Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
genetic characterization of 4-cresol catabolism in corynebacterium glutamicum.corynebacterium glutamicum uses 4-cresol as sole carbon source for growth. protocatechuate 3,4-dioxygenase activity had been detected when c. glutamicum was grown with 4-cresol. in this work, we found that 4-cresol was catabolized via 4-hydroxybenzoate and protocatechuate as intermediate metabolites, and a genetic cluster called cre (designated for 4-cresol, creabcdefghir, tagged as ncgl0521-ncgl0531 in ncbi) was identified. the cre gene cluster comprises of 11 genes, and six of them were experi ...201424480572
application of a genetically encoded biosensor for live cell imaging of l-valine production in pyruvate dehydrogenase complex-deficient corynebacterium glutamicum strains.the majority of biotechnologically relevant metabolites do not impart a conspicuous phenotype to the producing cell. consequently, the analysis of microbial metabolite production is still dominated by bulk techniques, which may obscure significant variation at the single-cell level. in this study, we have applied the recently developed lrp-biosensor for monitoring of amino acid production in single cells of gradually engineered l-valine producing corynebacterium glutamicum strains based on the p ...201424465669
role of flavohaemoprotein hmp and nitrate reductase narghji of corynebacterium glutamicum for coping with nitrite and nitrosative stress.the influence of nitrate and nitrite on growth of corynebacterium glutamicum under aerobic conditions in shake flasks was analysed. when dissolved oxygen became limiting at higher cell densities, nitrate was reduced almost stoichiometrically to nitrite by nitrate reductase (narghji). the nitrite concentration also declined slowly, presumably as a result of several reactions including reduction to nitric oxide by a side-activity of nitrate reductase. the flavohaemoglobin gene hmp was most strongl ...201424237595
assessment of robustness against dissolved oxygen/substrate oscillations for c. glutamicum dm1933 in two-compartment bioreactor.corynebacterium glutamicum is an important organism for industrial biotechnology; particularly, in amino acid production (e.g. l-lysine). production scales often reach reactor working volumes of several hundred cubic meters, which triggers inhomogeneous distribution of substrates and dissolved gasses due to increasing mixing times. individual cells which follow the flow profile through the reactor are experiencing oscillating microenvironments. oscillations can have an influence on the process p ...201424218302
metabolic engineering of corynebacterium glutamicum for 2-ketoisocaproate production.2-ketoisocaproate (kic) is used as a therapeutic agent, and a kic-producing organism may serve as a platform for products deriving from this 2-keto acid. we engineered corynebacterium glutamicum for the production of kic from glucose by deletion of ltbr and ilve, encoding the transcriptional repressor ltbr and transaminase b, respectively, and additional overexpression of ilvbncd, encoding acetohydroxyacid synthase, acetohydroxyacid isomeroreductase, and dihydroxyacid dehydratase. the kic-produc ...201424169948
analysis of sos-induced spontaneous prophage induction in corynebacterium glutamicum at the single-cell level.the genome of the gram-positive soil bacterium corynebacterium glutamicum atcc 13032 contains three integrated prophage elements (cgp1 to -3). recently, it was shown that the large lysogenic prophage cgp3 (∼187 kbp) is excised spontaneously in a small number of cells. in this study, we provide evidence that a spontaneously induced sos response is partly responsible for the observed spontaneous cgp3 induction. whereas previous studies focused mainly on the induction of prophages at the population ...201424163339
deregulation of feedback inhibition of phosphoenolpyruvate carboxylase for improved lysine production in corynebacterium glutamicum.allosteric regulation of phosphoenolpyruvate carboxylase (pepc) controls the metabolic flux distribution of anaplerotic pathways. in this study, the feedback inhibition of corynebacterium glutamicum pepc was rationally deregulated, and its effect on metabolic flux redistribution was evaluated. based on rational protein design, six pepc mutants were designed, and all of them showed significantly reduced sensitivity toward aspartate and malate inhibition. introducing one of the point mutations (n9 ...201424334667
pushing product formation to its limit: metabolic engineering of corynebacterium glutamicum for l-leucine overproduction.using metabolic engineering, an efficient l-leucine production strain of corynebacterium glutamicum was developed. in the wild type of c. glutamicum, the leua-encoded 2-isopropylmalate synthase (ipms) is inhibited by low l-leucine concentrations with a k(i) of 0.4 mm. we identified a feedback-resistant imps variant, which carries two amino acid exchanges (r529h, g532d). the corresponding leua(fbr) gene devoid of the attenuator region and under control of a strong promoter was integrated in one, ...201424333966
increase in lactate yield by growing corynebacterium glutamicum in a bioelectrochemical reactor.under conditions conductive to growth, corynebacterium glutamicum showed higher lactate yield from glucose (1.62 ± 0.04) in a bioelectrochemical reactor including 0.2 mm of anthraquinone 2,6-disulfonate with the electrode potential regulated at -0.6 v (vs. ag/agcl) than in a non-regulated environment (1.10 ± 0.03), clarifying that low cathodic potential is beneficial for lactate production.201424315531
corynebacterium glutamicum arnr controls expression of nitrate reductase operon narkghji and nitric oxide (no)-detoxifying enzyme gene hmp in an no-responsive manner.corynebacterium glutamicum arnr is a novel transcriptional regulator that represses expression of the nitrate reductase operon narkghji and the nitric oxide (no)-detoxifying flavohemoglobin gene hmp under aerobic conditions. in a previous study, we showed that arnr-mediated repression is relieved during anaerobic nitrate respiration, but we could not pinpoint the specific signal that arnr senses. in this study, we show that in the absence of nitrate, arnr-mediated repression is maintained under ...201424142248
improved succinate production in corynebacterium glutamicum by engineering glyoxylate pathway and succinate export system.a dual route for anaerobic succinate production was engineered into corynebacterium glutamicum. the glyoxylate pathway was reconstructed by overexpressing isocitrate lyase, malate synthase and citrate synthase. the engineered strain produced succinate with a yield of 1.34 mol (mol glucose)(-1). further overexpression of succinate exporter, suce, increased succinate yield to 1.43 mol (mol glucose)(-1). metabolic flux analysis revealed that the glyoxylate pathway was further activated by engineeri ...201424129953
beyond growth rate 0.6: what drives corynebacterium glutamicum to higher growth rates in defined medium.in a former study we showed that corynebacterium glutamicum grows much faster in defined cgxii glucose medium when growth was initiated in highly diluted environments [grünberger et al. (2013b) biotechnol bioeng]. here we studied the batch growth of c. glutamicum in cgxii at a comparable low starting biomass concentration of od ≈ 0.005 in more detail. during bioreactor cultivations a bi-phasic growth behavior with changing growth rates was observed. initially the culture grew with μˆ=0.61±0.02 h ...201423996851
