was observed upon Man-9 binding, allowing, for the first time, investigation of the interaction of Man-9 with a member of the CVNH family by NMR. HIV assays showed that Cyt-CVNH is able to inhibit HIV-1 with ∼4-fold higher potency than CV-N(P51G), a stabilized version of wild type CV-N. Therefore, Cyt-CVNH may qualify as a valuable lectin for potential microbicidal use.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Proteínas de Transporte/química
Cyanothece/química
Lectinas de Ligação a Manose/química
Manose/química
[Mh] Termos MeSH secundário: Linhagem Celular
Cristalografia por Raios X
Proteína gp120 do Envelope de HIV/metabolismo
Infecções por HIV/tratamento farmacológico
Infecções por HIV/metabolismo
HIV-1/metabolismo
Seres Humanos
Masculino
Manose/metabolismo
Lectinas de Ligação a Manose/farmacologia
Ligação Proteica
Homologia Estrutural de Proteína
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Carrier Proteins); 0 (HIV Envelope Protein gp120); 0 (Mannose-Binding Lectins); 0 (gp120 protein, Human immunodeficiency virus 1); 184539-38-6 (cyanovirin N); PHA4727WTP (Mannose)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171124
[Lr] Data última revisão:
171124
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160713
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M116.740415


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[PMID]:27188779
[Au] Autor:Mota R; Rossi F; Andrenelli L; Pereira SB; De Philippis R; Tamagnini P
[Ad] Endereço:i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
[Ti] Título:Released polysaccharides (RPS) from Cyanothece sp. CCY 0110 as biosorbent for heavy metals bioremediation: interactions between metals and RPS binding sites.
[So] Source:Appl Microbiol Biotechnol;100(17):7765-75, 2016 Sep.
[Is] ISSN:1432-0614
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Bioremediation of heavy metals using microorganisms can be advantageous compared to conventional physicochemical methods due to the use of renewable resources and efficiencies of removal particularly cations at low concentrations. In this context, cyanobacteria/cyanobacterial extracellular polymeric substances (EPS) emerge as a valid alternative due to the anionic nature and particular composition of these polymers. In this work, various culture fractions of the unicellular cyanobacterium Cyanothece sp. CCY 0110 were employed in bioremoval assays using three of the most common heavy metal pollutants in water bodies-copper, cadmium, and lead-separately or in combined systems. Our study showed that the released polysaccharides (RPS) were the most efficient fraction, removing the metal(s) by biosorption. Therefore, this polymer was subsequently used to evaluate the interactions between the metals/RPS binding sites using SEM-EDX, ICP-OES, and FTIR. Acid and basic pretreatments applied to the polymer further improve the process efficiency, and the exposure to an alkaline solution seems to alter the RPS conformation. The differences observed in the specific metal bioremoval seem to be mainly due to the RPS organic functional groups available, mainly carboxyl and hydroxyl, than to an ion exchange mechanism. Considering that Cyanothece is a highly efficient RPS-producer and that RPS can be easily separated from the culture, immobilized or confined, this polymer can be advantageous for the establishment/improvement of heavy metal removal systems.
[Mh] Termos MeSH primário: Biodegradação Ambiental
Cádmio/metabolismo
Cobre/metabolismo
Cyanothece/metabolismo
Chumbo/metabolismo
Metais Pesados/metabolismo
Polissacarídeos Bacterianos/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
Polissacarídeos Bacterianos/secreção
Poluentes Químicos da Água/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Metals, Heavy); 0 (Polysaccharides, Bacterial); 0 (Water Pollutants, Chemical); 00BH33GNGH (Cadmium); 2P299V784P (Lead); 789U1901C5 (Copper)
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170227
[Lr] Data última revisão:
170227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160519
[St] Status:MEDLINE
[do] DOI:10.1007/s00253-016-7602-9


