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Pesquisa : D08.811.520.232.400.850 [Categoria DeCS]
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[PMID]:28465237
[Au] Autor:Sharma R; Keshari D; Singh KS; Singh SK
[Ad] Endereço:Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India.
[Ti] Título:Biochemical and functional characterization of MRA_1571 of Mycobacterium tuberculosis H37Ra and effect of its down-regulation on survival in macrophages.
[So] Source:Biochem Biophys Res Commun;487(4):892-897, 2017 06 10.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Amino acid biosynthesis has emerged as a source of new drug targets as many bacterial strains auxotrophic for amino acids fail to proliferate under in vivo conditions. Branch chain amino acids (BCAAs) are important for Mycobacterium tuberculosis (Mtb) survival and strains deficient in their biosynthesis were attenuated for growth in mice. Threonine dehydratase (IlvA) is a pyridoxal-5-phosphate (PLP) dependent enzyme that catalyzes the first step in isoleucine biosynthesis. The MRA_1571 of Mycobacterium tuberculosis H37Ra (Mtb-Ra), annotated to be coding for IlvA, was cloned, expressed and purified. Purified protein was subsequently used for developing enzyme assay and to study its biochemical properties. Also, E. coli BL21 (DE3) IlvA knockout (E. coli-ΔilvA) was developed and genetically complemented with Mtb-Ra ilvA expression construct (pET32a-ilvA) to make complemented E. coli strain (E. coli-ΔilvA + pET32a-ilvA). The E. coli-ΔilvA showed growth failure in minimal medium but growth restoration was observed in E. coli-ΔilvA + pET32a-ilvA. E. coli-ΔilvA growth was also restored in the presence of isoleucine. The IlvA localization studies detected its distribution in cell wall and membrane fractions with relatively minor presence in cytosolic fraction. Maximum IlvA expression was observed at 72 h in wild-type (WT) Mtb-Ra infecting macrophages. Also, Mtb-Ra IlvA knockdown (KD) showed reduced survival in macrophages compared to WT and complemented strain (KDC).
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Regulação para Baixo
Macrófagos/metabolismo
Macrófagos/microbiologia
Mycobacterium tuberculosis/enzimologia
Mycobacterium tuberculosis/metabolismo
Treonina Desidratase/metabolismo
[Mh] Termos MeSH secundário: Animais
Proteínas de Bactérias/química
Células Cultivadas
Camundongos
Treonina Desidratase/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171128
[Lr] Data última revisão:
171128
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE


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[PMID]:28335772
[Au] Autor:Weber N; Hatsch A; Labagnere L; Heider H
[Ad] Endereço:Evolva SA, Duggingerstrasse 23, 4153, Reinach, Switzerland. noraw@evolva.com.
[Ti] Título:Production of (S)-2-aminobutyric acid and (S)-2-aminobutanol in Saccharomyces cerevisiae.
[So] Source:Microb Cell Fact;16(1):51, 2017 Mar 23.
