Base de dados : MEDLINE
Pesquisa : B03.440.400.425.525.520.500 [Categoria DeCS]
Referências encontradas : 32 [refinar]
Mostrando: 1 .. 10   no formato [Longo]

página 1 de 4 ir para página            

  1 / 32 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
PMID:21698377
Autor:Akhverdyan VZ; Gak ER; Tokmakova IL; Stoynova NV; Yomantas YA; Mashko SV
Endereço:Ajinomoto-Genetika Research Institute, Moscow 117545, Russian Federation.
Título:Application of the bacteriophage Mu-driven system for the integration/amplification of target genes in the chromosomes of engineered Gram-negative bacteria--mini review.
Fonte:Appl Microbiol Biotechnol; 91(4):857-71, 2011 Aug.
ISSN:1432-0614
País de publicação:Germany
Idioma:eng
Resumo:The advantages of phage Mu transposition-based systems for the chromosomal editing of plasmid-less strains are reviewed. The cis and trans requirements for Mu phage-mediated transposition, which include the L/R ends of the Mu DNA, the transposition factors MuA and MuB, and the cis/trans functioning of the E element as an enhancer, are presented. Mini-Mu(LR)/(LER) units are Mu derivatives that lack most of the Mu genes but contain the L/R ends or a properly arranged E element in cis to the L/R ends. The dual-component system, which consists of an integrative plasmid with a mini-Mu and an easily eliminated helper plasmid encoding inducible transposition factors, is described in detail as a tool for the integration/amplification of recombinant DNAs. This chromosomal editing method is based on replicative transposition through the formation of a cointegrate that can be resolved in a recombination-dependent manner. (E-plus)- or (E-minus)-helpers that differ in the presence of the trans-acting E element are used to achieve the proper mini-Mu transposition intensity. The systems that have been developed for the construction of stably maintained mini-Mu multi-integrant strains of Escherichia coli and Methylophilus methylotrophus are described. A novel integration/amplification/fixation strategy is proposed for consecutive independent replicative transpositions of different mini-Mu(LER) units with "excisable" E elements in methylotrophic cells.
Tipo de publicação: JOURNAL ARTICLE; REVIEW


  2 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:21599015
Autor:Quintas PO; Catarino T; Todorovic S; Turner DL
Endereço:Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
Título:Highly selective ligand binding by Methylophilus methylotrophus cytochrome c''.
Fonte:Biochemistry; 50(25):5624-32, 2011 Jun 28.
ISSN:1520-4995
País de publicação:United States
Idioma:eng
Resumo:Cytochrome c'' (cyt c'') from Methylophilus methylotrophus is unusual insofar as the heme has two axial histidine ligands in the oxidized form but one is detached when the protein is reduced. Despite cyt c'' having an axial site available for binding small ligands, we show here that only NO binds readily to the ferrous cyt c''. Binding of CO, as well as CN(-), on the other hand requires considerable structural reorganization, or reduction of the disulfide bridge close to the heme. Standard free energies for the binding of NO and CO reveal high selectivity of the ferrous cyt c'' for NO, indicating its putative physiological role. In this work, we characterize in detail the kinetics of NO binding and the structural features of the Fe(2+)-NO adduct by stopped-flow and resonance Raman spectroscopy, respectively.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Bacterial Proteins); 0 (Disulfides); 0 (Ferrous Compounds); 0 (Ligands); 31C4KY9ESH (Nitric Oxide); 42VZT0U6YR (Heme); 4QD397987E (Histidine); 9007-43-6 (Cytochromes c)