effect of biotin on transcription levels of key enzymes and glutamate efflux in glutamate fermentation by corynebacterium glutamicum.biotin is an important factor affecting the performance of glutamate fermentation by biotin auxotrophic corynebacterium glutamicum and glutamate is over-produced only when initial biotin content is controlled at suitable levels or initial biotin is excessive but with tween 40 addition during fermentation. the transcription levels of key enzymes at pyruvate, isocitrate and α-ketoglutarate metabolic nodes, as well as transport protein (tp) of glutamate were investigated under the conditions of var ...201423990041
stimulus analysis of betp activation under in vivo conditions.the secondary active, na(+) coupled glycine betaine carrier betp from corynebacterium glutamicum betp was shown to harbor two different functions, transport catalysis (betaine uptake) and stimulus sensing, as well as activity regulation in response to hyperosmotic stress. by analysis in a reconstituted system, the rise in the cytoplasmic k(+) concentration was identified as a primary stimulus for betp activation. we have now studied regulation of betp in vivo by independent variation of both the ...201424384063
nrdh redoxin enhances resistance to multiple oxidative stresses by acting as a peroxidase cofactor in corynebacterium glutamicum.nrdh redoxins are small protein disulfide oxidoreductases behaving like thioredoxins but sharing a high amino acid sequence similarity to glutaredoxins. although nrdh redoxins are supposed to be another candidate in the antioxidant system, their physiological roles in oxidative stress remain unclear. in this study, we confirmed that the corynebacterium glutamicum nrdh redoxin catalytically reduces the disulfides in the class ib ribonucleotide reductases (rnr), insulin and 5,5'-dithiobis-(2-nitro ...201424375145
reducing lactate secretion by ldha deletion in l-glutamate- producing strain corynebacterium glutamicum gdk-9.l-lactate is one of main byproducts excreted in to the fermentation medium. to improve l-glutamate production and reduce l-lactate accumulation, l-lactate dehydrogenase-encoding gene ldha was knocked out from l-glutamate producing strain corynebacterium glutamicum gdk-9, designated gdk-9δldha. gdk-9δldha produced approximately 10.1% more l-glutamate than the gdk-9, and yielded lower levels of such by-products as α-ketoglutarate, l-lactate and l-alanine. since dissolved oxygen (do) is one of main ...201425763057
characterization of a corynebacterium glutamicum dnab mutant that shows temperature-sensitive growth and mini-cell formation.corynebacterium glutamicum is known to perform a unique form of cell division called post-fission snapping division. in order to investigate the mechanism of cell division of this bacterium, we isolated temperature-sensitive mutants from c. glutamicum wild-type strain atcc 31831, and found that one of them, m45, produced high frequencies of mini-cells with no nucleoids. cell pairs composed of an elongated cell, with one nucleoid, connected to a mini-cell, with no nucleoids, were occasionally obs ...201425141796
process inhomogeneity leads to rapid side product turnover in cultivation of corynebacterium glutamicum.corynebacterium glutamicum has large scale industrial applications in the production of amino acids and the potential to serve as a platform organism for new products. this means the demand for industrial process development is likely to increase. however, large scale cultivation conditions differ from laboratory bioreactors, mostly due to the formation of concentration gradients at the industrial scale. this leads to an oscillating supply of oxygen and nutrients for microorganisms with uncertai ...201424410842
identification of low-molecular-weight compounds inhibiting growth of corynebacteria: potential lead compounds for antibiotics.the bacterial genus corynebacteria contains several pathogenic species that cause diseases such as diphtheria in humans and "cheesy gland" in goats and sheep. thus, identifying new therapeutic targets to treat corynebacteria infections is both medically and economically important. cg2496, a functionally uncharacterized protein from corynebacterium glutamicum, was evaluated using an nmr ligand-affinity screen. a total of 11 compounds from a library of 460 biologically active compounds were shown ...201424403054
idsa is the major geranylgeranyl pyrophosphate synthase involved in carotenogenesis in corynebacterium glutamicum.corynebacterium glutamicum, a yellow-pigmented soil bacterium that synthesizes the rare cyclic c50 carotenoid decaprenoxanthin and its glucosides, has been engineered for the production of various carotenoids. crte was assumed to be the major geranylgeranyl pyrophosphate (ggpp) synthase in carotenogenesis; however, deletion of crte did not abrogate carotenoid synthesis. in silico analysis of the repertoire of prenyltransferases encoded by the c. glutamicum genome revealed two candidate ggpps gen ...201425181035
taking control over control: use of product sensing in single cells to remove flux control at key enzymes in biosynthesis pathways.enzymes initiating the biosynthesis of cellular building blocks are frequently inhibited by the end-product of the respective pathway. here we present an approach to rapidly generate sets of enzymes overriding this control. it is based on the in vivo detection of the desired end-product in single cells using a genetically encoded sensor. the sensor transmits intracellular product concentrations into a graded optical output, thus enabling ultrahigh-throughput screens by facs. we randomly mutageni ...201423829416
protein s-mycothiolation functions as redox-switch and thiol protection mechanism in corynebacterium glutamicum under hypochlorite stress.protein s-bacillithiolation was recently discovered as important thiol protection and redox-switch mechanism in response to hypochlorite stress in firmicutes bacteria. here we used transcriptomics to analyze the naocl stress response in the mycothiol (msh)-producing corynebacterium glutamicum. we further applied thiol-redox proteomics and mass spectrometry (ms) to identify protein s-mycothiolation.201423886307
a role of the transcriptional regulator lldr (ncgl2814) in glutamate metabolism under biotin-limited conditions in corynebacterium glutamicum.corynebacterium glutamicum is a gram-positive, rod-shaped, aerobic bacterium used for the fermentative production of l-glutamate. lldr (ncgl2814) is known as a repressor for ldha and lldd encoding lactate dehydrogenases. ldha is responsible for production of l-lactate, while lldd is for its assimilation. since l-lactate production was observed as a by-product of glutamate production under biotin-limited conditions, lldr might play a regulatory role in the glutamate metabolism. here for the first ...201323863291
platform engineering of corynebacterium glutamicum with reduced pyruvate dehydrogenase complex activity for improved production of l-lysine, l-valine, and 2-ketoisovalerate.exchange of the native corynebacterium glutamicum promoter of the acee gene, encoding the e1p subunit of the pyruvate dehydrogenase complex (pdhc), with mutated dapa promoter variants led to a series of c. glutamicum strains with gradually reduced growth rates and pdhc activities. upon overexpression of the l-valine biosynthetic genes ilvbnce, all strains produced l-valine. among these strains, c. glutamicum acee a16 (pjc4 ilvbnce) showed the highest biomass and product yields, and thus it was f ...201323835179
