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biochemical characterisation of aconitase from corynebacterium glutamicum.in this work, aconitase of the biotechnologically relevant microorganism corynebacterium glutamicum was characterised. the specific activity of aconitase in extracts of glucose-grown cells was determined by four different assays. in three of them the formation or disappearance of cis-aconitate was measured, whereas in the fourth assay the aconitase reaction was coupled with isocitrate dehydrogenase. the highest activity was determined with cis-aconitate as substrate (0.433+/-0.054umg(-1)) and th ...201020647021
quantitative proteomic overview on the corynebacterium glutamicuml-lysine producing strain dm1730.corynebacterium glutamicum is one of the most important microorganisms because of its ability to produce and secrete glutamate, lysine and other amino acids. to optimize biotechnological amino acid synthesis it is therefore necessary to understand well how metabolic fluxes can be altered by studying the proteins directing these fluxes. in this work we give a comprehensive quantitative outline about the proteomic state of the l-lysine producing mutant strain dm1730 compared to wild type strain at ...201020650338
tetrahydrolipstatin inhibition, functional analyses, and three-dimensional structure of a lipase essential for mycobacterial viability.the highly complex and unique mycobacterial cell wall is critical to the survival of mycobacteria in host cells. however, the biosynthetic pathways responsible for its synthesis are, in general, incompletely characterized. rv3802c from mycobacterium tuberculosis is a partially characterized phospholipase/thioesterase encoded within a genetic cluster dedicated to the synthesis of core structures of the mycobacterial cell wall, including mycolic acids and arabinogalactan. enzymatic assays performe ...201020656688
l-glutamine as a nitrogen source for corynebacterium glutamicum: derepression of the amtr regulon and implications for nitrogen sensing.corynebacterium glutamicum, a gram-positive soil bacterium employed in the industrial production of various amino acids, is able to use a number of different nitrogen sources, such as ammonium, urea or creatinine. this study shows that l-glutamine serves as an excellent nitrogen source for c. glutamicum and allows similar growth rates in glucose minimal medium to those in ammonium. a transcriptome comparison revealed that the nitrogen starvation response was elicited when glutamine served as the ...201020656783
corynebacterium glutamicum exhibits a membrane-related response to a small ferrocene-conjugated antimicrobial peptide.multiresistant bacteria are becoming more and more widespread. it is therefore necessary to have new compound groups in hand, such as small cationic peptides, to cope with these challenges. in this work, we present a comprehensive approach by monitoring protein expression profiles in a gram-positive bacterium (corynebacterium glutamicum) to investigate the cellular response to such a compound, a ferrocene-conjugated arginine- and tryptophan-rich pentapeptide. to achieve this, a proteomic outline ...201020658302
putrescine production by engineered corynebacterium glutamicum.here, we report the engineering of the industrially relevant corynebacterium glutamicum for putrescine production. c. glutamicum grew well in the presence of up to 500 mm of putrescine. a reduction of the growth rate by 34% and of biomass formation by 39% was observed at 750 mm of putrescine. c. glutamicum was enabled to produce putrescine by heterologous expression of genes encoding enzymes of the arginine- and ornithine decarboxylase pathways from escherichia coli. the results showed that the ...201020661733
the e2 domain of odha of corynebacterium glutamicum has succinyltransferase activity dependent on lipoyl residues of the acetyltransferase acef.oxoglutarate dehydrogenase (odh) and pyruvate dehydrogenase (pdh) complexes catalyze key reactions in central metabolism, and in corynebacterium glutamicum there is indication of an unusual supercomplex consisting of acee (e1), acef (e2), and lpd (e3) together with odha. odha is a fusion protein of additional e1 and e2 domains, and odha orthologs are present in all corynebacterineae, including, for instance, mycobacterium tuberculosis. here we show that deletion of any of the individual domains ...201020675489
combined dissolved oxygen and ph control strategy to improve the fermentative production of l-isoleucine by brevibacterium lactofermentum.the effect of both dissolved oxygen (do) and ph on l: -isoleucine production by batch culture of brevibacterium lactofermentum was investigated. a two-stage agitation speed control strategy was developed, and the isoleucine production reached 23.3 g l(-1) in a relative short time (52 h), increased by 11.6% compared to the results obtained in the single agitation speed control process. in order to make sure whether the combination of do and ph control can boost the production by a mutual effect, ...201019449037
optical device for parallel online measurement of dissolved oxygen and ph in shake flask cultures.we describe a new device with parallel optical measurement of dissolved oxygen (do) and ph in up to nine shake flasks applicable in any conventional shaking incubator. measurement ranges are 0-500% of air saturation for oxygen and 5.5-8.5 for ph. it was used to characterize growth profiles of different l-lysine producing strains of corynebacterium glutamicum, of saccharomyces cerevisiae and of escherichia coli. cultures in unbaffled flasks were highly reproducible. oxygen limitation was indicate ...201019701780
conversion of phenol to glutamate and proline in corynebacterium glutamicum is regulated by transcriptional regulator argr.this paper reports a novel integrated metabolic pathway of amino acid production through the utilization of phenol in corynebacterium glutamicum. in the presence of 8.5 mm phenol, the level of glutamate and proline production increased up to 1.2- and 14.7-fold, respectively, compared to the control condition. in addition, their productivities increased 1.6- and 20-fold in the culture medium using phenol as the sole carbon source with 72 microm feso(4) as iron supplementation. chromatin immunopre ...201019707750
characterization of an adenylate cyclase gene (cyab) deletion mutant of corynebacterium glutamicum atcc 13032.genome analysis of c. glutamicum atcc 13032 has showed one putative adenylate cyclase gene, cyab (cg0375) which encodes membrane protein belonging to class iii adenylate cyclases. to characterize the function of cyab, a deletion mutant was constructed, and the mutant showed decreased level of intracellular cyclic amp compared to that of wild-type. interestingly, the cyab mutant displayed growth defect on acetate medium, and this effect was reversed by complementation with cyab gene. similarly, i ...201019568747
proline reduces the binding of transcriptional regulator argr to upstream of argb in corynebacterium glutamicum.in this study, the argr-binding sites on the arg operon corynbebacterium glutamicum were characterized by in vivo chromatin immunoprecipitation (chip). in addition, the argr-binding affinity in the presence of glutamate, proline, or arginine was examined to get further information on expression control. the chip assay showed that the argr protein binds specifically to the upstream regions of argc, argb, argf, and argg. upon proline supplementation, argr-binding affinity was significantly reduced ...201019798496