  3 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
PMID:19880640
Autor:Yomantas YA; Tokmakova IL; Gorshkova NV; Abalakina EG; Kazakova SM; Gak ER; Mashko SV
Endereço:Ajinomoto-Genetika Research Institute, Moscow 117545, Russian Federation.
Título:Aromatic amino acid auxotrophs constructed by recombinant marker exchange in Methylophilus methylotrophus AS1 cells expressing the aroP-encoded transporter of Escherichia coli.
Fonte:Appl Environ Microbiol; 76(1):75-83, 2010 Jan.
ISSN:1098-5336
País de publicação:United States
Idioma:eng
Resumo:The isolation of auxotrophic mutants, which is a prerequisite for a substantial genetic analysis and metabolic engineering of obligate methylotrophs, remains a rather complicated task. We describe a novel method of constructing mutants of the bacterium Methylophilus methylotrophus AS1 that are auxotrophic for aromatic amino acids. The procedure begins with the Mu-driven integration of the Escherichia coli gene aroP, which encodes the common aromatic amino acid transporter, into the genome of M. methylotrophus. The resulting recombinant strain, with improved permeability to certain amino acids and their analogues, was used for mutagenesis. Mutagenesis was carried out by recombinant substitution of the target genes in the chromosome by linear DNA using the FLP-excisable marker flanked with cloned homologous arms longer than 1,000 bp. M. methylotrophus AS1 genes trpE, tyrA, pheA, and aroG were cloned in E. coli, sequenced, disrupted in vitro using a Kmr marker, and electroporated into an aroP carrier recipient strain. This approach led to the construction of a set of marker-less M. methylotrophus AS1 mutants auxotrophic for aromatic amino acids. Thus, introduction of foreign amino acid transporter genes appeared promising for the following isolation of desired auxotrophs on the basis of different methylotrophic bacteria.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Amino Acid Transport Systems); 0 (Amino Acids, Aromatic); 0 (AroP protein, E coli); 0 (DNA, Bacterial); 0 (Escherichia coli Proteins)


  4 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
PMID:18997032
Autor:Nakonieczna J; Kaczorowski T; Obarska-Kosinska A; Bujnicki JM
Endereço:Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk, and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland. strzala@biotech.ug.gda.pl
Título:Functional analysis of MmeI from methanol utilizer Methylophilus methylotrophus, a subtype IIC restriction-modification enzyme related to type I enzymes.
Fonte:Appl Environ Microbiol; 75(1):212-23, 2009 Jan.
ISSN:1098-5336
País de publicação:United States
Idioma:eng
Resumo:MmeI from Methylophilus methylotrophus belongs to the type II restriction-modification enzymes. It recognizes an asymmetric DNA sequence, 5'-TCCRAC-3' (R indicates G or A), and cuts both strands at fixed positions downstream of the specific site. This particular feature has been exploited in transcript profiling of complex genomes (using serial analysis of gene expression technology). We have shown previously that the endonucleolytic activity of MmeI is strongly dependent on the presence of S-adenosyl-l-methionine (J. Nakonieczna, J. W. Zmijewski, B. Banecki, and A. J. Podhajska, Mol. Biotechnol. 37:127-135, 2007), which puts MmeI in subtype IIG. The same cofactor is used by MmeI as a methyl group donor for modification of an adenine in the upper strand of the recognition site to N(6)-methyladenine. Both enzymatic activities reside in a single polypeptide (919 amino acids [aa]), which puts MmeI also in subtype IIC of the restriction-modification systems. Based on a molecular model, generated with the use of bioinformatic tools and validated by site-directed mutagenesis, we were able to localize three functional domains in the structure of the MmeI enzyme: (i) the N-terminal portion containing the endonucleolytic domain with the catalytic Mg2+-binding motif D(70)-X(9)-EXK(82), characteristic for the PD-(D/E)XK superfamily of nucleases; (ii) a central portion (aa 310 to 610) containing nine sequence motifs conserved among N(6)-adenine gamma-class DNA methyltransferases; (iii) the C-terminal portion (aa 610 to 919) containing a putative target recognition domain. Interestingly, all three domains showed highest similarity to the corresponding elements of type I enzymes rather than to classical type II enzymes. We have found that MmeI variants deficient in restriction activity (D70A, E80A, and K82A) can bind and methylate specific nucleotide sequence. This suggests that domains of MmeI responsible for DNA restriction and modification can act independently. Moreover, we have shown that a single amino acid residue substitution within the putative target recognition domain (S807A) resulted in a MmeI variant with a higher endonucleolytic activity than the wild-type enzyme.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:9007-49-2 (DNA); EC 3.1.21.- (endodeoxyribonuclease MmeI); EC 3.1.21.4 (Deoxyribonucleases, Type II Site-Specific)