a propionate-inducible expression system based on the corynebacterium glutamicum prpd2 promoter and prpr activator and its application for the redirection of amino acid biosynthesis pathways.a novel expression system for corynebacterium glutamicum, based on the transcriptional activator of propionate metabolism genes prpr and its target promoter/operator sequence, was developed and tested. the activator prpr is co-activated by propionate added to the growth medium. in a minimal medium a propionate concentration of only 1 mg l⁻¹ was found to be sufficient for full induction (up to 120-fold) of its native target, the propionate metabolism operon prpdbc2. then, an artificial transcript ...201322982516
single-step production of polyhydroxybutyrate from starch by using α-amylase cell-surface displaying system of corynebacterium glutamicum.direct polyhydroxybutyrate (phb) production from starch was for the first time achieved using engineered corynebacterium glutamicum expressing phb biosynthetic genes and displaying α-amylase on its cell surface. the engineered strain accumulated 6.4 wt% phb from starch which was higher than that obtained from glucose (4.9 wt%).201322959444
production of l-lysine on different silage juices using genetically engineered corynebacterium glutamicum.corynebacterium glutamicum, the best established industrial producer organism for lysine was genetically modified to allow the production of lysine on grass and corn silages. the resulting strain c. glutamicum lysc(fbr)dld(psod)pyc(psod)male(psod)fbp(psod)gapx(psod) was based on earlier work (neuner and heinzle, 2011). that mutant carries a point mutation in the aspartokinase (lysc) regulatory subunit gene as well as overexpression of d-lactate dehydrogenase (dld), pyruvate carboxylase (pyc) and ...201322898177
beyond growth rate 0.6: corynebacterium glutamicum cultivated in highly diluted environments.fast growth of industrial microorganisms, such as corynebacterium glutamicum, is a direct amplifier for the productivity of any growth coupled or decoupled production process. recently, it has been shown that c. glutamicum when grown in a novel picoliter bioreactor (plbr) exhibits a 50% higher growth rate compared to a 1 l batch cultivation [grünberger et al. (2012) lab chip]. we here compare growth of c. glutamicum with glucose as substrate at different scales covering batch cultivations in the ...201322890752
glucosamine as carbon source for amino acid-producing corynebacterium glutamicum.corynebacterium glutamicum grows with a variety of carbohydrates and carbohydrate derivatives as sole carbon sources; however, growth with glucosamine has not yet been reported. we isolated a spontaneous mutant (m4) which is able to grow as fast with glucosamine as with glucose as sole carbon source. glucosamine also served as a combined source of carbon, energy and nitrogen for the mutant strain. characterisation of the m4 mutant revealed a significantly increased expression of the nagb gene en ...201322854894
modeling and optimization of glutamic acid production using mixed culture of corynebacterium glutamicum ncim2168 and pseudomonas reptilivora ncim2598.in this study, a hybrid system of response surface methodology followed by genetic algorithm has been adopted to optimize the production medium for l-glutamic acid fermentation with mixed cultures of corynebacterium glutamicum and pseudomonas reptilovora. the optimal combination of media components for maximal production of l-glutamic acid was found to be 49.99 g l(-1) of glucose, 10 g l(-1) of urea, 18.06% (v/v) of salt solution, and 4.99% (v/v) of inoculum size. the experimental glutamic acid ...201323768112
microarray studies reveal a 'differential response' to moderate or severe heat shock of the hrca- and hspr-dependent systems in corynebacterium glutamicum.this article has been retracted at the request of microbiology because identical bands for the 16s rrna probe controls in the northern blots were reported to correspond to experiments using different strains and experimental conditions in articles published in this journal and in journal of bacteriology over a period of 5 years.201323754843
transcriptional analysis of the f0f1 atpase operon of corynebacterium glutamicum atcc 13032 reveals strong induction by alkaline ph.this article has been retracted at the request of microbiology because identical bands for the 16s rrna probe controls in the northern blots were reported to correspond to experiments using different strains and experimental conditions in articles published in this journal and in journal of bacteriology over a period of 5 years.201323754842
direct l-lysine production from cellobiose by corynebacterium glutamicum displaying beta-glucosidase on its cell surface.we constructed beta-glucosidase (bgl)-displaying corynebacterium glutamicum, and direct l-lysine fermentation from cellobiose was demonstrated. after screening active bgls, sde1394, which is a bgl from saccharophagus degradans, was successfully displayed on the c. glutamicum cell surface using porin as an anchor protein, and cellobiose was directly assimilated as a carbon source. the optical density at 600 nm of bgl-displaying c. glutamicum grown on cellobiose as a carbon source reached 23.5 aft ...201323749228
metabolic evolution of corynebacterium glutamicum for increased production of l-ornithine.l-ornithine is effective in the treatment of liver diseases and helps strengthen the heart. the commercial applications mean that efficient biotechnological production of l-ornithine has become increasingly necessary. adaptive evolution strategies have been proven a feasible and efficient technique to achieve improved cellular properties without requiring metabolic or regulatory details of the strain. the evolved strains can be further optimised by metabolic engineering. thus, metabolic evolutio ...201323725060
identification of a gene involved in plasmid structural instability in corynebacterium glutamicum.expression plasmids that facilitate production of bio-based products are susceptible to toxic effects that frequently affect plasmid structural stability in recombinant microbial cells. in order to enhance plasmid stability in recombinant corynebacterium glutamicum, an expression plasmid containing genes of the clostridium acetobutylicum butyryl-coa synthesis operon with high structural instability within wild-type c. glutamicum was employed. from a total of 133 mutants exhibiting disruptions in ...201323703324
a mutational analysis of the active site loop residues in cis-3-chloroacrylic acid dehalogenase.cis-3-chloroacrylic acid dehalogenase (cis-caad) from pseudomonas pavonaceae 170 and a homologue from corynebacterium glutamicum designated cg10062 are 34% identical in sequence (54% similar). the former catalyzes a key step in a bacterial catabolic pathway for the nematocide 1,3-dichloropropene, whereas the latter has no known biological activity. although cg10062 has the six active site residues (pro-1, his-28, arg-70, arg-73, tyr-103, and glu-114) that are critical for cis-caad activity, it s ...201323692140
enhancing the supply of oxaloacetate for l-glutamate production by pyc overexpression in different corynebacterium glutamicum.during l-glutamate production, phosphoenolpyruvate carboxylase and pyruvate carboxylase (pcx) play important roles in supplying oxaloacetate to the tricarboxylic acid cycle. to explore the significance of pcx for l-glutamate overproduction, the pyc gene encoding pcx was amplified in corynebacterium glutamicum gdk-9 triggered by biotin limitation and cn1021 triggered by a temperature shock, respectively. in the fed-batch cultures, gdk-9pxmj19pyc exhibited 7.4 % lower l-alanine excretion and no im ...201323690048