[Is] ISSN:1475-2859
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Saccharomyces cerevisiae (baker's yeast) has great potential as a whole-cell biocatalyst for multistep synthesis of various organic molecules. To date, however, few examples exist in the literature of the successful biosynthetic production of chemical compounds, in yeast, that do not exist in nature. Considering that more than 30% of all drugs on the market are purely chemical compounds, often produced by harsh synthetic chemistry or with very low yields, novel and environmentally sound production routes are highly desirable. Here, we explore the biosynthetic production of enantiomeric precursors of the anti-tuberculosis and anti-epilepsy drugs ethambutol, brivaracetam, and levetiracetam. To this end, we have generated heterologous biosynthetic pathways leading to the production of (S)-2-aminobutyric acid (ABA) and (S)-2-aminobutanol in baker's yeast. RESULTS: We first designed a two-step heterologous pathway, starting with the endogenous amino acid L-threonine and leading to the production of enantiopure (S)-2-aminobutyric acid. The combination of Bacillus subtilis threonine deaminase and a mutated Escherichia coli glutamate dehydrogenase resulted in the intracellular accumulation of 0.40 mg/L of (S)-2-aminobutyric acid. The combination of a threonine deaminase from Solanum lycopersicum (tomato) with two copies of mutated glutamate dehydrogenase from E. coli resulted in the accumulation of comparable amounts of (S)-2-aminobutyric acid. Additional L-threonine feeding elevated (S)-2-aminobutyric acid production to more than 1.70 mg/L. Removing feedback inhibition of aspartate kinase HOM3, an enzyme involved in threonine biosynthesis in yeast, elevated (S)-2-aminobutyric acid biosynthesis to above 0.49 mg/L in cultures not receiving additional L-threonine. We ultimately extended the pathway from (S)-2-aminobutyric acid to (S)-2-aminobutanol by introducing two reductases and a phosphopantetheinyl transferase. The engineered strains produced up to 1.10 mg/L (S)-2-aminobutanol. CONCLUSIONS: Our results demonstrate the biosynthesis of (S)-2-aminobutyric acid and (S)-2-aminobutanol in yeast. To our knowledge this is the first time that the purely synthetic compound (S)-2-aminobutanol has been produced in vivo. This work paves the way to greener and more sustainable production of chemical entities hitherto inaccessible to synthetic biology.
[Mh] Termos MeSH primário: Aminobutiratos/química
Vias Biossintéticas/genética
Butanóis/metabolismo
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/metabolismo
[Mh] Termos MeSH secundário: Aminobutiratos/metabolismo
Antituberculosos/química
Escherichia coli/química
Escherichia coli/citologia
Escherichia coli/genética
Escherichia coli/metabolismo
Etambutol/química
Glutamato Desidrogenase/genética
Glutamato Desidrogenase/metabolismo
Lycopersicon esculentum/genética
Engenharia Metabólica/métodos
Saccharomyces cerevisiae/química
Treonina/metabolismo
Treonina Desidratase/genética
Treonina Desidratase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Aminobutyrates); 0 (Antitubercular Agents); 0 (Butanols); 2ZD004190S (Threonine); 8306QPJ19P (alpha-aminobutyric acid); 8G167061QZ (Ethambutol); EC 1.4.1.2 (Glutamate Dehydrogenase); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170424
[Lr] Data última revisão:
170424
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170325
[St] Status:MEDLINE
[do] DOI:10.1186/s12934-017-0667-z


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[PMID]:27260660
[Au] Autor:Rosenberg J; Müller P; Lentes S; Thiele MJ; Zeigler DR; Tödter D; Paulus H; Brantl S; Stülke J; Commichau FM
[Ad] Endereço:Department of General Microbiology, Georg August University Göttingen, Grisebachstr. 8, Göttingen, 37077, Germany.
[Ti] Título:ThrR, a DNA-binding transcription factor involved in controlling threonine biosynthesis in Bacillus subtilis.
[So] Source:Mol Microbiol;101(5):879-93, 2016 Sep.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The threonine dehydratase IlvA is part of the isoleucine biosynthesis pathway in the Gram-positive model bacterium Bacillus subtilis. Consequently, deletion of ilvA causes isoleucine auxotrophy. It has been reported that ilvA pseudo-revertants having a derepressed hom-thrCB operon appear in the presence of threonine. Here we have characterized two classes of ilvA pseudo-revertants. In the first class the hom-thrCB operon was derepressed unmasking the threonine dehydratase activity of the threonine synthase ThrC. In the second class of mutants, threonine biosynthesis was more broadly affected. The first class of ilvA pseudo-revertants had a mutation in the Phom promoter (P*hom ), resulting in constitutive expression of the hom-thrCB operon. In the second class of ilvA pseudo-revertants, the thrR gene encoding a putative DNA-binding protein was inactivated, also resulting in constitutive expression of the hom-thrCB operon. Here we demonstrate that ThrR is indeed a DNA-binding transcription factor that regulates the hom-thrCB operon and the thrD aspartokinase gene. DNA binding assays uncovered the DNA-binding site of ThrR and revealed that the repressor competes with the RNA polymerase for DNA binding. This study also revealed that ThrR orthologs are ubiquitous in genomes from the Gram-positive phylum Firmicutes and in some Gram-negative bacteria.