  5 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:19134554
Autor:Ishikawa K; Toda-Murakoshi Y; Ohnishi F; Kondo K; Osumi T; Asano K
Endereço:Fermentation and Biotechnology Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan. kouhei_ishikawa@ajinomoto.com
Título:Medium composition suitable for L-lysine production by Methylophilus methylotrophus in fed-batch cultivation.
Fonte:J Biosci Bioeng; 106(6):574-9, 2008 Dec.
ISSN:1347-4421
País de publicação:Japan
Idioma:eng
Resumo:L-Lysine production was investigated in fed-batch fermentation using L-lysine producer of Methylophilus methylotrophus. By the addition of nutrient composition, containing L-methionine, K(2)HPO(4), NaH(2)PO(4), CuSO(4).5aq, MnSO(4).5aq, ZnSO(4).7aq, FeCl(3), MgSO(4).7aq and CaCl(2).2aq, in the feed medium, cell growth could be maintained through the cultivation, and L-lysine production reached to 7.86 g. In addition, the effect of counter ion for NH(4)(+) (Cl(-), SO(4)(2-), glutamate, succinate and citrate) was examined. The result showed that the cell growth in the medium using Cl(-) and glutamate were improved compared with that using SO(4)(2-), succinate and citrate, and L-lysine production in the medium using Cl(-) and glutamate reached to more than 9.0 g. In this experiment, there was a clear correlation between ionic strength and growth rate in the cultivation. In order to examine the influence of ionic strength on growth rate, the activity of enzymes in central metabolic pathway from methanol to pyruvate were assayed using samples at the log-phase and the stationary phase in fed-batch cultivation using (NH(4))(2)SO(4) and (NH(4))Cl as ammonium source. It was found that the higher ionic strength inhibited methanol oxidation activity, which linked to cell growth. In this report, it was revealed that maintaining a relatively low ionic strength had a positive effect on L-lysine production using L-lysine producer of M. methylotrophus.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Culture Media); 0 (Quaternary Ammonium Compounds); K3Z4F929H6 (Lysine)


  6 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PubMed Central Texto completo
Texto completo
PMID:18931376
Autor:Morgan RD; Bhatia TK; Lovasco L; Davis TB
Endereço:New England Biolabs Inc., Ipswich, MA and MCB Department, Brown University, Providence, RI, USA.
Título:MmeI: a minimal Type II restriction-modification system that only modifies one DNA strand for host protection.
Fonte:Nucleic Acids Res; 36(20):6558-70, 2008 Nov.
ISSN:1362-4962
País de publicação:England
Idioma:eng
Resumo:MmeI is an unusual Type II restriction enzyme that is useful for generating long sequence tags. We have cloned the MmeI restriction-modification (R-M) system and found it to consist of a single protein having both endonuclease and DNA methyltransferase activities. The protein comprises an amino-terminal endonuclease domain, a central DNA methyltransferase domain and C-terminal DNA recognition domain. The endonuclease cuts the two DNA strands at one site simultaneously, with enzyme bound at two sites interacting to accomplish scission. Cleavage occurs more rapidly than methyl transfer on unmodified DNA. MmeI modifies only the adenine in the top strand, 5'-TCCRAC-3'. MmeI endonuclease activity is blocked by this top strand adenine methylation and is unaffected by methylation of the adenine in the complementary strand, 5'-GTYGGA-3'. There is no additional DNA modification associated with the MmeI R-M system, as is required for previously characterized Type IIG R-M systems. The MmeI R-M system thus uses modification on only one of the two DNA strands for host protection. The MmeI architecture represents a minimal approach to assembling a restriction-modification system wherein a single DNA recognition domain targets both the endonuclease and DNA methyltransferase activities.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:EC 2.1.1.72 (Site-Specific DNA-Methyltransferase (Adenine-Specific)); EC 3.1.21.- (endodeoxyribonuclease MmeI); EC 3.1.21.4 (Deoxyribonucleases, Type II Site-Specific); JAC85A2161 (Adenine)