pcgr2 copy number depends on the par locus that forms a parc-parb-dna partition complex in corynebacterium glutamicum.to characterize the par system of corynebacterium glutamicum pcgr2 and to manipulate the par components to effectively manipulate plasmid copy number.201323683072
heat shock proteome analysis of wild-type corynebacterium glutamicum atcc 13032 and a spontaneous mutant lacking groel1, a dispensable chaperone. 201323661687
transcriptional analysis of the groes-groel1, groel2, and dnak genes in corynebacterium glutamicum: characterization of heat shock-induced promoters. 201323661686
cord factor (trehalose 6,6'-dimycolate) forms fully stable and non-permeable lipid bilayers required for a functional outer membrane.cord factor (trehalose 6,6'-dimycolate, tdm) is the major lipid in the outer membrane of corynebacteria and mycobacteria. although its role is well recognized in the immune response phenomena, its membrane biophysical properties remained largely unexplored and tdm has often been described as a detergent. we purified the main components of the outer membrane from corynebacterium glutamicum and analyzed their membrane forming properties. in mixture with endogenous cardiolipin, but not alone, the s ...201323643889
isolation of fully synthetic promoters for high-level gene expression in corynebacterium glutamicum.corynebacterium glutamicum is an important industrial organism that is widely used in the production of amino acids, nucleotides and vitamins. to extend its product spectrum and improve productivity, c. glutamicum needs to undergo further engineering, including the development of applicable promoter system. here, we isolated new promoters from the fully synthetic promoter library consisting of 70-bp random sequences in c. glutamicum. using green fluorescent protein (gfp) as a reporter, highly fl ...201323633298
recombineering in corynebacterium glutamicum combined with optical nanosensors: a general strategy for fast producer strain generation.recombineering in bacteria is a powerful technique for genome reconstruction, but until now, it was not generally applicable for development of small-molecule producers because of the inconspicuous phenotype of most compounds of biotechnological relevance. here, we establish recombineering for corynebacterium glutamicum using rect of prophage rac and combine this with our recently developed nanosensor technology, which enables the detection and isolation of productive mutants at the single-cell ...201323630315
proteome response of corynebacterium glutamicum to high concentration of industrially relevant c₄ and c₅ dicarboxylic acids.more than fifty years of industrial and scientific developments on the amino acid-producer strain corynebacterium glutamicum has generated an extremely huge knowledge highly applicable to the development of new products. despite the production of dicarboxylic acids has already been engineered in c. glutamicum, the effect caused by these acids at competitive industrial levels has not yet been described. thus, aspartic, fumaric, itaconic, malic and succinic acids have been tested on the growth of ...201323624027
oxyr acts as a transcriptional repressor of hydrogen peroxide-inducible antioxidant genes in corynebacterium glutamicum r.oxyr, a lysr-type transcriptional regulator, has been established as a redox-responsive activator of antioxidant genes in bacteria. this study shows that oxyr acts as a transcriptional repressor of kata, dps, ftn and cyda in corynebacterium glutamicum r. kata encodes h2o2-detoxifing enzyme catalase, dps and ftn are implicated in iron homeostasis and cyda encodes a subunit of cytochrome bd oxidase. quantitative rt-pcr analyses revealed that expression of kata and dps, but not of ftn and cyda, was ...201323621709
physiological roles of mycothiol in detoxification and tolerance to multiple poisonous chemicals in corynebacterium glutamicum.mycothiol (msh) plays important roles in maintaining cytosolic redox homeostasis and in adapting to reactive oxygen species in the high-(g + c)-content gram-positive actinobacteria. however, its physiological roles are ill defined compared to glutathione, the functional analog of msh in gram-negative bacteria and most eukaryotes. in this research, we explored the impact of intracellular msh on cellular physiology by using msh-deficient mutants in the model organism corynebacterium glutamicum. we ...201323615850
recovery of high-purity metallic pd from pd(ii)-sorbed biosorbents by incineration.this work reports a direct way to recover metallic palladium with high purity from pd(ii)-sorbed polyethylenimine-modified corynebacterium glutamicum biosorbent using a combined method of biosorption and incineration. this study is focused on the incineration part which affects the purity of recovered pd. the incineration temperature and the amount of pd loaded on the biosorbent were considered as major factors in the incineration process, and their effects were examined. the results showed that ...201323611701
regulatory interaction of the corynebacterium glutamicum whc genes in oxidative stress responses.in this study, we analyzed the regulatory interaction of the corynebacterium glutamicum whc genes that play roles in oxidative stress responses. we found that whce and whca transcription was minimal in the whcb-deleted mutant (δwhcb). however, whcb and whca transcription increased in the δwhce mutant during the log phase, whereas their transcription decreased during the stationary phase. in addition, cells carrying the p180-whcb vector, which showed retarded growth due to uncontrolled whcb overe ...201323608553
development of a secretion system for the production of heterologous proteins in corynebacterium glutamicum using the porin b signal peptide.corynebacterium glutamicum is one of the useful hosts for the secretory production of heterologous proteins because of intrinsic attributes such as the presence of few endogenous proteins and proteases in culture medium. here, we report the development of a new secretory system for the production of heterologous proteins by using the porin b (porb) signal peptide in c. glutamicum. we examined two different endoxylanases and an antibody fragment (scfv) as model proteins for secretory production. ...201323597779
oxygen supply in disposable shake-flasks: prediction of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growth.dissolved oxygen plays an essential role in aerobic cultivation especially due to its low solubility. under unfavorable conditions of mixing and vessel geometry it can become limiting. this, however, is difficult to predict and thus the right choice for an optimal experimental set-up is challenging. to overcome this, we developed a method which allows a robust prediction of the dissolved oxygen concentration during aerobic growth. this integrates newly established mathematical correlations for t ...201323592306
crystal and solution studies reveal that the transcriptional regulator acnr of corynebacterium glutamicum is regulated by citrate-mg2+ binding to a non-canonical pocket.corynebacterium glutamicum is an important industrial bacterium as well as a model organism for the order corynebacteriales, whose citric acid cycle occupies a central position in energy and precursor supply. expression of aconitase, which isomerizes citrate into isocitrate, is controlled by several transcriptional regulators, including the dimeric aconitase repressor acnr, assigned by sequence identity to the tetr family. we report the structures of acnr in two crystal forms together with ligan ...201323589369