biotechnological production of enantiomeric pure lactic acid from renewable resources: recent achievements, perspectives, and limits.lactic acid (la) is an important and versatile chemical that can be produced from renewable resources such as biomass. la is used in the food, pharmaceutical, and polymers industries and is produced by microorganism fermentation; however, most microorganisms cannot directly utilize biomass such as starchy materials and cellulose. here, we summarize la production using several kinds of genetically modified microorganisms, such as la bacteria, escherichia coli, corynebacterium glutamicum, and yeas ...201019826806
sugar transporters in efficient utilization of mixed sugar substrates: current knowledge and outlook.there is increasing interest in production of transportation fuels and commodity chemicals from lignocellulosic biomass, most desirably through biological fermentation. considerable effort has been expended to develop efficient biocatalysts that convert sugars derived from lignocellulose directly to value-added products. glucose, the building block of cellulose, is the most suitable fermentation substrate for industrial microorganisms such as escherichia coli, corynebacterium glutamicum, and sac ...201019838697
increased glucose utilization in corynebacterium glutamicum by use of maltose, and its application for the improvement of l-valine productivity.corynebacterium glutamicum efficiently utilizes maltose as a substrate. we show here that the presence of maltose increases glucose utilization by raising the expression of ptsg, which encodes the glucose-specific eii permease of the phosphotransferase system. consequently, the l-valine productivity of a pyruvate dehydrogenase complex-deficient c. glutamicum strain was improved by the presence of maltose.201019880641
antimycobacterial activities of selected medicinal plants from zimbabwe against mycobacterium aurum and corynebacterium glutamicum.the spread of multi-drug resistant tuberculosis necessitates the discovery of new classes of antibacterials and compounds that inhibit macromolecules involved in these resistant mechanisms. thirty ethanol extracts from nineteen selected plants from zimbabwe were screened against mycobacterium aurum and corynebacterium glutamicum using the agar disk diffusion method. these two organisms were used as models for mycobacterium tuberculosis. the amount of ciprofloxacin accumulated and effluxed by the ...201021399602
identification and characterization of a transcriptional regulator, sucr, that influences succd transcription in corynebacterium glutamicum.we have identified and characterized a novel transcriptional regulator that binds to the promoter region of succinyl-coa synthetase (succd) in corynebacterium glutamicum. using biotin-labeled dna affinity beads, we identified a deor-type transcriptional regulator, sucr (cg0146), which is a protein consisting of 282 amino acids with a mass of 31 kda and ramb (cg0444). the results of electrophoretic mobility shift assays verified that these regulators specifically bind to the succd promoter region ...201020851105
engineering of corynebacterium glutamicum with an nadph-generating glycolytic pathway for l-lysine production.a sufficient supply of nadph is a critical factor in l-lysine production by corynebacterium glutamicum. endogenous nad-dependent glyceraldehyde 3-phosphate dehydrogenase (gapdh) of c. glutamicum was replaced with nonphosphorylating nadp-dependent glyceraldehyde 3-phosphate dehydrogenase (gapn) of streptococcus mutans, which catalyzes the reaction of glyceraldehyde 3-phosphate to 3-phosphoglycerate with the reduction of nadp(+) to nadph, resulting in the reconstruction of the functional glycolyti ...201020851994
adaptation of amtr-controlled gene expression by modulation of amtr binding activity in corynebacterium glutamicum.in corynebacteria, nitrogen regulation is controlled by the tetr family protein amtr, which was extensively studied in the last years. in frame of these studies a number of amtr binding sites were identified and characterized and it became obvious that for distinct genes the number and sequences of these sites varied significantly. in this study, the influence of numbers and alterations of amtr binding sites were addressed by in vivo and in vitro studies. it can be concluded that in general a si ...201020854853
regulation of the nitrate reductase operon narkghji by the camp-dependent regulator glxr in corynebacterium glutamicum.the corynebacterium glutamicum anaerobic nitrate reductase operon narkghji is repressed by a transcriptional regulator, arnr, under aerobic conditions. a consensus binding site of the camp receptor protein (crp)-type regulator, glxr, was recently found upstream of the arnr binding site in the nark promoter region. here we investigated the involvement of glxr and camp in expression of the narkghji operon in vivo. electrophoretic mobility shift assays showed that the putative glxr binding motif in ...201020864477
engineering of nitrogen metabolism and its regulation in corynebacterium glutamicum: influence on amino acid pools and production.nitrogen is one of the macronutrients necessary for living cells, and consequently, assimilation of nitrogen is a crucial step for metabolism. to satisfy their nitrogen demand and to ensure a sufficient nitrogen supply even in situations of nitrogen limitation, microorganisms have evolved sophisticated uptake and assimilation mechanisms for different nitrogen sources. this mini-review focuses on nitrogen metabolism and its control in the biotechnology workhorse corynebacterium glutamicum, which ...201020922371
identification and quantification of mycothiol in actinobacteria by a novel enzymatic method.mycothiol (msh) was reported to be the dominant low molecular weight thiol in members of the actinobacteria. in this study, a simple, fast, and sensitive method for qualitative and quantitative determination of msh molecules was developed based on maleylpyruvate isomerase (mpi) from corynebacterium glutamicum. the principle of this method is that the activity of mpi from c. glutamicum was dependent on msh molecules. it was found that this mpi activity displayed a linear response (r (2) = 0.9928) ...201020922372
the bcct family of carriers: from physiology to crystal structure.increases in the environmental osmolarity are key determinants for the growth of microorganisms. to ensure a physiologically acceptable level of cellular hydration and turgor at high osmolarity, many bacteria accumulate compatible solutes. osmotically controlled uptake systems allow the scavenging of these compounds from scarce environmental sources as effective osmoprotectants. a number of these systems belong to the bcct family (betaine-choline-carnitine-transporter), sodium- or proton-coupled ...201020923416
the tetr-type transcriptional regulator fasr of corynebacterium glutamicum controls genes of lipid synthesis during growth on acetate.the addition of fatty acids to either escherichia coli or bacillus subtilis elicits an elaborate cellular response of the lipid metabolism. we found that in corynebacterium glutamicum the expression of accd1 encoding the β-subunit of the essential acetyl-coa carboxylase is repressed in acetate-grown cells without the addition of fatty acids. the tetr-type transcriptional regulator ncgl2404, termed fasr, was identified and deleted. during growth on acetate, but not on glucose, 17 genes are differ ...201020923423
leads for antitubercular compounds from kinase inhibitor library screens.discovering new drugs to treat tuberculosis more efficiently and to overcome multidrug resistance is a world health priority. to find antimycobacterial scaffolds, we screened a kinase inhibitor library of more than 12,000 compounds using an integrated strategy involving whole cell-based assays with corynebacterium glutamicum and mycobacterium tuberculosis, and a target-based assay with the protein kinase pkna. seventeen "hits" came from the whole cell-based screening approach, from which three d ...201020934382