  7 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:18838820
Autor:Ishikawa K; Gunji Y; Yasueda H; Asano K
Endereço:Fermentation and Biotechnology Laboratories, Ajinomoto Co., Inc., Kawasaki, Japan. kouhei_ishikawa@ajinomoto.com
Título:Improvement of L-lysine production by Methylophilus methylotrophus from methanol via the Entner-Doudoroff pathway, originating in Escherichia coli.
Fonte:Biosci Biotechnol Biochem; 72(10):2535-42, 2008 Oct.
ISSN:1347-6947
País de publicação:England
Idioma:eng
Resumo:To improve the amino acid production by metabolic engineering, eliminating the pathway bottleneck is known to be very effective. The metabolic response of Methylophilus methylotrophus upon the addition of glucose and of pyruvate was investigated in batch cultivation. We found that the supply of pyruvate is a bottleneck in L-lysine production in M. methylotrophus from methanol as carbon source. M. methylotrophus has a ribulose monophosphate (RuMP) pathway for methanol assimilation, and consequently synthesized fructose-6-phosphate is metabolized to pyruvate via the Entner-Doudoroff (ED) pathway, and the ED pathway is thought to be the main pathway for pyruvate supply. An L-lysine producer of M. methylotrophus with an enhanced ED pathway was constructed by the introduction of the E. coli edd-eda operon encoding the enzyme involving the ED pathway. In this strain, the overall enzymatic activity of ED pathway, which is estimated by measuring the activities of 6-phosphogluconate dehydrogenase plus 2-keto-3-deoxy-6-phosphogluconate aldolase, was about 20 times higher than in the parent. This strain produced 1.2 times more L-lysine than the parent producer. Perhaps, then, the supply of pyruvate was a bottleneck in L-lysine production in the L-lysine producer of M. methylotrophus.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Pyruvates); IY9XDZ35W2 (Glucose); K3Z4F929H6 (Lysine); Y4S76JWI15 (Methanol)


  8 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:18820908
Autor:Abalakina EG; Tokmakova IL; Gorshkova NV; Gak ER; Akhverdyan VZ; Mashko SV; Yomantas YA
Endereço:Ajinomoto-Genetika Research Institute, 117545, Moscow, Russian Federation.
Título:Phage Mu-driven two-plasmid system for integration of recombinant DNA in the Methylophilus methylotrophus genome.
Fonte:Appl Microbiol Biotechnol; 81(1):191-200, 2008 Nov.
ISSN:1432-0614
País de publicação:Germany
Idioma:eng
Resumo:A phage Mu-driven two-plasmid system for DNA integration in Escherichia coli genome has been adjusted for Methylophilus methylotrophus. Constructed helper plasmids with broad-host-range replicons carry thermo-inducible genes for transposition factors MuA and MuB. Integrative plasmids that are only replicated in E. coli could be mobilized to M. methylotrophus and contained mini-Mu unit with a short terminus of Mu DNA, Mu-attL/R. Mini-Mu unit was integrated in the M. methylotrophus genome via mobilization of the integrative plasmid to the cells carrying the helper in conditions of thermo-induced expression of MuA and MuB. In this system, mini-Mu unit was mainly integrated due to replicative transposition, and the integrated copy could be amplified in the M. methylotrophus chromosome in the presence of helper plasmid. A kan-gene flanked by FRT sites was inserted in one of the mini-Mu units, and it could be readily excised by yeast FLP recombinase that is encoded by the designed plasmid. The multiple Mu-driven gene insertion was carried out by integration of the Bacillus amyloliquefaciens alpha-amylase gene followed by curing the KmR marker before integration of the second mini-Mu unit with Pseudomonas putida xylE gene encoding catechol 2,3-dioxygenase (C23O).
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (DNA Transposable Elements)