maltose uptake by the novel abc transport system musefgk2i causes increased expression of ptsg in corynebacterium glutamicum.the gram-positive corynebacterium glutamicum efficiently metabolizes maltose by a pathway involving maltodextrin and glucose formation by 4-α-glucanotransferase, glucose phosphorylation by glucose kinases, and maltodextrin degradation via maltodextrin phosphorylase and α-phosphoglucomutase. however, maltose uptake in c. glutamicum has not been investigated. interestingly, the presence of maltose in the medium causes increased expression of ptsg in c. glutamicum by an unknown mechanism, although ...201323543710
kinetic and thermodynamic characterization of lysine production process in brevibacterium lactofermentum.detailed kinetic and thermodynamic parameters for lysine production from brevibacterium lactofermentum are investigated for the first time in this study. production of the essential amino acid, l-lysine, by b. lactofermentum was assessed in a flask and a continuously stirred tank fermentor (22 l). maximum lysine production was achieved after 40 h of growth and at 35 °c. the effect of different nitrogen sources such as nh(4)no(3), (nh(4))(2)so(4), (nh(4))(2)hpo(4), corn steep liquor, nano(3), and ...201323475286
systems metabolic engineering of xylose-utilizing corynebacterium glutamicum for production of 1,5-diaminopentane.the sustainable production of industrial platform chemicals is one of the great challenges facing the biotechnology field. ideally, fermentation feedstocks would rather rely on industrial waste streams than on food-based raw materials. corynebacterium glutamicum was metabolically engineered to produce the bio-nylon precursor 1,5-diaminopentane from the hemicellulose sugar xylose. comparison of a basic diaminopentane producer strain on xylose and glucose feedstocks revealed a 30% reduction in dia ...201323447448
proteome turnover in bacteria: current status for corynebacterium glutamicum and related bacteria.with the advent of high-resolution mass spectrometry together with sophisticated data analysis and interpretation algorithms, determination of protein synthesis and degradation rates (i.e. protein turnover) on a proteome-wide scale by employing stable isotope-labelled amino acids has become feasible. these dynamic data provide a deeper understanding of protein homeostasis and stress response mechanisms in microorganisms than well-established 'steady state' proteomics approaches. in this article, ...201323425033
conversion of corynebacterium glutamicum from an aerobic respiring to an aerobic fermenting bacterium by inactivation of the respiratory chain.in this study a comparative analysis of three corynebacterium glutamicum atcc 13032 respiratory chain mutants lacking either the cytochrome bd branch (δcydab), or the cytochrome bc1-aa3 branch (δqcr), or both branches was performed. the lack of cytochrome bd oxidase was inhibitory only under conditions of oxygen limitation, whereas the absence of a functional cytochrome bc1-aa3 supercomplex led to decreases in growth rate, biomass yield, respiration and proton-motive force (pmf) and a strongly i ...201323416842
media optimization of corynebacterium glutamicum for succinate production under oxygen-deprived condition.corynebacterium glutamicum is one of the well-studied industrial strain that is used for the production of nucleotides and amino acids. recently, it has also been studied as a possible producer of organic acids such as succinic acid, based on its ability to produce organic acids under an oxygen deprivation condition. in this study, we conducted the optimization of medium components for improved succinate production from c. glutamicum under an oxygen deprivation condition by plackett-burman desig ...201323412064
chromosome segregation impacts on cell growth and division site selection in corynebacterium glutamicum.spatial and temporal regulation of bacterial cell division is imperative for the production of viable offspring. in many rod-shaped bacteria, regulatory systems such as the min system and nucleoid occlusion ensure the high fidelity of midcell divisome positioning. however, regulation of division site selection in bacteria lacking recognizable min and nucleoid occlusion remains less well understood. here, we describe one such rod-shaped organism, corynebacterium glutamicum, which does not always ...201323405112
involvement of regulatory interactions among global regulators glxr, sugr, and rama in expression of rama in corynebacterium glutamicum.the central carbon metabolism genes in corynebacterium glutamicum are under the control of a transcriptional regulatory network composed of several global regulators. it is known that the promoter region of rama, encoding one of these regulators, interacts with its gene product, rama, as well as with the two other regulators, glxr and sugr, in vitro and/or in vivo. although rama has been confirmed to repress its own expression, the roles of glxr and sugr in rama expression have remained unclear. ...201323396909
phosphotransferase system-mediated glucose uptake is repressed in phosphoglucoisomerase-deficient corynebacterium glutamicum strains.corynebacterium glutamicum is particularly known for its industrial application in the production of amino acids. amino acid overproduction comes along with a high nadph demand, which is covered mainly by the oxidative part of the pentose phosphate pathway (ppp). in previous studies, the complete redirection of the carbon flux toward the ppp by chromosomal inactivation of the pgi gene, encoding the phosphoglucoisomerase, has been applied for the improvement of c. glutamicum amino acid production ...201323396334
the salicylate 1,2-dioxygenase as a model for a conventional gentisate 1,2-dioxygenase: crystal structures of the g106a mutant and its adducts with gentisate and salicylate.the salicylate 1,2-dioxygenase (sdo) from the bacterium pseudaminobacter salicylatoxidans bn12 is a versatile gentisate 1,2-dioxygenase (gdo) that converts both gentisate (2,5-dihydroxybenzoate) and various monohydroxylated substrates. several variants of this enzyme were rationally designed based on the previously determined enzyme structure and sequence differences between the sdo and the 'conventional' gdo from corynebacterium glutamicum. this was undertaken in order to define the structural ...201323384287
modification of histidine biosynthesis pathway genes and the impact on production of l-histidine in corynebacterium glutamicum.histidine biosynthesis in corynebacterium glutamicum is regulated not only by feedback inhibition by the first enzyme in the pathway, but also by repression control of the synthesis of the histidine enzymes. c. glutamicum histidine genes are located and transcribed in two unlinked loci, hiseg and hisdcb-orf1-orf2-hisha-impa-hisfi. we constructed plasmid pk18hisdptac to replace the native hisd promoter with the tac promoter, and overexpressed phosphoribosyl-atp-pyrophosphohydrolase, encoded by hi ...201323355034
increasing l-isoleucine production in corynebacterium glutamicum by overexpressing global regulator lrp and two-component export system brnfe.to increase the l-isoleucine production in corynebacterium glutamicum by overexpressing the global regulator lrp and the two-component export system brnfe.201323331988
characterization of shikimate dehydrogenase homologues of corynebacterium glutamicum.the function of three corynebacterium glutamicum shikimate dehydrogenase homologues, designated as qsud (cgr_0495), cgr_1216, and aroe (cgr_1677), was investigated. a disruptant of aroe required shikimate for growth, whereas a qsud-deficient strain did not grow in medium supplemented with either quinate or shikimate as sole carbon sources. there was no discernible difference in growth rate between wild-type and a cgr_1216-deficient strain. enzymatic assays showed that aroe both reduced 3-dehydro ...201323306642