metabolic engineering of corynebacterium glutamicum for 2-ketoisovalerate production.2-ketoisovalerate is used as a therapeutic agent, and a 2-ketoisovalerate-producing organism may serve as a platform for products deriving from this 2-keto acid. we engineered the wild type of corynebacterium glutamicum for the growth-decoupled production of 2-ketoisovalerate from glucose by deletion of the acee gene encoding the e1p subunit of the pyruvate dehydrogenase complex, deletion of the transaminase b gene ilve, and additional overexpression of the ilvbncd genes, encoding the l-valine b ...201020935122
the small ribosomal protein s12p gene rpsl as an efficient positive selection marker in allelic exchange mutation systems for corynebacterium glutamicum.we report that the mutant rpsl k43r in streptomycin-resistant and lysine-producing corynebacterium glutamicum is responsible for streptomycin resistance. in addition, we describe its effective application in gene modification in c. glutamicum.201020951172
preparation of pei-coated bacterial biosorbent in water solution: optimization of manufacturing conditions using response surface methodology.the aim of this study is to optimize preparation method of polyethyleneimine (pei)-coated bacterial biosorbent in water as reaction media using fermentation waste biomass of corynebacterium glutamicum as a raw material. the fermentation waste biomass of c. glutamicum and reactive red 4 were used as model raw bacterium and pollutant. major factors affecting the performance of pei-coated biosorbent were the amounts of polymer (pei) and cross-linker glutaraldehyde (ga). these factors were optimized ...201020961751
determination of co₂ sensitivity of micro-organisms in shaken bioreactors. i. novel method based on the resistance of sterile closure.influence of carbon dioxide on growth and product kinetics of industrially important micro-organisms is essential for the interpretation of a bioprocess. in this research, the co₂ effects on productivity and growth rate of micro-organisms have been studied by using a variety of kplug. the applied method is based on a different concentration of co₂ in the headspace of ventilation flasks. the presented method is simple, inexpensive and shows similar results compared to large-scale fermentation reg ...201020973762
regulation of genes involved in sugar uptake, glycolysis and lactate production in corynebacterium glutamicum.corynebacterium glutamicum is a nonpathogenic, gc-rich, gram-positive bacterium with a long history in the industrial production of amino acids. recently, the species has become of increasing interest as a model bacterium for closely related, medically important pathogenic species such as corynebacterium diphtheriae and mycobacterium tuberculosis. in this article, recent advances in understanding of the c. glutamicum regulatory network of genes involved in carbohydrate metabolism are reviewed wi ...201021073308
translation efficiency of antiterminator proteins is a determinant for the difference in glucose repression of two β-glucoside phosphotransferase system gene clusters in corynebacterium glutamicum r.corynebacterium glutamicum r has two β-glucoside phosphoenolpyruvate, carbohydrate phosphotransferase systems (pts) encoded by bglf and bglf2 located in the respective clusters, bglf-bgla-bglg and bglf2-bgla2-bglg2. previously, we reported that whereas β-glucoside-dependent induction of bglf is strongly repressed by glucose, glucose repression of bglf2 is very weak. here, we reveal the mechanism behind the different effects of glucose on the two bgl genes. deletion of the ribonucleic antitermina ...201021075922
mycolic acid-containing bacteria induce natural-product biosynthesis in streptomyces species.natural products produced by microorganisms are important starting compounds for drug discovery. secondary metabolites, including antibiotics, have been isolated from different streptomyces species. the production of these metabolites depends on the culture conditions. therefore, the development of a new culture method can facilitate the discovery of new natural products. here, we show that mycolic acid-containing bacteria can influence the biosynthesis of cryptic natural products in streptomyce ...201021097597
interaction of transcriptional repressor argr with transcriptional regulator farr at the argb promoter region in corynebacterium glutamicum.in corynebacterium glutamicum, the argr protein, a transcriptional repressor, affects the expression level of the argb gene through binding to its promoter region. the argb promoter region (positions -77 to -25) has been found by in vitro electrophoretic mobility shift assay (emsa) results and in silico analysis to be important for the dna binding of argr. proline supplementation prevented the dna binding of argr to the argb promoter region and triggered an increase of the argb mrna level. addit ...201021115700
identification of mannose uptake and catabolism genes in corynebacterium glutamicum and genetic engineering for simultaneous utilization of mannose and glucose.here, focus is on corynebacterium glutamicum mannose metabolic genes with the aim to improve this industrially important microorganism's ability to ferment mannose present in mixed sugar substrates. cgr_0857 encodes c. glutamicum's protein with 36% amino acid sequence identity to mannose 6-phosphate isomerase encoded by mana of escherichia coli. its deletion mutant did not grow on mannose and exhibited noticeably reduced growth on glucose as sole carbon sources. in effect, c. glutamicum mana is ...201021125267
phenotypic characterization of corynebacterium glutamicum under osmotic stress conditions using elementary mode analysis.corynebacterium glutamicum, a soil bacterium, is used to produce amino acids such as lysine and glutamate. c. glutamicum is often exposed to osmolality changes in its medium, and the bacterium has therefore evolved several adaptive response mechanisms to overcome them. in this study we quantify the metabolic response of c. glutamicum under osmotic stress using elementary mode analysis (ema). further, we obtain the optimal phenotypic space for the synthesis of lysine and formation of biomass. the ...201021132515
the protein encoded by ncgl1221 in corynebacterium glutamicum functions as a mechanosensitive channel.the function of the ncgl1221-encoded protein of corynebacterium glutamicum was analyzed using bacillus subtilis as host because a method for preparing the giant provacuole required for electrophysiological studies has been established. expression of ncgl1221 in a strain deficient in mscl and ykut, both of which encode mechanosensitive channels, resulted in an 8.9-fold higher cell survival rate upon osmotic downshock than the control. electrophysiological investigation showed that the giant prova ...201021150093
quinone-dependent d-lactate dehydrogenase dld (cg1027) is essential for growth of corynebacterium glutamicum on d-lactate.corynebacterium glutamicum is able to grow with lactate as sole or combined carbon and energy source. quinone-dependent l-lactate dehydrogenase lldd is known to be essential for utilization of l-lactate by c. glutamicum. d-lactate also serves as sole carbon source for c. glutamicum atcc 13032.201021159175