[Mh] Termos MeSH primário: Bacillus subtilis/metabolismo
Treonina Desidratase/metabolismo
Treonina/biossíntese
[Mh] Termos MeSH secundário: Ácido Aspártico/metabolismo
Bacillus subtilis/genética
Sequência de Bases
Carbono-Oxigênio Liases/metabolismo
DNA/genética
Proteínas de Ligação a DNA/metabolismo
Escherichia coli/genética
Genes Bacterianos
Mutação
Óperon
Regiões Promotoras Genéticas
Treonina/metabolismo
Treonina Desidratase/genética
Fatores de Transcrição/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (DNA-Binding Proteins); 0 (Transcription Factors); 2ZD004190S (Threonine); 30KYC7MIAI (Aspartic Acid); 9007-49-2 (DNA); EC 4.2.- (Carbon-Oxygen Lyases); EC 4.2.3.1 (threonine synthase); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170714
[Lr] Data última revisão:
170714
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160605
[St] Status:MEDLINE
[do] DOI:10.1111/mmi.13429


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[PMID]:26917255
[Au] Autor:Zhang C; Qi J; Li Y; Fan X; Xu Q; Chen N; Xie X
[Ad] Endereço:National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin, P. R. China.
[Ti] Título:Production of α-ketobutyrate using engineered Escherichia coli via temperature shift.
[So] Source:Biotechnol Bioeng;113(9):2054-9, 2016 Sep.
[Is] ISSN:1097-0290
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Alpha-ketobutyrate has been widely used in medicine and food additive industry. Because chemical and enzymatic methods are associated with many deficiencies, the recent focus shifted to fermentation for the production of α-ketobutyrate. In this study, a genetically engineered strain THRDΔrhtAΔilvIH/pWSK29-ilvA was constructed, starting from an L-threonine-producing strain, by overexpressing threonine dehydratase (TD), reducing α-ketobutyrate catabolism and L-threonine export. The shake flask cultivation of THRDΔrhtAΔilvIH/pWSK29-ilvA allowed the production of 16.2 g/L α-ketobutyrate. Accumulation of α-ketobutyrate severely inhibited the cell growth. To develop a better TD expression system and avoid the usage of the expensive inducer IPTG, a temperature-induced plasmid pBV220-ilvA was selected to transform the strain THRDΔrhtAΔilvIH for α-ketobutyrate production. The initial temperature was maintained at 35°C to guarantee normal cell growth, and then elevated to 40°C to induce the expression of TD. Under optimized conditions, the α-ketobutyrate titer reached 40.8 g/L after 28 h of fermentation, with a productivity of 1.46 g/L/h and a yield of 0.19 g/g glucose, suggesting large-scale production potential. Biotechnol. Bioeng. 2016;113: 2054-2059. © 2016 Wiley Periodicals, Inc.
[Mh] Termos MeSH primário: Butiratos/metabolismo
Escherichia coli/metabolismo
Escherichia coli/fisiologia
Engenharia Metabólica/métodos
[Mh] Termos MeSH secundário: Técnicas de Cultura Celular por Lotes
Butiratos/análise
Escherichia coli/genética
Fermentação
Redes e Vias Metabólicas
Temperatura Ambiente
Treonina Desidratase
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Butyrates); 600-18-0 (alpha-ketobutyric acid); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171006
[Lr] Data última revisão:
171006
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160227
[St] Status:MEDLINE
[do] DOI:10.1002/bit.25959


  5 / 315 MEDLINE  
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[PMID]:26733068
[Au] Autor:Bazurto JV; Farley KR; Downs DM
[Ad] Endereço:Department of Microbiology, University of Georgia, Athens, Georgia, USA.