corynebacterium glutamicum promoters: a practical approach.transcription initiation is the key step in gene expression in bacteria, and it is therefore studied for both theoretical and practical reasons. promoters, the traffic lights of transcription initiation, are used as construction elements in biotechnological efforts to coordinate 'green waves' in the metabolic pathways leading to the desired metabolites. detailed analyses of corynebacterium glutamicum promoters have already provided large amounts of data on their structures, regulatory mechanisms ...201323305350
adaptive evolution of corynebacterium glutamicum resistant to oxidative stress and its global gene expression profiling.corynebacterium glutamicum was adapted in a chemostat for 1,900 h with gradually increasing h2o2 stress to understand the oxidative stress response of an industrial host. after 411 generations of adaptation, c. glutamicum developed the ability to grow under stress of 10 mm h2o2, whereas the wild-type did not. the adapted strain also showed increased stress resistance to diamide and menadione, sds, tween 20, hcl, naoh, and ampicillin. a total of 1,180 genes in the rna-seq transcriptome analysis o ...201323288296
non-invasive online detection of microbial lysine formation in stirred tank bioreactors by using calorespirometry.non-invasive methods for online monitoring of biotechnological processes without compromising the integrity of the reactor system are very important to generate continuous data. even though calorimetry has been used in conventional biochemical analysis for decades, it has not yet been specifically applied for online detection of product formation at technical scale. thus, this article demonstrates a calorespirometric method for online detection of microbial lysine formation in stirred tank biore ...201323280310
monitoring of population dynamics of corynebacterium glutamicum by multiparameter flow cytometry.phenotypic variation of microbial populations is a well-known phenomenon and may have significant impact on the success of industrial bioprocesses. flow cytometry (fc) and the large repertoire of fluorescent dyes bring the high-throughput analysis of multiple parameters in single bacterial cells into reach. in this study, we evaluated a set of different fluorescent dyes for suitability in fc single cell analysis of the biotechnological platform organism corynebacterium glutamicum. already simple ...201323279937
bio-based production of organic acids with corynebacterium glutamicum.the shortage of oil resources, the steadily rising oil prices and the impact of its use on the environment evokes an increasing political, industrial and technical interest for development of safe and efficient processes for the production of chemicals from renewable biomass. thus, microbial fermentation of renewable feedstocks found its way in white biotechnology, complementing more and more traditional crude oil-based chemical processes. rational strain design of appropriate microorganisms has ...201323199277
ruthenium recovery from acetic acid waste water through sorption with bacterial biosorbent fibers.a fibrous bacterial biosorbent was developed to bind precious metal-organic complexes in batch and column processes. polyethylenimine (pei)-modified bacterial biosorbent fiber (pbbf) was prepared by spinning corynebacterium glutamicum biomass-chitosan blends, coating them with pei and cross-linking with glutaraldehyde. when an acetic acid waste solution containing 1822.9mg/l ru was used as a model waste solution, ru uptake by the pbbf was 16.5 times higher than that of the commercial ion exchang ...201323196218
influence of sigb inactivation on corynebacterium glutamicum protein secretion.the non-essential corynebacterium glutamicum sigma factor, sigb, modulates global gene expression during the transition from exponential growth to the stationary phase. utilizing a signal peptide derived from c. glutamicum r cgr_0949, a sigb disruption mutant able to secrete 3- to 5-fold more green fluorescence protein (gfp) and α-amylase than the wild type strain was isolated. the signal peptide selectively enabled the mutant to produce greater amounts of both proteins, which were in turn secre ...201323179627
secretory production of an fad cofactor-containing cytosolic enzyme (sorbitol-xylitol oxidase from streptomyces coelicolor) using the twin-arginine translocation (tat) pathway of corynebacterium glutamicum.carbohydrate oxidases are biotechnologically interesting enzymes that require a tightly or covalently bound cofactor for activity. using the industrial workhorse corynebacterium glutamicum as the expression host, successful secretion of a normally cytosolic fad cofactor-containing sorbitol-xylitol oxidase from streptomyces coelicolor was achieved by using the twin-arginine translocation (tat) protein export machinery for protein translocation across the cytoplasmic membrane. our results demonstr ...201323163932
high-resolution detection of dna binding sites of the global transcriptional regulator glxr in corynebacterium glutamicum.the transcriptional regulator glxr has been characterized as a global hub within the gene-regulatory network of corynebacterium glutamicum. chromatin immunoprecipitation with a specific anti-glxr antibody and subsequent high-throughput sequencing (chip-seq) was applied to c. glutamicum to get new in vivo insights into the gene composition of the glxr regulon. in a comparative approach, c. glutamicum cells were grown with either glucose or acetate as the sole carbon source prior to immunoprecipit ...201323103979
significance of the cgl1427 gene encoding cytidylate kinase in microaerobic growth of corynebacterium glutamicum.the cgl1427 gene was previously found to be relevant to the microaerobic growth of corynebacterium glutamicum (ikeda et al. biosci biotechnol biochem 73:2806-2808, 2009). in the present work, cgl1427 was identified as a cytidylate kinase gene (cmk) by homology analysis of its deduced amino acid sequence with that of other bacterial cytidylate kinases (cmp kinases) and on the basis of findings that deletion of cgl1427 results in loss of cmp kinase activity. deletion of the cmk gene significantly ...201322810301
next-generation sequencing-based transcriptome analysis of l-lysine-producing corynebacterium glutamicum atcc 21300 strain.in the present study, 151 genes showed a significant change in their expression levels in corynebacterium glutamicum atcc 21300 compared with those of c. glutamicum atcc 13032. of these 151 genes, 56 genes (2%) were up-regulated and 95 genes (3%) were down-regulated. rna sequencing analysis also revealed that 11 genes, involved in the l-lysine biosynthetic pathway of c. glutamicum, were up- or down-regulated compared with those of c. glutamicum atcc 13032. of the 151 genes, 10 genes were identif ...201324385368
microfluidic picoliter bioreactor for microbial single-cell analysis: fabrication, system setup, and operation.in this protocol the fabrication, experimental setup and basic operation of the recently introduced microfluidic picoliter bioreactor (plbr) is described in detail. the plbr can be utilized for the analysis of single bacteria and microcolonies to investigate biotechnological and microbiological related questions concerning, e.g. cell growth, morphology, stress response, and metabolite or protein production on single-cell level. the device features continuous media flow enabling constant environm ...201324336165