escherichia coli exports cyclic amp via tolc.in escherichia coli more than 180 genes are regulated by the cyclic amp (camp)-camp receptor protein (crp) complex. however, more than 90% of camp that is made by intracellular adenylyl cyclases is found in the culture medium. how is camp exported from e. coli? in a tolc mutant, 0.03 mm iptg (isopropyl-β-d-thiogalactopyranoside) was sufficient to induce β-galactosidase compared to 0.1 mm iptg in the parent strain. in a cya mutant unable to produce camp about 1 mm extracellular camp was required ...201021183666
target genes, consensus binding site, and role of phosphorylation for the response regulator mtra of corynebacterium glutamicum.the two-component signal transduction system consisting of the sensor kinase mtrb and the response regulator mtra is highly conserved in corynebacteria and mycobacteria. whereas mtra of mycobacterium tuberculosis was reported to be essential, we recently succeeded in creating δmtrab and δmtra deletion mutants of corynebacterium glutamicum and provided evidence that mepa and nlpc, both encoding putative cell wall peptidases, are directly repressed by mtra, whereas prop and betp, both encoding car ...201021183673
utilization of pei-modified corynebacterium glutamicum biomass for the recovery of pd(ii) in hydrochloric solution.a new type of biosorbent was developed for binding anionic precious metals through cross-linking waste biomass corynebacterium glutamicum with polyethylenimine (pei). this biomass was evaluated for the removal and recovery of palladium and compared to commercial adsorbents, such as amberjet 4200 cl, lewatit monoplus tp 214, spc-100, and sps-200. the kinetic experiments revealed that the sorption equilibrium was reached with 30 min for the pei-modified biomass. the maximum uptake of the biosorben ...201021185173
detection of d-ornithine extracellularly produced by corynebacterium glutamicum atcc 13032::argf.we found that corynebacterium glutamicum atcc 13032::argf extracellularly produced a large amount of d-ornithine when cultivated in a cgxii medium containing 1 mm l-arginine. this is the first report that c. glutamicum atcc 13032 or its mutant produces a d-amino acid extracellularly. c. glutamicum atcc 13032::argf produced 13 mm d-ornithine in 45 h of cultivation.201021187642
enhancement of riboflavin production with bacillus subtilis by expression and site-directed mutagenesis of zwf and gnd gene from corynebacterium glutamicum.zwf (code for glucose-6-phosphate dehydrogenase) and gnd (code for 6-phosphogluconate dehydrogenase) genes from corynebacterium glutamicum were firstly cloned, and then site-directed mutagenesis was successfully introduced to remove allosteric inhibition by intracellular metabolites. expression of the mutant zwf and gnd in bacillus subtilis rh33 resulted in significant enhancement of riboflavin productivity, while the specific growth rate decreased slightly and the specific glucose uptake rate w ...201021194928
acceptor substrate discrimination in phosphatidyl-myo-inositol mannoside synthesis: structural and mutational analysis of mannosyltransferase corynebacterium glutamicum pimb'.long term survival of the pathogen mycobacterium tuberculosis in humans is linked to the immunomodulatory potential of its complex cell wall glycolipids, which include the phosphatidylinositol mannoside (pim) series as well as the related lipomannan and lipoarabinomannan glycoconjugates. pim biosynthesis is initiated by a set of cytosolic α-mannosyltransferases, catalyzing glycosyl transfer from the activated saccharide donor gdp-α-d-mannopyranose to the acceptor phosphatidyl-myo-inositol (pi) i ...201020843801
[metabolic flux analysis of l-serine synthesis by corynebacterium glutamicum syps-062].corynebacterium glutamicum syps-062 was an l-serine producing strain stored at our lab and could produce l-serine directly from sugar. we studied the effects of cofactors in one carbon unit metabolism-folate and vb12 on the cell growth, sucrose consumption and l-serine production by syps-062. in the same time, the metabolic flux distribution was determined in different conditions. the supplementation of folate or vb12 enhanced the cell growth, energy synthesis, and finally increased the flux of ...201021218623
[corynebacterium pekinense transketolase: gene cloning, sequence analysis and expression].transketolase (ec 2. 2. 1. 1; tk) is the key enzyme in non-oxidative phosphate pentose pathway. we cloned tkt gene from corynebacterium pekinense as 1.299 and its mutant pd-67 in order to investigate the effect of gene expression on physiological characteristics of c. pekinense. pd-67.201021268892
microbial renewable feedstock utilization: a substrate-oriented approach.increasingly lignocellulosic biomass hydrolysates are used as the feedstock for industrial fermentations. these biomass hydrolysates consist of complex mixtures of different fermentable sugars, but also contain inhibitors and salts that affect the performance of the product-generating microbes. the performance of six industrially relevant microorganisms, i.e., two bacteria (escherichia coli and corynebacterium glutamicum), two yeasts (saccharomyces cerevisiae and pichia stipitis) and two fungi ( ...201021326838
improved production of l-lysine by over-expression of meso-diaminopimelate decarboxylase enzyme of corynebacterium glutamicum in escherichia coli.the aim of this study is over-expression of meso-diaminopimelate decarboxylase enzyme (ec 4.1.1.20) and enhancement of l-lysine production rate. the c. glutamicum lysa gene which encodes a meso-diaminopimelate decarboxylase was cloned in e. coli. the cloned gene was sequenced; it encodes a 445 amino acids protein with molecular weight of 47 kd. expression of the lysa gene in e. coli resulted in an increase in meso-diaminopimelate decarboxylase activity, correlated with the presence in sodium dod ...201021848075
the effect of amtr on growth and amino acids production in corynebacterium glutamicum.amtr, the master regulator of nitrogen control in corynebacterium glutamicum, plays important roles in nitrogen metabolism. to investigate the influence of amtr on amino acids production in c. glutamicum atcc 13032, the amtr deletion strain c. glutamicum q1 was constructed and cultured in modified cgxii minimal medium for 60 h. the ammonium consumption rates as well as amino acids production of both strains cultured in modified cgxii minimal medium were determined. the amtr deletion in c. glutam ...201021254728
corynebacterium glutamicum as a host for synthesis and export of d-amino acids.a number of d-amino acids occur in nature, and there is growing interest in their function and metabolism, as well as in their production and use. here we use the well-established l-amino-acid-producing bacterium corynebacterium glutamicum to study whether d-amino acid synthesis is possible and whether mechanisms for the export of these amino acids exist. in contrast to escherichia coli, c. glutamicum tolerates d-amino acids added extracellularly. expression of argr (encoding the broad-substrate ...201121257776
molecular characterization of prpr, the transcriptional activator of propionate catabolism in corynebacterium glutamicum.the 2-methylcitrate cycle is used to metabolize propionate in corynebacterium glutamicum. the regulator, prpr (cg0800), of the prpdbc2 operon was identified and characterized. the regulator has no similarities to the up to now known prpr regulators from other organisms. growth of a δprpr mutant revealed severe growth deficits and a prolonged lag phase if propionate was present in the medium. transcriptome analyses demonstrated the inability of the δprpr strain to induce the prpdbc2 genes in the ...201121933687