  9 / 32 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:18460806
Autor:Ishikawa K; Asahara T; Gunji Y; Yasueda H; Asano K
Endereço:Fermentation and Biotechnology Laboratories, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan. kouhei_ishikawa@ajinomoto.com
Título:Disruption of metF increased L-lysine production by Methylophilus methylotrophus from methanol.
Fonte:Biosci Biotechnol Biochem; 72(5):1317-24, 2008 May.
ISSN:1347-6947
País de publicação:England
Idioma:eng
Resumo:Methionine auxotrophic mutants of Methylophilus methylotrophus AS1 expressing a mutant form of dapA (dapA24) encoding a dihydrodipicolinate synthase desensitized from feedback inhibition by L-lysine, and mutated lysE (lysE24) encoding the L-lysine exporter from Corynebacterium glutamicum 2256, produced higher amounts of L-lysine from methanol as sole carbon source than did other amino acid auxotrophic mutants. Especially, the M. methylotrophus 102 strain, carrying both dapA24 and lysE24, produced L-lysine in more than 1.5 times amounts higher than the parent. A single-base substitution was identified in this auxotroph in codon-329 of the open reading frame of metF, encoding 5,10-methylene-tetra-hydrofolate reductase. We constructed a metF disruptant mutant carrying both dapA24 and lysE24, and confirmed increases in L-lysine production. This is the first report to the effect that metF deficient increased L-lysine production in methylotroph.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:AE28F7PNPL (Methionine); EC 1.5.1.20 (5,10-Methylenetetrahydrofolate Reductase (FADH2)); EC 2.7.1.- (Phosphotransferases (Alcohol Group Acceptor)); EC 2.7.1.39 (homoserine kinase); K3Z4F929H6 (Lysine); Y4S76JWI15 (Methanol)


  10 / 32 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:18407658
Autor:Burgess SG; Messiha HL; Katona G; Rigby SE; Leys D; Scrutton NS
Endereço:Department of Biochemistry, University of Leicester, Leicester LE1 9HN, UK.
Título:Probing the dynamic interface between trimethylamine dehydrogenase (TMADH) and electron transferring flavoprotein (ETF) in the TMADH-2ETF complex: role of the Arg-alpha237 (ETF) and Tyr-442 (TMADH) residue pair.
Fonte:Biochemistry; 47(18):5168-81, 2008 May 06.
ISSN:1520-4995
País de publicação:United States
Idioma:eng
Resumo:We have used multiple solution state techniques and crystallographic analysis to investigate the importance of a putative transient interaction formed between Arg-alpha237 in electron transferring flavoprotein (ETF) and Tyr-442 in trimethylamine dehydrogenase (TMADH) in complex assembly, electron transfer, and structural imprinting of ETF by TMADH. We have isolated four mutant forms of ETF altered in the identity of the residue at position 237 (alphaR237A, alphaR237K, alphaR237C, and alphaR237E) and with each form studied electron transfer from TMADH to ETF, investigated the reduction potentials of the bound ETF cofactor, and analyzed complex formation. We show that mutation of Arg-alpha237 substantially destabilizes the semiquinone couple of the bound FAD and impedes electron transfer from TMADH to ETF. Crystallographic structures of the mutant ETF proteins indicate that mutation does not perturb the overall structure of ETF, but leads to disruption of an electrostatic network at an ETF domain boundary that likely affects the dynamic properties of ETF in the crystal and in solution. We show that Arg-alpha237 is required for TMADH to structurally imprint the as-purified semiquinone form of wild-type ETF and that the ability of TMADH to facilitate this structural reorganization is lost following (i) redox cycling of ETF, or simple conversion to the oxidized form, and (ii) mutagenesis of Arg-alpha237. We discuss this result in light of recent apparent conflict in the literature relating to the structural imprinting of wild-type ETF. Our studies support a mechanism of electron transfer by conformational sampling as advanced from our previous analysis of the crystal structure of the TMADH-2ETF complex [Leys, D. , Basran, J. , Sutcliffe, M. J., and Scrutton, N. S. (2003) Nature Struct. Biol. 10, 219-225] and point to a key role for the Tyr-442 (TMADH) and Arg-alpha237 (ETF) residue pair in transiently stabilizing productive electron transfer configurations. Our work also points to the importance of Arg-alpha237 in controlling the thermodynamics of electron transfer, the dynamics of ETF, and the protection of reducing equivalents following disassembly of the TMADH-2ETF complex.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Electron-Transferring Flavoproteins); 42HK56048U (Tyrosine); 94ZLA3W45F (Arginine); EC 1.5.- (Oxidoreductases, N-Demethylating); EC 1.5.8.2 (trimethylamine dehydrogenase)



página 1 de 4 ir para página            
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde