- MeSH
- biomedicínský výzkum trendy MeSH
- biotechnologie trendy MeSH
- kongresy jako téma MeSH
- mezinárodní spolupráce * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
- Slovenská republika MeSH
- východní Evropa MeSH
The rapid accumulation of sequence data and powerful protein engineering techniques providing large mutant libraries have greatly heightened interest in efficient methods for biochemical characterization of proteins. Herein is reported a continuous assay for screening of enzymatic activity. The assay is developed and tested with the model enzymes haloalkane dehalogenases and relies upon a fluorescent change of a derivative of 8-hydroxypyrene-1,3,6-trisulphonic acid due to the pH drop associated with the dehalogenation reactions. The assay is performed in a microplate format using a purified enzyme, cell-free extract or intact cells, making the analysis quick and simple. The method exhibits high sensitivity with a limit of detection of 0.06 mM. The assay is successfully validated with gas chromatography and then applied for screening of 12 haloalkane dehalogenases with the environmental pollutant bis(2-chloroethyl) ether and chemical warfare agent sulfur mustard. Six enzymes exhibited detectable activity with both substrates. The within-day variability of the assay for five replicates (n = 5) was 21%.
The peptide LL-37, a component of the human innate immune system, represents a promising drug candidate. In particular, the development of low-cost production platform technology is a critical bottleneck in its use in medicine. In the present study, a viable approach for the LL-37 production in transgenic barley is developed. First, comparative analyses of the effects of different fused peptide epitope tags applicable for accumulation and purification on LL-37 production yield are performed using transient expression in tobacco leaves. Following the selection of the most yielding fusion peptide strategies, eight different constructs for the expression of codon optimized chimeric LL-37 genes in transgenic barley plants are created. The expression of individual constructs is driven either by an endosperm-specific promoter of the barley B1 hordein gene or by the maize ubiquitin promoter. The transgenes are stably integrated into the barley genome and inherited in the subsequent generation. All transgenic lines show normal phenotypes and are fertile. LL-37 accumulated in the barley seeds up to 0.55 mg per 1 kg of grain. The fused epitope tags are cleaved off by the use of enterokinase. Furthermore, in planta produced LL-37 including the fused versions is biologically active.
- MeSH
- geneticky modifikované rostliny genetika metabolismus MeSH
- ječmen (rod) genetika metabolismus MeSH
- kathelicidiny chemie genetika izolace a purifikace metabolismus MeSH
- lidé MeSH
- molekulární farmaření metody MeSH
- promotorové oblasti (genetika) genetika MeSH
- rekombinantní fúzní proteiny chemie genetika izolace a purifikace metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Controlled feeding of glucose has been employed previously to enhance the productivity of recombinant glycoproteins but there is a concern that low concentrations of glucose could limit the synthesis of precursors of glycosylation. Here we investigate the effect of glucose depletion on the metabolism, productivity and glycosylation of a chimeric human-llama monoclonal antibody secreted by CHO cells. The cells were inoculated into media containing varying concentrations of glucose. Glucose depletion occurred in cultures with an initial glucose ≤5.5 mM and seeded at low density (2.5 × 10(5) cells/mL) or at high cell inoculum (≥2.5 × 10(6) cells/mL) at higher glucose concentration (up to 25 mM). Glucose-depleted cultures produced non-glycosylated Mabs (up to 51%), lower galactosylation index (GI <0.43) and decreased sialylation (by 85%) as measured by mass spectrometry and HPLC. At low glucose a reduced intracellular pool of nucleotides (0.03-0.23 fmoles/cell) was measured as well as a low adenylate energy charge (<0.57). Low glucose also reduced GDP-sugars (by 77%) and UDP-hexosamines (by 90%). The data indicate that under glucose deprivation, low levels of intracellular nucleotides and nucleotide sugars reduced the availability of the immediate precursors of glycosylation. These results are important when applied to the design of fed-batch cultures.
- MeSH
- CHO buňky MeSH
- Cricetulus MeSH
- glukosa metabolismus MeSH
- glykoproteiny biosyntéza metabolismus MeSH
- glykosylace MeSH
- křečci praví MeSH
- lidé MeSH
- monoklonální protilátky biosyntéza metabolismus MeSH
- rekombinantní proteiny biosyntéza genetika MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Enzymes have a wide range of applications in different industries owing to their high specificity and efficiency. Immobilization is often used to improve biocatalyst properties, operational stability, and reusability. However, changes in the structure of biocatalysts during immobilization and under process conditions are still largely uncertain. Here, three microscopy techniques - bright-field, confocal and electron microscopy - were applied to determine the distribution and structure of an immobilized biocatalyst. Free enzyme (haloalkane dehalogenase), cross-linked enzyme aggregates (CLEAs) and CLEAs entrapped in polyvinyl alcohol lenses (lentikats) were used as model systems. Electron microscopy revealed that sonicated CLEAs underwent morphological changes that strongly correlated with increased catalytic activity compared to less structured, non-treated CLEAs. Confocal microscopy confirmed that loading of the biocatalyst was not the only factor affecting the catalytic activity of the lentikats. Confocal microscopy also showed a significant reduction in the pore size of lentikats exposed to 25% tetrahydrofuran and 50% dioxane. Narrow pores appeared to provide protection to CLEAs from the detrimental action of cosolvents, which significantly correlated with higher activity of CLEAs compared to free enzyme. The results showed that microscopy can provide valuable information about the structure and properties of a biocatalyst during immobilization and under process conditions.