The glgB-encoded glycogen branching enzyme is essential for glycogen accumulation in Corynebacterium glutamicum.Corynebacterium glutamicum transiently accumulates glycogen as carbon capacitor during the early exponential growth phase in media containing carbohydrates. In some bacteria glycogen is synthesized by the consecutive action of ADP-glucose pyrophosphorylase (GlgC), glycogen synthase (GlgA) and glycogen branching enzyme (GlgB). GlgC and GlgA of C. glutamicum have been shown to be necessary for glycogen accumulation in this organism. However, although cg1381 has been annotated as the putative C. gl ...201121903753
Site-Directed Mutagenesis Studies on the L: -Arginine-Binding Sites of Feedback Inhibition in N-Acetyl-L: -glutamate Kinase (NAGK) from Corynebacterium glutamicum.Arginine biosynthesis in Corynebacterium glutamicum proceeds via a pathway that is controlled by arginine through feedback inhibition of NAGK, the enzyme that converts N-acetyl-L: -glutamate (NAG) to N-acety-L: -glutamy-L: -phosphate. In this study, the gene argB encoding NAGK from C. glutamicum ATCC 13032 was site-directed, and the L: -arginine-binding sites of feedback inhibition in Cglu_NAGK are described. The N-helix and C-terminal residues were first deleted, and the results indicated that ...201122101454
Biotin protein ligase from Corynebacterium glutamicum: role for growth and L: -lysine production.Corynebacterium glutamicum is a biotin auxotrophic Gram-positive bacterium that is used for large-scale production of amino acids, especially of L: -glutamate and L: -lysine. It is known that biotin limitation triggers L: -glutamate production and that L: -lysine production can be increased by enhancing the activity of pyruvate carboxylase, one of two biotin-dependent proteins of C. glutamicum. The gene cg0814 (accession number YP_225000) has been annotated to code for putative biotin protein li ...201122159614
structural view of the regulatory subunit of aspartate kinase from mycobacterium tuberculosis.the aspartate kinase (ak) from mycobacterium tuberculosis (mtb) catalyzes the biosynthesis of aspartate family amino acids, including lysine, threonine, isoleucine and methionine. we determined the crystal structures of the regulatory subunit of aspartate kinase from mtb alone (referred to as mtbakβ) and in complex with threonine (referred to as mtbakβ-thr) at resolutions of 2.6 å and 2.0 å, respectively. mtbakβ is composed of two perpendicular non-equivalent act domains [aspartate kinase, chori ...201121976064
arabitol metabolism of corynebacterium glutamicum and its regulation by atlr.expression profiling of corynebacterium glutamicum in comparison to a derivative deficient of the transcriptional regulator atlr (previously known as sugr or mtlr) revealed eight genes showing more than fourfold higher mrna levels in the mutant. four of these are located in direct vicinity of the atlr gene, i.e., xylb, rbtt, mtld, and sixa, annotated as encoding xylulokinase, ribitol transporter, mannitol 2-dehydrogenase, and phosphohistidine phosphatase, respectively. transcriptional analysis i ...201122178972
bio-based production of chemicals, materials and fuels -corynebacterium glutamicum as versatile cell factory.since their discovery almost 60 years ago, corynebacterium glutamicum and related subspecies are writing a remarkable success story in industrial biotechnology. today, these gram-positive soil bacteria, traditionally well-known as excellent producers of l-amino acids are becoming flexible, efficient production platforms for various chemicals, materials and fuels. this development is intensively driven by systems metabolic engineering concepts integrating systems biology and synthetic biology int ...201122138494
Heterologous and homologous expression of the arginine biosynthetic argC~H cluster from Corynebacterium crenatum for improvement of L: -arginine production.The genes involved in L: -arginine biosynthesis in Corynebacterium crenatum are organized as the argCJBDFRGH cluster like in Corynebacterium glutamicum. However, the argC~H cluster of the C. crenatum SYPA 5-5, which is an industrialized L: -arginine producer, had a lethal mutation occurring in the ArgR repressor encoding gene. The argC~H cluster with an inactive argR was overexpressed in E. coli and C. crenatum. In the recombinant E. coli JM109 enzyme activities were increased, and more L: -argi ...201122009057
Impact of a new glucose utilization pathway in amino acid-producing Corynebacterium glutamicum.Corynebacterium glutamicum imports and phosphorylates glucose, fructose and sucrose by the phosphoenolpyruvate-dependent phosphotransferase carbohydrate uptake system (PTS). Recently, we have discovered how glucose can be utilized by C. glutamicum in a PTS-independent manner. PTS-independent glucose uptake is mediated by one of two inositol permeases (IolT1 or IolT2) and the second function of PTS, substrate phosphorylation, is catalyzed by one of two glucokinases (Glk or PpgK). PTS-deficient C. ...201122008639
conformational changes of the betaine transporter betp from corynebacterium glutamicum studied by pulse epr spectroscopy.the betaine transporter betp from corynebacterium glutamicum is activated by hyperosmotic stress critically depending on the presence and integrity of its sensory c-terminal domain. the conformational properties of the trimeric betp reconstituted in liposomes in the inactive state and during osmotic activation were investigated by site-directed spin labeling and electron paramagnetic resonance (epr) spectroscopy. comparison of intra- and intermolecular inter spin distance distributions obtained ...201122051018
diversity of metabolic shift in response to oxygen deprivation in corynebacterium glutamicum and its close relatives.oxygen-deprived corynebacterium glutamicum r cells remain metabolically active, producing considerable amounts of organic acids even when not actively growing. we compared the proficiencies of c. glutamicum and close relatives grown under aerobic conditions to metabolize glucose when deprived of oxygen. eight strains that readily consumed glucose without cell growth subsequently produced organic acids. among these, the glucose consumption rates of the two c. glutamicum strains (>40 mm/h) and cor ...201121327408
exploring the conformational dynamics and membrane interactions of porb from c. glutamicum: a multi-scale molecular dynamics simulation study.members of the gram-positive mycolata bacteria have unusual cell envelopes which help them to avoid the immune system and the effects of most antibiotics, whilst rendering them permeable to solutes of importance in industrial bioconversion. it is therefore of interest to understand the molecular mechanisms for this selective permeability. porb is an unusual porin from the outer membrane (om) of corynebacterium glutamicum. it has been proposed as an atypical a-helical, symmetrical homo-pentameric ...201121354102
efficient markerless gene replacement in corynebacterium glutamicum using a new temperature-sensitive plasmid.random chemical mutation of a corynebacterium glutamicum-escherichia coli shuttle vector derived from plasmid pcgr2 was done using hydroxylamine. it brought about amino acid substitutions g109d and e180k within the replicase superfamily domain of the plasmid's repa protein and rendered the plasmid highly unstable, especially at higher incubation temperatures. colony formation of c. glutamicum was consequently completely inhibited at 37°c but not at 25°c. g109 is a semi-conserved residue mutation ...201121362445
mixed glucose and lactate uptake by corynebacterium glutamicum through metabolic engineering.the corynebacterium glutamicum atcc 13032 lysc(fbr) strain was engineered to grow fast on racemic mixtures of lactate and to secrete lysine during growth on lactate as well as on mixtures of lactate and glucose. the wild-type c. glutamicum only grows well on l-lactate. overexpression of d-lactate dehydrogenase (dld) achieved by exchanging the native promoter of the dld gene for the stronger promoter of the sod gene encoding superoxide dismutase in c. glutamicum resulted in a duplication of bioma ...201121370474
quantitative lipid composition of cell envelopes of corynebacterium glutamicum elucidated through reverse micelle extraction.cells of the corynebacterium-nocardia-mycobacterium group of bacteria are surrounded by an outer membrane (om) containing mycolic acids that are covalently linked to the underlying arabinogalactan-peptidoglycan complex. this om presumably acts as a permeability barrier that imparts high levels of intrinsic drug resistance to some members of this group, such as mycobacterium tuberculosis, and its component lipids have been studied intensively in a qualitative manner over the years. however, the q ...201121876124
biochemical disclosure of the mycolate outer membrane of corynebacterium glutamicum.corynebacterineae is a specific sub-order of gram-positive bacteria that includes mycobacterium tuberculosis and corynebacterium glutamicum. their cell wall is composed of a heteropolymer of peptidoglycan (pg) linked to arabinogalactan (ag), which in turn, is covalently associated to an atypical outer membrane hereafter called mycomembrane (m). this latter structure has been visualized by cryoelectron microscopy of vitreous sections but its biochemical composition is still poorly defined, thereb ...201122123248
corynebacterium glutamicum as a potent biocatalyst for the bioconversion of pentose sugars to value-added products.corynebacterium glutamicum, the industrial microbe traditionally used for the production of amino acids, proved its value for the fermentative production of diverse products through genetic/metabolic engineering. a successful demonstration of the heterologous expression of arabinose and xylose utilization genes made them interesting biocatalysts for pentose fermentation, which are the main components in lignocellulosic hydrolysates. its ability to withstand substantial amount of general growth i ...201122094976
production of minicellulosomes for the enhanced hydrolysis of cellulosic substrates by recombinant corynebacterium glutamicum.although cellulosic materials of plant origin are the most abundant utilizable biomass resource, the amino acid-producing organism corynebacterium glutamicum can not utilize these materials. here we report the engineering of a c. glutamicum strain expressing functional minicellulosomes containing chimeric endoglucanase e bound to minicbpa from clostridium cellulovorans that can hydrolyze cellulosic materials. the chimeric endoglucanase e consists of the endoglucanase e catalytic backbone of clos ...201122112952
growth independent rhamnolipid production from glucose using the non-pathogenic pseudomonas putida kt2440.abstract:201121999513
Solution NMR structures reveal a distinct architecture and provide first structures for protein domain family PF04536.The protein family (Pfam) PF04536 is a broadly conserved domain family of unknown function (DUF477), with more than 1,350 members in prokaryotic and eukaryotic proteins. High-quality NMR structures of the N-terminal domain comprising residues 41-180 of the 684-residue protein CG2496 from Corynebacterium glutamicum and the N-terminal domain comprising residues 35-182 of the 435-residue protein PG0361 from Porphyromonas gingivalis both exhibit an a/ß fold comprised of a four-stranded ß-sheet, thre ...201122198206
Improving protein secretion of a transglutaminase-secreting Corynebacterium glutamicum recombinant strain on the basis of (13)C metabolic flux analysis.Corynebacterium glutamicum is known as a host species for amino acid production. This microorganism was recently noticed as a host that produces secreted proteins. In this study, we performed (13)C metabolic flux analysis ((13)C-MFA) on a recombinant C. glutamicum strain that secretes a heterologous transglutaminase (TGase) to improve TGase secretion. For the (13)C-MFA of a TGase-secreting C. glutamicum strain in batch cultivation, a (13)C-labeling experiment and measurement of mass isotopomer d ...201121903468
Corynebacterium glutamicum survives arsenic stress with arsenate reductases coupled to two distinct redox mechanisms.Arsenate reductases (ArsCs) evolved independently as a defence mechanism against toxic arsenate. In the genome of Corynebacterium glutamicum, there are two arsenic resistance operons (ars1 and ars2) and four potential genes coding for arsenate reductases (Cg_ArsC1, Cg_ArsC2, Cg_ArsC1' and Cg_ArsC4). Using knockout mutants, in vitro reconstitution of redox pathways, arsenic measurements and enzyme kinetics, we show that a single organism has two different classes of arsenate reductases. Cg_ArsC1 ...201122032722
deletion of the aconitase gene in corynebacterium glutamicum causes strong selection pressure for secondary mutations inactivating citrate synthase.the aconitase gene acn of corynebacterium glutamicum is regulated by four transcriptional regulators, indicating that the synthesis of this enzyme is carefully controlled. to understand the causes for this elaborate regulation, the properties of the δacn-1 deletion mutant were analyzed in detail. the mutant was glutamate auxotrophic in glucose minimal medium, showed a strong growth defect, and secreted large amounts of acetate. none of these phenotypes could be complemented by plasmid-encoded ac ...201121984793
current knowledge on isobutanol production with escherichia coli, bacillus subtilis and corynebacterium glutamicum.due to steadily rising crude oil prices great efforts have been made to develop designer bugs for the fermentative production of higher alcohols, such as 2-methyl-1-butanol, 3-methyl-1-butanol and 2-methyl-1-propanol (isobutanol), which all possess quality characteristics comparable to traditional oil based fuels. the common metabolic engineering approach uses the last two steps of the ehrlich pathway, catalyzed by 2-ketoacid decarboxylase and an alcohol dehydrogenase converting the branched cha ...201122008938
improvement of the redox balance increases l-valine production by corynebacterium glutamicum under oxygen deprivation conditions.production of l-valine under oxygen deprivation conditions by corynebacterium glutamicum lacking the lactate dehydrogenase gene ldha and overexpressing the l-valine biosynthesis genes ilvbncde was repressed. this was attributed to imbalanced cofactor production and consumption in the overall l-valine synthesis pathway: two moles of nadh was generated and two moles of nadph was consumed per mole of l-valine produced from one mole of glucose. in order to solve this cofactor imbalance, the coenzyme ...201122138982
Phenotypic characterization of Corynebacterium glutamicum using elementary modes towards synthesis of amino acids.Elementary flux mode (EFM) analysis is a powerful tool to represent the metabolic network structure and can be further utilized for flux analysis. The method enables characterization and quantification of feasible phenotypes in microbes. EFM analysis was employed to characterize the phenotype of Corynebacterium glutamicum to yield various amino acids. The metabolic network of C. glutamicum yielded 62 elementary modes by incorporating the accumulation of amino acids namely, lysine, alanine, valin ...201122132055