[Ti] Título:An Unexpected Route to an Essential Cofactor: Escherichia coli Relies on Threonine for Thiamine Biosynthesis.
[So] Source:MBio;7(1):e01840-15, 2016 Jan 05.
[Is] ISSN:2150-7511
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:UNLABELLED: Metabolism consists of biochemical reactions that are combined to generate a robust metabolic network that can respond to perturbations and also adapt to changing environmental conditions. Escherichia coli and Salmonella enterica are closely related enterobacteria that share metabolic components, pathway structures, and regulatory strategies. The synthesis of thiamine in S. enterica has been used to define a node of the metabolic network by analyzing alternative inputs to thiamine synthesis from diverse metabolic pathways. To assess the conservation of metabolic networks in organisms with highly conserved components, metabolic contributions to thiamine synthesis in E. coli were investigated. Unexpectedly, we found that, unlike S. enterica, E. coli does not use the phosphoribosylpyrophosphate (PRPP) amidotransferase (PurF) as the primary enzyme for synthesis of phosphoribosylamine (PRA). In fact, our data showed that up to 50% of the PRA used by E. coli to make thiamine requires the activities of threonine dehydratase (IlvA) and anthranilate synthase component II (TrpD). Significantly, the IlvA- and TrpD-dependent pathway to PRA functions in S. enterica only in the absence of a functional reactive intermediate deaminase (RidA) enzyme, bringing into focus how these closely related bacteria have distinct metabolic networks. IMPORTANCE: In most bacteria, including Salmonella strains and Escherichia coli, synthesis of the pyrimidine moiety of the essential coenzyme, thiamine pyrophosphate (TPP), shares enzymes with the purine biosynthetic pathway. Phosphoribosylpyrophosphate amidotransferase, encoded by the purF gene, generates phosphoribosylamine (PRA) and is considered the first enzyme in the biosynthesis of purines and the pyrimidine moiety of TPP. We show here that, unlike Salmonella, E. coli synthesizes significant thiamine from PRA derived from threonine using enzymes from the isoleucine and tryptophan biosynthetic pathways. These data show that two closely related organisms can have distinct metabolic network structures despite having similar enzyme components, thus emphasizing caveats associated with predicting metabolic potential from genome content.
[Mh] Termos MeSH primário: Vias Biossintéticas/genética
Escherichia coli/genética
Escherichia coli/metabolismo
Tiamina/biossíntese
Treonina/metabolismo
[Mh] Termos MeSH secundário: Antranilato Sintase/metabolismo
Transferases de Grupos Nitrogenados/metabolismo
Ribosemonofosfatos/metabolismo
Salmonella enterica/genética
Salmonella enterica/metabolismo
Treonina Desidratase/metabolismo
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Ribosemonophosphates); 14050-66-9 (phosphoribosylamine); 2ZD004190S (Threonine); EC 2.6.- (Nitrogenous Group Transferases); EC 4.1.3.27 (Anthranilate Synthase); EC 4.1.3.27 (anthranilate synthase, glutamine amidotransferase subunit); EC 4.3.1.19 (Threonine Dehydratase); X66NSO3N35 (Thiamine)
[Em] Mês de entrada:1610
[Cu] Atualização por classe:170330
[Lr] Data última revisão:
170330
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160107
[St] Status:MEDLINE


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[PMID]:26412446
[Au] Autor:Rausher MD; Huang J
[Ad] Endereço:Department of Biology, Duke University mrausher@duke.edu.
[Ti] Título:Prolonged Adaptive Evolution of a Defensive Gene in the Solanaceae.
[So] Source:Mol Biol Evol;33(1):143-51, 2016 Jan.