- MeSH
- biokatalýza MeSH
- dioxany farmakologie MeSH
- furany farmakologie MeSH
- hydrolasy chemie metabolismus MeSH
- mikroskopie metody MeSH
- proteiny červů chemie metabolismus MeSH
- Schistosoma japonicum enzymologie MeSH
- stabilita enzymů MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Haloalkane dehalogenases (EC 3.8.1.5, HLDs) are α/β-hydrolases which act to cleave carbon-halogen bonds. Due to their unique catalytic mechanism, broad substrate specificity and high robustness, the members of this enzyme family have been employed in several practical applications: (i) biocatalytic preparation of optically pure building-blocks for organic synthesis; (ii) recycling of by-products from chemical processes; (iii) bioremediation of toxic environmental pollutants; (iv) decontamination of warfare agents; (v) biosensing of environmental pollutants; and (vi) protein tagging for cell imaging and protein analysis. This review discusses the application of HLDs in the context of the biochemical properties of individual enzymes. Further extension of HLD uses within the field of biotechnology will require currently limiting factors - such as low expression, product inhibition, insufficient enzyme selectivity, low affinity and catalytic efficiency towards selected substrates, and instability in the presence of organic co-solvents - to be overcome. We propose that strategies based on protein engineering and isolation of novel HLDs from extremophilic microorganisms may offer solutions.
Haloalkane dehalogenases are microbial enzymes with a wide range of biotechnological applications, including biocatalysis. The use of organic co-solvents to solubilize their hydrophobic substrates is often necessary. In order to choose the most compatible co-solvent, the effects of 14 co-solvents on activity, stability and enantioselectivity of three model enzymes, DbjA, DhaA, and LinB, were evaluated. All co-solvents caused at high concentration loss of activity and conformational changes. The highest inactivation was induced by tetrahydrofuran, while more hydrophilic co-solvents, such as ethylene glycol and dimethyl sulfoxide, were better tolerated. The effects of co-solvents at low concentration were different for each enzyme-solvent pair. An increase in DbjA activity was induced by the majority of organic co-solvents tested, while activities of DhaA and LinB decreased at comparable concentrations of the same co-solvent. Moreover, a high increase of DbjA enantioselectivity was observed. Ethylene glycol and 1,4-dioxane were shown to have the most positive impact on the enantioselectivity. The favorable influence of these co-solvents on both activity and enantioselectivity makes DbjA suitable for biocatalytic applications. This study represents the first investigation of the effects of organic co-solvents on the biocatalytic performance of haloalkane dehalogenases and will pave the way for their broader use in industrial processes.
- MeSH
- bakteriální proteiny chemie metabolismus MeSH
- cirkulární dichroismus MeSH
- furany MeSH
- hydrolasy chemie metabolismus MeSH
- organické látky chemie MeSH
- rekombinantní fúzní proteiny chemie metabolismus MeSH
- rozpouštědla chemie MeSH
- stabilita enzymů MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The knowledge of the access paths connecting interior of molecular systems with surrounding environment is important for the understanding of structurefunction relationships and engineering of molecules for biotechnological applications. CAVER is a computer program developed for calculations of tunnels, channels or pores in the biomolecules, inorganic materials and molecular ensembles. The algorithm performs a skeleton search based on a reciprocal distance function grid. The algorithm is implemented in the stand-alone version, web version and as plug-in for PyMol. CAVER is available from the website http://loschmidt.chemi.muni.cz/caver
- MeSH
- algoritmy MeSH
- anorganické látky chemie MeSH
- chemické modely MeSH
- financování organizované MeSH
- makromolekulární látky chemie MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- nukleové kyseliny chemie ultrastruktura MeSH
- počítačová grafika MeSH
- počítačová simulace MeSH
- proteiny chemie ultrastruktura MeSH
- software MeSH
- uživatelské rozhraní počítače MeSH
Easily available commercial enzymes currently have great potential in bast fibre processing and can be modified for different end uses. There are several new technologies using enzymes that are able to modify fibre parameters, achieve requested properties, improve processing results and are more beneficial to the ecology in the area of bast fibre processing and fabrics finishing. Enzymatic methods for retting of flax, "cottonisation" of bast fibres, hemp separation, and processing of flax rovings before wet spinning, etc., fall into this group of new technologies. Such enzymatic biotechnologies can provide benefits in textile, composite, reinforced plastic and other technical applications. Laboratory, pilot and industrial scale results and experiences have demonstrated the ability of selected enzymes to decompose interfibre-bonding layers based on pectin, lignin and hemicelluloses. Texazym SER spray is able to increase flax long fibre yields by more than 40%. Other enzymes in combination with mild mechanical treatment can replace aggressive and energy-intensive processing like Laroche "cottonisation". Texazym SCW and DLG pretreatments of flax rovings are presented.