genetic and biochemical characterization of corynebacterium glutamicum atp phosphoribosyltransferase and its three mutants resistant to feedback inhibition by histidine.atp phosphoribosyltransferase (atp-prt) catalyzes the condensation of atp and prpp at the first step of histidine biosynthesis and is regulated by a feedback inhibition from product histidine. here, we report the genetic and biochemical characterization of such an enzyme, hisg(cg), from corynebacterium glutamicum, including site-directed mutagenesis of the histidine-binding site for the first time. gene disruption and complementation experiments showed that hisg(cg) is essential for histidine bi ...201122172596
Ethambutol-mediated cell wall modification in recombinant Corynebacterium glutamicum increases the biotransformation rates of cyclohexanone derivatives.The effects of structural modification of cell wall on the biotransformation capability by recombinant Corynebacterium glutamicum cells, expressing the chnB gene encoding cyclohexanone monooxygenase of Acinetobacter calcoaceticus NCIMB 9871, were investigated. Baeyer-Villiger oxygenation of 2-(2'-acetoxyethyl) cyclohexanone (MW 170 Da) into R-7-(2'-acetoxyethyl)-2-oxepanone was used as a model reaction. The whole-cell biotransformation followed Michaelis-Menten kinetics. The V (max) and K (S) va ...201121909677
Negative transcriptional control of biotin metabolism genes by the TetR-type regulator BioQ in biotin-auxotrophic Corynebacterium glutamicum ATCC 13032.Genomic context analysis in actinobacteria revealed that biotin biosynthesis and transport (bio) genes are co-localized in several genomes with a gene encoding a transcription regulator of the TetR protein family, now named BioQ. Comparative analysis of the upstream regions of bio genes identified the common 13-bp palindromic motif TGAAC-N3-GTTAC as candidate BioQ-binding site. To verify the role of BioQ in controlling the transcription of bio genes, a deletion in the bioQ coding region (cg2309) ...201122178235
mechanism of increased respiration in an h(+)-atpase-defective mutant of corynebacterium glutamicum.we previously reported that a spontaneous h(+)-atpase-defective mutant of corynebacterium glutamicum, f172-8, derived from c. glutamicum atcc 14067, showed enhanced glucose consumption and respiration rates. to investigate the genome-based mechanism of enhanced respiration rate in such c. glutamicum mutants, a-1, an h(+)-atpase-defective mutant derived from c. glutamicum atcc 13032, which harbors the same point mutation as f172-8, was used in this study. a-1 showed similar fermentation profiles ...201122188772
Structure of a highly NADP+-specific isocitrate dehydrogenase.Isocitrate dehydrogenase catalyzes the first oxidative and decarboxylation steps in the citric acid cycle. It also lies at a crucial bifurcation point between CO2-generating steps in the cycle and carbon-conserving steps in the glyoxylate bypass. Hence, the enzyme is a focus of regulation. The bacterial enzyme is typically dependent on the coenzyme nicotinamide adenine dinucleotide phosphate. The monomeric enzyme from Corynebacterium glutamicum is highly specific towards this coenzyme and the su ...201121931217
Enzymatic synthesis of S-adenosylhomocysteine: immobilization of recombinant S-adenosylhomocysteine hydrolase from Corynebacterium glutamicum (ATCC 13032).Recombinant S-adenosylhomocysteine hydrolase from Corynebacterium glutamicum (CgSAHase) was covalently bound to Eupergit® C. The maximum yield of bound protein was 91% and the catalytic efficiency was 96.9%. When the kinetic results for the immobilized enzyme were compared with those for the soluble enzyme, no decrease in the catalytic efficiency of the former was detected. Both soluble and immobilized enzymes showed similar optimum pH and temperature ranges. The reuse of immobilized CgSAHase ca ...201122202964
Purification, crystallization and preliminary X-ray diffraction studies of the arsenic repressor ArsR from Corynebacterium glutamicum.ArsR is a member of the SmtB/ArsR family of metalloregulatory proteins that regulate prokaryotic arsenic-resistance operons. Here, the crystallization and preliminary X-ray diffraction studies of a cysteine-free derivative of ArsR from Corynebacterium glutamicum (CgArsR-C15/16/55S) are reported. CgArsR-C15/16/55S was expressed, purified, crystallized and X-ray diffraction data were collected to 1.86 Å resolution. The protein crystallized in a tetragonal space group (P4), with unit-cell parameter ...201122139180
Corynebacterium glutamicum whcB, a stationary phase-specific regulatory gene.The function of whcB, one of the four whiB homologues of Corynebacterium glutamicum, was assessed. Cells carrying the P(180) -whcB clone, and thus overexpressing the whcB gene, showed retarded growth, probably due to increased sensitivity to oxidants, whereas cells lacking whcB (?whcB) did not. However, growth retardation was not observed in cells with additionally whcE deleted. Furthermore, the ?whcE phenotype, characterized by slow growth and sensitivity to oxidants, was reversed in cells carr ...201122098456
Engineered Corynebacterium glutamicum as an endotoxin-free platform strain for lactate-based polyester production.The first biosynthetic system for lactate (LA)-based polyesters was previously created in recombinant Escherichia coli (Taguchi et al. 2008). Here, we have begun efforts to upgrade the prototype polymer production system to a practical stage by using metabolically engineered Gram-positive bacterium Corynebacterium glutamicum as an endotoxin-free platform. We designed metabolic pathways in C. glutamicum to generate monomer substrates, lactyl-CoA (LA-CoA), and 3-hydroxybutyryl-CoA (3HB-CoA), for t ...201122127753
genome sequence of corynebacterium glutamicum s9114, a strain for industrial production of glutamate.here we report the genome sequence of corynebacterium glutamicum s9114, an industrial producer widely used in production of glutamate in china. preliminary comparison with the sequences of the corynebacterium glutamicum strains atcc 13032 and r revealed some notable mutagenesis that might be related to the high yield of glutamate.201121994927
sigma factors and promoters in corynebacterium glutamicum.the corynebacterium glutamicum genome codes for 7 sigma subunits (factors) of rna polymerase (rnap): primary sigma factor siga (s(a)), primary-like sigb and 5 other alternative sigma factors (sigc, sigd, sige, sigh and sigm). each sigma factor is responsible for recognizing promoters of genes belonging to a regulon (sigmulon) involved in specific functions of the cell. most promoters of c. glutamicum housekeeping genes are recognized by rnap+s(a), whereas s(b) is involved in transcription of a l ...201121277915
transcriptional regulators of multiple genes involved in carbon metabolism in corynebacterium glutamicum.corynebacterium glutamicum, a high-gc gram-positive soil bacterium, has been used in development of bioprocesses for production of various compounds such as amino acids, organic acids, and alcohols. recently, several transcriptional regulators, each of which is involved in multiple carbon metabolic pathways in this bacterium, have been identified and characterized. these regulators appear to form a complicated network mediating coordinated expression of a number of metabolic genes for efficient ...201121277916
structural asymmetry in a trimeric na+/betaine symporter, betp, from corynebacterium glutamicum.the na(+)-coupled symporter betp catalyzes the uptake of the compatible solute betaine in the soil bacterium corynebacterium glutamicum. betp also senses hyperosmotic stress and regulates its own activity in response to stress level. we determined a three-dimensional (3d) map (at 8 å in-plane resolution) of a constitutively active mutant of betp in a c. glutamicum membrane environment by electron cryomicroscopy of two-dimensional crystals. the map shows that the constitutively active mutant, whi ...201121281647