[Is] ISSN:1537-1719
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Although plants and their natural enemies may coevolve for prolonged periods, little is known about how long individual plant defensive genes are involved in the coevolutionary process. We address this issue by examining patterns of selection on the defensive gene threonine deaminase (TD). Tomato (Solanum lycopersicum) has two copies of this gene. One performs the canonical housekeeping function in amino acid metabolism of catalyzing the first reaction in the conversion of threonine to isoleucine. The second copy functions as an antinutritive defense against lepidopteran herbivores by depleting threonine in the insect gut. Wild tobacco (Nicotiana attenuata) also contains a defensive copy. We show that a single copy of TD underwent two or three duplications near the base of the Solanaceae. One copy retains the housekeeping function, whereas a second copy evolved defensive functions. Positive selection occurred on the branch of the TD2 gene tree subtending the common ancestor of the Nicotianoideae and Solanoideae. It also occurred within the Solanoideae clade but not within the Nicotianoideae clade. Finally, it occurred on most branches leading from the common ancestor to S. lycopersicum. Based on recent calibrations of the Solanaceae phylogeny, TD2 experienced adaptive substitutions for a period of 30-50 My. We suggest that the most likely explanation for this result is fluctuating herbivore abundances: When herbivores are rare, relaxed selection increases the likelihood that slightly disadvantageous mutations will be fixed by drift; when herbivores are common, increased selection causes the evolution of compensatory adaptive mutations. Alternative explanations are also discussed.
[Mh] Termos MeSH primário: Lycopersicon esculentum/genética
Lycopersicon esculentum/fisiologia
Proteínas de Plantas/genética
Treonina Desidratase/genética
[Mh] Termos MeSH secundário: Domínio Catalítico
Evolução Molecular
Duplicação Gênica/genética
Mutação
Filogenia
Treonina Desidratase/classificação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Plant Proteins); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1609
[Cu] Atualização por classe:151230
[Lr] Data última revisão:
151230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150929
[St] Status:MEDLINE
[do] DOI:10.1093/molbev/msv205


  7 / 315 MEDLINE  
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[PMID]:26376640
[Au] Autor:Xu G; Jiang Y; Tao R; Wang S; Zeng H; Yang S
[Ad] Endereço:College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, China.
[Ti] Título:A recyclable biotransformation system for L-2-aminobutyric acid production based on immobilized enzyme technology.
[So] Source:Biotechnol Lett;38(1):123-9, 2016 Jan.
[Is] ISSN:1573-6776
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: To make the previously developed biosynthesis of L-2-aminobutyric acid (L-ABA) more suitable for the industrial-scale production. RESULTS: A recyclable biotransformation system was developed based on immobilized enzyme technology. The conversion yield of L-threonine (at 90 g l(-1)) reached 99.9 % and the theoretical yield of L-ABA reached more than 90 % using the optimized biotransformation system by the individual immobilization of threonine deaminase and the co-immobilization of L leucine dehydrogenase and formate dehydrogenase. 90 g L-threonine l(-1) was converted to 73.9 g L-ABA l(-1) >95 % theoretical yield, within 120-145 min in 30 batch transformation experiments. CONCLUSION: The recyclable biotransformation system is promising to fulfill industrial requirements for L-ABA production.
[Mh] Termos MeSH primário: Aminobutiratos/metabolismo
Leucina Desidrogenase/metabolismo
Treonina Desidratase/metabolismo
[Mh] Termos MeSH secundário: Biotransformação
Enzimas Imobilizadas
Reutilização de Equipamento/economia
Escherichia coli/metabolismo
Leucina Desidrogenase/isolamento & purificação
Treonina Desidratase/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Aminobutyrates); 0 (Enzymes, Immobilized); 8306QPJ19P (alpha-aminobutyric acid); EC 1.4.1.9 (Leucine Dehydrogenase); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1610
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150918
[St] Status:MEDLINE
[do] DOI:10.1007/s10529-015-1957-3


  8 / 315 MEDLINE  
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[PMID]:26070433
[Au] Autor:Guo Y; Xu J; Han M; Zhang W
[Ad] Endereço:Department of Life Sciences, Heze University, Heze, China.
[Ti] Título:Generation of mutant threonine dehydratase and its effects on isoleucine synthesis in Corynebacterium glutamicum.