enzyme-substrate complexes of the quinate/shikimate dehydrogenase from corynebacterium glutamicum enable new insights in substrate and cofactor binding, specificity, and discrimination.quinate dehydrogenase (qdh) catalyzes the reversible oxidation of quinate to 3-dehydroquinate by nicotineamide adenine dinucleotide (nadh) and is involved in the catabolic quinate metabolism required for the degradation of lignin. the enzyme is a member of the family of shikimate/quinate dehydrogenases (sdh/qdh) occurring in bacteria and plants. we characterized the dual-substrate quinate/shikimate dehydrogenase (qsdh) from corynebacterium glutamicum (cglqsdh) kinetically and revealed a clear su ...201323929881
construction of a prophage-free variant of corynebacterium glutamicum atcc 13032 for use as a platform strain for basic research and industrial biotechnology.the activity of bacteriophages and phage-related mobile elements is a major source for genome rearrangements and genetic instability of their bacterial hosts. the genome of the industrial amino acid producer corynebacterium glutamicum atcc 13032 contains three prophages (cgp1, cgp2, and cgp3) of so far unknown functionality. several phage genes are regularly expressed, and the large prophage cgp3 (∼190 kbp) has recently been shown to be induced under certain stress conditions. here, we present t ...201323892752
development of fatty acid-producing corynebacterium glutamicum strains.to date, no information has been made available on the genetic traits that lead to increased carbon flow into the fatty acid biosynthetic pathway of corynebacterium glutamicum. to develop basic technologies for engineering, we employed an approach that begins by isolating a fatty acid-secreting mutant without depending on mutagenic treatment. this was followed by genome analysis to characterize its genetic background. the selection of spontaneous mutants resistant to the palmitic acid ester surf ...201323995924
visualization of imbalances in sulfur assimilation and synthesis of sulfur-containing amino acids at the single-cell level.we describe genetically encoded sensors which transmit elevated cytosolic concentrations of o-acetyl serine (oas) and o-acetyl homoserine (oah)-intermediates of l-cysteine and l-methionine synthesis-into an optical output. the sensor psenoas3 elicits 7.5-fold-increased fluorescence in cultures of a corynebacterium glutamicum strain that excrete l-cysteine. determination of the cytosolic oas concentration revealed an increase to 0.13 mm, whereas the concentration in the reference strain was below ...201323995919
a structural and dynamic investigation of the inhibition of catalase by nitric oxide.determining the chemical and structural modifications occurring within a protein during fundamental processes such as ligand or substrate binding is essential to building up a complete picture of biological function. currently, significant unanswered questions relate to the way in which protein structural dynamics fit within the structure-function relationship and to the functional role, if any, of bound water molecules in the active site. addressing these questions requires a multidisciplinary ...201324121528
current knowledge on mycolic acids in corynebacterium glutamicum and their relevance for biotechnological processes.corynebacterium glutamicum is the world's largest producer of glutamate and lysine. industrial glutamate overproduction is induced by empirical processes, such as biotin limitation, supplementation with specific surfactants or addition of sublethal concentration of certain antibiotics to the culture media. although gram-positive bacteria, c. glutamicum and related bacterial species and genera contain, in addition to the plasma membrane, an outer permeability membrane similar to that of gram-nega ...201324113823
nmr localization of the o-mycoloylation on porh, a channel forming peptide from corynebacterium glutamicum.porh and pora are two small peptides that, in complex, form a voltage-dependent ion channel in the outer membrane of corynebacterium glutamicum. specific post-translational modifications on pora and porh are required for the formation of a functional ion channel. the assignment of porh proton nmr chemical shifts in dmso, allowed identifying unambiguously the exact position of the porh o-mycoloylation on ser 56 side chain. this was further confirmed by site directed mutagenesis and mass spectrome ...201324100136
functional analysis of tetr-family regulator amtrsav in streptomyces avermitilis.in actinomycetes, two main regulators, the ompr-like glnr and the tetr-type amtr, have been identified as the central regulators for nitrogen metabolism. glnr-mediated regulation was previously identified in different actinomycetes except for members of the genus corynebacterium, in which amtr plays a predominant role in nitrogen metabolism. interestingly, some actinomycetes (e.g. streptomyces avermitilis) harbour both glnr- and amtr-homologous genes in the chromosome. thus, it will be interesti ...201324068239
improvement of cell growth and l-lysine production by genetically modified corynebacterium glutamicum during growth on molasses.fructose-1,6-bisphosphatase (fbpase) and fructokinase (scrk) have important roles in regenerating glucose-6-phosphate in the pentose phosphate pathway (ppp), and thus increasing l-lysine production. this article focuses on the development of l-lysine high-producing strains by heterologous expression of fbpase gene fbp and scrk gene scrk in c. glutamicum lysc (fbr) with molasses as the sole carbon source. heterologous expression of fbp and scrk lead to a decrease of residual sugar in fermentation ...201324029876
impact of different co2/hco3- levels on metabolism and regulation in corynebacterium glutamicum.we investigated the growth kinetics and transcriptional responses of corynebacterium glutamicum in environments with low (pco2<40 mbar) and high (pco2 ≥ 300 mbar) co2/hco3(-) levels compared to standard conditions. when cultivated at high co2/hco3(-)-levels, c. glutamicum showed increased (63%) biomass to substrate yields during the initial growth phase. other kinetic parameters such as growth rate (μ), specific glucose consumption rate (qs), and selected enzymatic activities of anaplerotic reac ...201324140290
elucidation of the regulation of ethanol catabolic genes and ptsg using a glxr and adenylate cyclase gene (cyab) deletion mutants of corynebacterium glutamicum atcc 13032.the cyclic amp receptor protein (crp) homolog, glxr, controls the expression of several genes involved in the regulation of diverse physiological processes in corynebacterium glutamicum. in silico analysis has revealed the presence of glxr binding sites upstream of genes adha, ald, and ptsg, encoding glucose-specific phosphotransferase system protein, alcohol dehydrogenase (adh), and acetaldehyde dehydrogenase (aldh), respectively. however, the involvement of the glxr-camp complex on the express ...201324150494
lysine overproducing corynebacterium glutamicum is characterized by a robust linear combination of two optimal phenotypic states.a homoserine auxotroph strain of corynebacterium glutamicum accumulates storage compound trehalose with lysine when limited by growth. industrially lysine is produced from c. glutamicum through aspartate biosynthetic pathway, where enzymatic activity of aspartate kinase is allosterically controlled by the concerted feedback inhibition of threonine plus lysine. ample threonine in the medium supports growth and inhibits lysine production (phenotype-i) and its complete absence leads to inhibition o ...201324432142