impact of improved potassium accumulation on ph homeostasis, membrane potential adjustment and survival of corynebacterium glutamicum.metal ion uptake is crucial for all living cells and an essential part of cellular bioenergetic homeostasis. in this study the uptake and the impact of the most abundant internal cation, potassium, were investigated in actinobacteria, a group of high g+c gram-positives with a number of prominent biotechnologically and medically important members. genome analyses revealed a variety of different potassium uptake systems in this monophyletic group ranging from potassium channels common in virtually ...201121295539
metabolic engineering of corynebacterium glutamicum for production of 1,5-diaminopentane from hemicellulose.in the present work, the bio-based production of 1,5-diaminopentane (cadaverine), an important building block for bio-polyamides, was extended to hemicellulose a non-food raw material. for this purpose, the metabolism of 1,5-diaminopentane-producing corynebacterium glutamicum was engineered to the use of the c(5) sugar xylose. this was realized by heterologous expression of the xyla and xylb genes from escherichia coli, mediating the conversion of xylose into xylulose 5-phosphate (an intermediat ...201121298810
glutamate production from ß-glucan using endoglucanase-secreting corynebacterium glutamicum.we demonstrate glutamate production from ß-glucan using endoglucanase (eg)-expressing corynebacterium glutamicum. the signal sequence tora derived from escherichia coli k12, which belongs to the tat pathway, was suitable for secreting eg of clostridium thermocellum using c. glutamicum as a host. using the tora signal sequence, endoglucanase from clostridium cellulovorans 743b was successfully expressed, and the secreted eg produced 123 mg of reducing sugar from 5 g of ß-glucan at 30 °c for 72 h, ...201121305281
a new pathway for poly(3-hydroxybutyrate) production in escherichia coli and corynebacterium glutamicum by functional expression of a new acetoacetyl-coenzyme a synthase.a biosynthetic pathway for poly(3-hydroxybutyrate) [p(3hb)] was developed in escherichia coli and corynebacterium glutamicum by an acetoacetyl-coenzyme a (coa) synthase (aacs) recently isolated from terpenoid-producing streptomyces sp. strain cl190. expression of aacs led to significant productions of p(3hb) in e. coli (10.5 wt %) and c. glutamicum (19.7 wt %).201121307588
control of adha and sucr expression by the sucr regulator in corynebacterium glutamicum.the alcohol dehydrogenase gene adha in corynebacterium glutamicum is subject to a complex carbon source-dependent regulation mediated by rama, ramb and glxr. in this study we identified sucr as the fourth transcriptional regulator involved in expression control of the adha gene. sucr specifically binds to the adha promoter and acts as transcriptional repressor independent of the carbon source used. furthermore, we found that sucr negatively controls the expression of its own gene. this negative ...201121320555
gene expression profiling of corynebacterium glutamicum during anaerobic nitrate respiration: induction of the sos response for cell survival.the gene expression profile of corynebacterium glutamicum under anaerobic nitrate respiration revealed marked differences in the expression levels of a number of genes involved in a variety of cellular functions, including carbon metabolism and respiratory electron transport chain, compared to the profile under aerobic conditions using dna microarrays. many sos genes were upregulated by the shift from aerobic to anaerobic nitrate respiration. an elongated cell morphology, similar to that induced ...201121239583
from zero to hero--design-based systems metabolic engineering of corynebacterium glutamicum for l-lysine production.here, we describe the development of a genetically defined strain of l-lysine hyperproducing corynebacterium glutamicum by systems metabolic engineering of the wild type. implementation of only 12 defined genome-based changes in genes encoding central metabolic enzymes redirected major carbon fluxes as desired towards the optimal pathway usage predicted by in silico modeling. the final engineered c. glutamicum strain was able to produce lysine with a high yield of 0.55 g per gram of glucose, a t ...201121241816
positive transcriptional control of the pyridoxal phosphate biosynthesis genes pdxst by the mocr-type regulator pdxr of corynebacterium glutamicum atcc 13032.the pdxr (cg0897) gene of corynebacterium glutamicum atcc 13032 encodes a regulatory protein belonging to the mocr subfamily of gntr-type transcription regulators and consisting of an amino-terminal winged helix-turn-helix dna-binding domain and a carboxy-terminal aminotransferase-like domain. a defined deletion in the pdxr gene resulted in the decreased expression of the divergently orientated pdxst genes coding for the subunits of pyridoxal 5'-phosphate synthase. the pdxst mutant c. glutamicum ...201120847010
mutational analysis of splicing activities of ribonucleotide reductase α subunit protein from lytic bacteriophage p1201.a cp1201 rir1 intein is found in the ribonucleotide reductase alpha subunit (rnr α subunit) protein of lytic bacteriophage p1201 from corynebacterium glutamicum nchu 87078. this intein can be over-expressed and spliced in escherichia coli novablue cells. mutations of c539, the n-terminal residue of the c-extein in the cp1201 rir1 protein, led to the changes of pattern and level of protein-splicing activities. a g392s variant was found to be a temperature-sensitive protein with complete splicing ...201121210121
assessment of bacterial diversity in the cattle tick rhipicephalus (boophilus) microplus through tag-encoded pyrosequencing.ticks are regarded as the most relevant vectors of disease-causing pathogens in domestic and wild animals. the cattle tick, rhipicephalus (boophilus) microplus, hinders livestock production in tropical and subtropical parts of the world where it is endemic. tick microbiomes remain largely unexplored. the objective of this study was to explore the r. microplus microbiome by applying the bacterial 16s tag-encoded flx-titanium amplicon pyrosequencing (btefap) technique to characterize its bacterial ...201121211038
control of heme homeostasis in corynebacterium glutamicum by the two-component system hrrsa.the response regulator hrra of the hrrsa two-component system (previously named cgtsr11) was recently found to be repressed by the global iron-dependent regulator dtxr in corynebacterium glutamicum. here, we provide evidence that hrra mediates heme-dependent gene regulation in this nonpathogenic soil bacterium. growth experiments and dna microarray analysis revealed that c. glutamicum is able to use hemin as an alternative iron source and emphasize the involvement of the putative hemin abc trans ...201121217007
escherichia coli w as a new platform strain for the enhanced production of l-valine by systems metabolic engineering.a less frequently employed escherichia coli strain w, yet possessing useful metabolic characteristics such as less acetic acid production and high l-valine tolerance, was metabolically engineered for the production of l-valine. the ilva gene was deleted to make more pyruvate, a key precursor for l-valine, available for enhanced l-valine biosynthesis. the laci gene was deleted to allow constitutive expression of genes under the tac or trc promoter. the ilvbn(mut) genes encoding feedback-resistant ...201121191998
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