[So] Source:World J Microbiol Biotechnol;31(9):1369-77, 2015 Sep.
[Is] ISSN:1573-0972
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Isoleucine synthesis is strongly regulated by its end product (isoleucine) in Corynebacterium glutamicum, especially at threonine dehydratase (TD) node. Multiple alignments of TD sequences of C. glutamicum and other sources were performed. According to the structural analysis, three TD variants were constructed by site-directed mutagenesis. These TD variants improved the performance of the holoenzyme. The specific activity of V140M variant was 1.5-fold higher than that of the wild-type TD, whereas F383A variant showed complete resistance to feedback inhibition by isoleucine. V140M-F383A variant had all the advantages of V140M and F383A variants and displayed 1.5-fold specific activity and complete resistance to isoleucine. In C. glutamicum, overexpression of V140M, F383A, and V140M-F383A variants accumulated 0.55, 0.63, and 0.73 g/l isoleucine, and overexpression of wild-type TD produced 0.47 g/l isoleucine. Thus, these novel TD variants, particularly V140M-F383A, showed great potential in isoleucine synthesis.
[Mh] Termos MeSH primário: Corynebacterium glutamicum/metabolismo
Isoleucina/biossíntese
Mutação
Treonina Desidratase/genética
Treonina Desidratase/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Corynebacterium glutamicum/genética
Seres Humanos
Engenharia de Proteínas/métodos
Alinhamento de Sequência
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 04Y7590D77 (Isoleucine); EC 4.3.1.19 (Threonine Dehydratase)
[Em] Mês de entrada:1605
[Cu] Atualização por classe:171102
[Lr] Data última revisão:
171102
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150614
[St] Status:MEDLINE
[do] DOI:10.1007/s11274-015-1885-3


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[PMID]:25301583
[Au] Autor:Vogt M; Krumbach K; Bang WG; van Ooyen J; Noack S; Klein B; Bott M; Eggeling L
[Ad] Endereço:Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich GmbH, Jülich, Germany.
[Ti] Título:The contest for precursors: channelling L-isoleucine synthesis in Corynebacterium glutamicum without byproduct formation.
[So] Source:Appl Microbiol Biotechnol;99(2):791-800, 2015 Jan.
[Is] ISSN:1432-0614
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:L-Isoleucine is an essential amino acid, which is required as a pharma product and feed additive. Its synthesis shares initial steps with that of L-lysine and L-threonine, and four enzymes of L-isoleucine synthesis have an enlarged substrate specificity involved also in L-valine and L-leucine synthesis. As a consequence, constructing a strain specifically overproducing L-isoleucine without byproduct formation is a challenge. Here, we analyze for consequences of plasmid-encoded genes in Corynebacterium glutamicum MH20-22B on L-isoleucine formation, but still obtain substantial accumulation of byproducts. In a different approach, we introduce point mutations into the genome of MH20-22B to remove the feedback control of homoserine dehydrogenase, hom, and threonine dehydratase, ilvA, and we assay sets of genomic promoter mutations to increase hom and ilvA expression as well as to reduce dapA expression, the latter gene encoding the dihydrodipicolinate synthase. The promoter mutations are mirrored in the resulting differential protein levels determined by a targeted LC-MS/MS approach for the three key enzymes. The best combination of genomic mutations was found in strain K2P55, where 53 mM L-isoleucine could be obtained. Whereas in fed-batch fermentations with the plasmid-based strain, 94 mM L-isoleucine with L-lysine as byproduct was formed; with the plasmid-less strain K2P55, 109 mM L-isoleucine accumulated with no substantial byproduct formation. The specific molar yield with the latter strain was 0.188 mol L-isoleucine (mol glucose)(-1) which characterizes it as one of the best L-isoleucine producers available and which does not contain plasmids.