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[PMID]:26832735
[Au] Autor:Newie J; Kasanmascheff M; Bennati M; Feussner I
[Ad] Endereço:Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University, Justus-von-Liebig Weg 11, 37077, Göttingen, Germany.
[Ti] Título:Kinetics of Bis-Allylic Hydroperoxide Synthesis in the Iron-Containing Lipoxygenase 2 from Cyanothece and the Effects of Manganese Substitution.
[So] Source:Lipids;51(3):335-47, 2016 Mar.
[Is] ISSN:1558-9307
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Lipoxygenases (LOX) catalyze the regio- and stereospecific insertion of dioxygen into polyunsaturated fatty acids. While the catalytic metal of LOX is typically a non-heme iron, some fungal LOX contain manganese as catalytic metal (MnLOX). In general, LOX insert dioxygen at C9 or C13 of linoleic acid leading to the formation of conjugated hydroperoxides. MnLOX (EC 1.13.11.45), however, catalyze the oxygen insertion also at C11, resulting in bis-allylic hydroperoxides. Interestingly, the iron-containing CspLOX2 (EC 1.13.11.B6) from Cyanothece PCC8801 also produces bis-allylic hydroperoxides. What role the catalytic metal plays and how this unusual reaction is catalyzed by either MnLOX or CspLOX2 is not understood. Our findings suggest that only iron is the catalytically active metal in CspLOX2. The enzyme loses its catalytic activity almost completely when iron is substituted with manganese, suggesting that the catalytic metal is not interchangeable. Using kinetic and spectroscopic approaches, we further found that first a mixture of bis-allylic and conjugated hydroperoxy products is formed. This is followed by the isomerization of the bis-allylic product to conjugated products at a slower rate. These results suggest that MnLOX and CspLOX2 share a very similar reaction mechanism and that LOX with a Fe or Mn cofactor have the potential to form bis-allylic products. Therefore, steric factors are probably responsible for this unusual specificity. As CspLOX2 is the LOX with the highest proportion of the bis-allylic product known so far, it will be an ideal candidate for further structural analysis to understand the molecular basis of the formation of bis-allylic hydroperoxides.
[Mh] Termos MeSH primário: Cyanothece/enzimologia
Peróxido de Hidrogênio/química
Peróxido de Hidrogênio/metabolismo
Ferro/metabolismo
Lipoxigenase/química
Lipoxigenase/metabolismo
Manganês/metabolismo
[Mh] Termos MeSH secundário: Cyanothece/metabolismo
Cinética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
42Z2K6ZL8P (Manganese); BBX060AN9V (Hydrogen Peroxide); E1UOL152H7 (Iron); EC 1.13.11.12 (Lipoxygenase)
[Em] Mês de entrada:1612
[Cu] Atualização por classe:171105
[Lr] Data última revisão:
171105
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160203
[St] Status:MEDLINE
[do] DOI:10.1007/s11745-016-4127-z


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[PMID]:26781249
[Au] Autor:Klemke F; Nürnberg DJ; Ziegler K; Beyer G; Kahmann U; Lockau W; Volkmer T
[Ad] Endereço:1​ Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestraße 117, 10115 Berlin, Germany.
[Ti] Título:CphA2 is a novel type of cyanophycin synthetase in N2-fixing cyanobacteria.
[So] Source:Microbiology;162(3):526-36, 2016 Mar.
[Is] ISSN:1465-2080
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Most cyanobacteria use a single type of cyanophycin synthetase, CphA1, to synthesize the nitrogen-rich polymer cyanophycin. The genomes of many N2-fixing cyanobacteria contain an additional gene that encodes a second type of cyanophycin synthetase, CphA2. The potential function of this enzyme has been debated due to its reduced size and the lack of one of the two ATP-binding sites that are present in CphA1. Here, we analysed CphA2 from Anabaena variabilis ATCC 29413 and Cyanothece sp. PCC 7425. We found that CphA2 polymerized the dipeptide ß-aspartyl-arginine to form cyanophycin. Thus, CphA2 represents a novel type of cyanophycin synthetase. A cphA2 disruption mutant of A. variabilis was generated. Growth of this mutant was impaired under high-light conditions and nitrogen deprivation, suggesting that CphA2 plays an important role in nitrogen metabolism under N2-fixing conditions. Electron micrographs revealed that the mutant had fewer cyanophycin granules, but no alteration in the distribution of granules in its cells was observed. Localization of CphA2 by immunogold electron microscopy demonstrated that the enzyme is attached to cyanophycin granules. Expression of CphA1 and CphA2 was examined in Anabaena WT and cphA mutant cells. Whilst the CphA1 level increased upon nitrogen deprivation, the CphA2 level remained nearly constant.
[Mh] Termos MeSH primário: Anabaena variabilis/enzimologia
Anabaena variabilis/metabolismo
Proteínas de Bactérias/biossíntese
Proteínas de Bactérias/metabolismo
Cyanothece/enzimologia
Cyanothece/metabolismo
Peptídeo Sintases/metabolismo
[Mh] Termos MeSH secundário: Anabaena variabilis/genética
Anabaena variabilis/crescimento & desenvolvimento
Proteínas de Bactérias/genética
Dipeptídeos/metabolismo
Técnicas de Inativação de Genes
Luz
Nitrogênio/metabolismo
Peptídeo Sintases/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Dipeptides); 0 (cyanophycin); EC 6.3.2.- (Peptide Synthases); EC 6.3.2.- (cyanophycin synthase, bacteria); N762921K75 (Nitrogen)
[Em] Mês de entrada:1612
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160120
[St] Status:MEDLINE
[do] DOI:10.1099/mic.0.000241


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[PMID]:26692191
[Au] Autor:Mueller TJ; Welsh EA; Pakrasi HB; Maranas CD
[Ad] Endereço:Department of Chemical Engineering, Pennsylvania State University , University Park, Pennsylvania 16801, United States.
[Ti] Título:Identifying Regulatory Changes to Facilitate Nitrogen Fixation in the Nondiazotroph Synechocystis sp. PCC 6803.
[So] Source:ACS Synth Biol;5(3):250-8, 2016 Mar 18.
[Is] ISSN:2161-5063
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The incorporation of biological nitrogen fixation into a nondiazotrophic photosynthetic organism provides a promising solution to the increasing fixed nitrogen demand, but is accompanied by a number of challenges for accommodating two incompatible processes within the same organism. Here we present regulatory influence networks for two cyanobacteria, Synechocystis PCC 6803 and Cyanothece ATCC 51142, and evaluate them to co-opt native transcription factors that may be used to control the nif gene cluster once it is transferred to Synechocystis. These networks were further examined to identify candidate transcription factors for other metabolic processes necessary for temporal separation of photosynthesis and nitrogen fixation, glycogen catabolism and cyanophycin synthesis. Two transcription factors native to Synechocystis, LexA and Rcp1, were identified as promising candidates for the control of the nif gene cluster and other pertinent metabolic processes, respectively. Lessons learned in the incorporation of nitrogen fixation into a nondiazotrophic prokaryote may be leveraged to further progress the incorporation of nitrogen fixation in plants.
[Mh] Termos MeSH primário: Fixação de Nitrogênio/genética
Synechocystis/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Cyanothece/metabolismo
Regulação Bacteriana da Expressão Gênica
Redes Reguladoras de Genes/genética
Família Multigênica
Nitrogênio/metabolismo
Serina Endopeptidases/genética
Fatores de Transcrição/genética
Fatores de Transcrição/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (LexA protein, Bacteria); 0 (Rcp1 protein, Synechocystis); 0 (Transcription Factors); EC 3.4.21.- (Serine Endopeptidases); N762921K75 (Nitrogen)
[Em] Mês de entrada:1612
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151223
[St] Status:MEDLINE
[do] DOI:10.1021/acssynbio.5b00202



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