c1 metabolism in corynebacterium glutamicum: an endogenous pathway for oxidation of methanol to carbon dioxide.methanol is considered an interesting carbon source in "bio-based" microbial production processes. since corynebacterium glutamicum is an important host in industrial biotechnology, in particular for amino acid production, we performed studies of the response of this organism to methanol. the c. glutamicum wild type was able to convert (13)c-labeled methanol to (13)co2. analysis of global gene expression in the presence of methanol revealed several genes of ethanol catabolism to be upregulated, ...201324014532
directed evolution and structural analysis of nadph-dependent acetoacetyl-coa reductase from ralstonia eutropha reveals two mutations responsible for enhanced kinetics.nicotinamide adenine dinucleotide phosphate (nadph)-dependent acetoacetyl-coa reductase (phab) is a key enzyme in the synthesis of poly(3-hydroxybutyrate) [p(3hb)], along with β-ketothiolase (phaa) and polyhydroxyalkanoate synthase (phac). in this study, phab from ralstonia eutropha was engineered by means of directed evolution consisting of an error-prone pcr-mediated mutagenesis and a p(3hb) accumulation-based in vivo screening system using escherichia coli. out of approximately twenty thousan ...201323913421
recognition of microbial and mammalian phospholipid antigens by nkt cells with diverse tcrs.cd1d-restricted natural killer t (nkt) cells include two major subgroups. the most widely studied are vα14jα18(+) invariant nkt (inkt) cells that recognize the prototypical α-galactosylceramide antigen, whereas the other major group uses diverse t-cell receptor (tcr) α-and β-chains, does not recognize α-galactosylceramide, and is referred to as diverse nkt (dnkt) cells. dnkt cells play important roles during infection and autoimmunity, but the antigens they recognize remain poorly understood. he ...201323307809
ornithine cyclodeaminase-based proline production by corynebacterium glutamicum.the soil bacterium corynebacterium glutamicum, best known for its glutamate producing ability, is suitable as a producer of a variety of bioproducts. glutamate is the precursor of the amino acid proline. proline biosynthesis typically involves three enzymes and a spontaneous cyclisation reaction. alternatively, proline can be synthesised from ornithine, an intermediate of arginine biosynthesis. the direct conversion of ornithine to proline is catalysed by ornithine cyclodeaminase. an ornithine o ...201323806148
inactivation of the phosphoglucomutase gene pgm in corynebacterium glutamicum affects cell shape and glycogen metabolism.in corynebacterium glutamicum formation of glc-1-p (α-glucose-1-phosphate) from glc-6-p (glucose-6-phosphate) by α-pgm (phosphoglucomutase) is supposed to be crucial for synthesis of glycogen and the cell wall precursors trehalose and rhamnose. furthermore, pgm is probably necessary for glycogen degradation and maltose utilization as glucan phosphorylases of both pathways form glc-1-p. we here show that c. glutamicum possesses at least two pgm isoenzymes, the cg2800 (pgm) encoded enzyme contribu ...201323863124
a novel type of n-acetylglutamate synthase is involved in the first step of arginine biosynthesis in corynebacterium glutamicum.arginine biosynthesis in corynebacterium glutamicum consists of eight enzymatic steps, starting with acetylation of glutamate, catalysed by n-acetylglutamate synthase (nags). there are different kinds of known nagss, for example, "classical" arga, bifunctional argj, argo, and s-nags. however, since c. glutamicum possesses a monofunctional argj, which catalyses only the fifth step of the arginine biosynthesis pathway, glutamate must be acetylated by an as of yet unknown nags gene.201324138314
expression, crystallization and preliminary crystallographic study of glub from corynebacterium glutamicum.glub is a substrate-binding protein (sbp) which participates in the uptake of glutamic acid in corynebacterium glutamicum, a gram-positive bacterium. it is part of an atp-binding cassette (abc) transporter system. together with the transmembrane proteins gluc and glud and the cytoplasmic protein glua, which couples the hydrolysis of atp to the translocation of glutamate, they form a highly active glutamate-uptake system. as part of efforts to study the amino-acid metabolism, especially the metab ...201323722846
asymmetric chromosome segregation in xanthomonas citri ssp. citri.this study was intended to characterize the chromosome segregation process of xanthomonas citri ssp. citri (xac) by investigating the functionality of the parb factor encoded on its chromosome, and its requirement for cell viability and virulence. using tap tagging we show that parb is expressed in xac. disruption of parb increased the cell doubling time and precluded the ability of xac to colonize the host citrus. moreover, xac mutant cells expressing only truncated forms of parb exhibited the ...201324339434
crystallization and preliminary x-ray crystallographic analysis of the amylomaltase from corynebacterium glutamicum.amylomaltase (am; ec 2.4.1.25) belongs to the 4-α-glucanotransferase group of the α-amylase family. the enzyme can produce cycloamylose or large-ring cyclodextrin through intramolecular transglycosylation or cyclization reactions of α-1,4-glucan. amylomaltase from the mesophilic bacterium corynebacterium glutamicum (cgam) contains extra residues at the n-terminus for which the three-dimensional structure is not yet known. in this study, cgam was overexpressed and purified to homogeneity using de ...201323989149
comprehensive analysis of the corynebacterium glutamicum transcriptome using an improved rnaseq technique.the use of rnaseq to resolve the transcriptional organization of an organism was established in recent years and also showed the complexity and dynamics of bacterial transcriptomes. the aim of this study was to comprehensively investigate the transcriptome of the industrially relevant amino acid producer and model organism corynebacterium glutamicum by rnaseq in order to improve its genome annotation and to describe important features for transcription and translation.201324341750
modulation of global low-frequency motions underlies allosteric regulation: demonstration in crp/fnr family transcription factors.allostery is a fundamental process by which ligand binding to a protein alters its activity at a distinct site. there is growing evidence that allosteric cooperativity can be communicated by modulation of protein dynamics without conformational change. the mechanisms, however, for communicating dynamic fluctuations between sites are debated. we provide a foundational theory for how allostery can occur as a function of low-frequency dynamics without a change in structure. we have generated coarse ...201324058293
complex regulation of the phosphoenolpyruvate carboxykinase gene pck and characterization of its gntr-type regulator iolr as a repressor of myo-inositol utilization genes in corynebacterium glutamicum.dna affinity chromatography with the promoter region of the corynebacterium glutamicum pck gene, encoding phosphoenolpyruvate carboxykinase, led to the isolation of four transcriptional regulators, i.e., rama, gntr1, gntr2, and iolr. determination of the phosphoenolpyruvate carboxykinase activity of the δrama, δgntr1 δgntr2, and δiolr deletion mutants indicated that rama represses pck during growth on glucose about 2-fold, whereas gntr1, gntr2, and iolr activate pck expression about 2-fold irres ...201323873914
Refresh
firstprev
12345678910...
nextlast
Displaying items 501 - 600 of 2194