[Mh] Termos MeSH primário: Corynebacterium glutamicum/genética
Corynebacterium glutamicum/metabolismo
Isoleucina/biossíntese
[Mh] Termos MeSH secundário: Cromatografia Líquida
Meios de Cultura
Fermentação
Homosserina Desidrogenase/genética
Homosserina Desidrogenase/metabolismo
Hidroliases/genética
Hidroliases/metabolismo
Concentração de Íons de Hidrogênio
Plasmídeos/genética
Regiões Promotoras Genéticas
Espectrometria de Massas em Tandem
Treonina Desidratase/genética
Treonina Desidratase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Culture Media); 04Y7590D77 (Isoleucine); EC 1.1.1.3 (Homoserine Dehydrogenase); EC 4.2.1.- (Hydro-Lyases); EC 4.3.1.19 (Threonine Dehydratase); EC 4.3.3.7 (4-hydroxy-tetrahydrodipicolinate synthase)
[Em] Mês de entrada:1510
[Cu] Atualização por classe:151119
[Lr] Data última revisão:
151119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141011
[St] Status:MEDLINE
[do] DOI:10.1007/s00253-014-6109-5


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[PMID]:25129826
[Au] Autor:Liu X; Xu J; Wang J; Ji F; Yin X; Shi J
[Ad] Endereço:Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base/Key Laboratory of Control Technology and Standard for Agro-Product Safety and Quality (Nanjing), Ministry of Agriculture/Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
[Ti] Título:Involvement of threonine deaminase FgIlv1 in isoleucine biosynthesis and full virulence in Fusarium graminearum.
[So] Source:Curr Genet;61(1):55-65, 2015 Feb.
[Is] ISSN:1432-0983
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In this study we characterized FgIlv1, a homologue of the Saccharomyces cerevisiae threonine dehydratase (TD) from the important Fusarium head blight fungus Fusarium graminearum. TD catalyzes the first step in the biosynthesis pathway of isoleucine (Ile) for conversion of threonine (Thr) to 2-ketobutyrate (2-KB). The FgILV1 deletion mutant ΔFgIlv1-3 was unable to grow on minimal medium or fructose gelatin agar which lacked Ile. Exogenous supplementation of Ile or 2-KB but not Thr rescued the mycelial growth defect of ΔFgIlv1-3, indicating the involvement of FgIlv1 in the conversion of Thr to 2-KB in Ile biosynthesis. Additionally, exogenous supplementation of Methionine (Met) could also rescue the mycelial growth defect of ΔFgIlv1-3, indicating a crosstalk between Ile biosynthesis and Met catabolism in F. graminearum. Deletion of FgILV1 also caused defects in conidial formation and germination. In addition, ΔFgIlv1-3 displayed decreased virulence on wheat heads and a low level of deoxynivalenol (DON) production in wheat kernels. Taken together, results of this study indicate that FgIlv1 is an essential component in Ile biosynthesis and is required for various cellular processes including mycelial and conidial morphogenesis, DON biosynthesis, and full virulence in F. graminearum. Our data indicate the potential of targeting Ile biosynthesis for anti-FHB management.
[Mh] Termos MeSH primário: Fusarium/metabolismo
Fusarium/patogenicidade
Isoleucina/biossíntese
Treonina Desidratase/metabolismo
[Mh] Termos MeSH secundário: Aminoácidos/metabolismo
Cistationina gama-Liase/genética
Fusarium/genética
Deleção de Genes
Teste de Complementação Genética
Mutação
Micélio/genética
Micélio/crescimento & desenvolvimento
Fenótipo
Doenças das Plantas/microbiologia
Análise de Sequência de DNA
Esporos Fúngicos/genética
Treonina Desidratase/genética
Triticum/microbiologia
Virulência/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amino Acids); 04Y7590D77 (Isoleucine); EC 4.3.1.19 (Threonine Dehydratase); EC 4.4.1.1 (Cystathionine gamma-Lyase)
[Em] Mês de entrada:1509
[Cu] Atualização por classe:171004
[Lr] Data última revisão:
171004
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140818
[St] Status:MEDLINE
[do] DOI:10.1007/s00294-014-0444-z



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