orabase and lichenin

Topics: Archaea; beta-Glucans; Bioreactors; Carboxymethylcellulose Sodium; Cellulase; Galactans; Glucans; Hordeum; Hot Temperature; Hydrothermal Vents; Islands; Mannans; Mediterranean Region; Metagenome; Plant Gums

Glycoside hydrolase family 8 (GH8) includes endoglucanases, lichenases, chitosanases and xylanases, which are essential for polysaccharides breakdown. In this work, we studied a thermally stable GH8 from the cellulose synthase complex of Enterobacter sp. R1, for deconstruction of β-glucans. The biochemical characterization of the recombinant GH8ErCel showed high specificity towards barley β-glucan and lichenan and lower activity on carboxymethylcellulose and swollen cellulose, yielding different length oligosaccharides. By molecular modeling, six conserved subsites for glucose binding and some possible determinants for its lack of xylanase and chitosanase activity were identified. GH8ErCel was active at a broad range of pH and temperature and presented remarkable stability at 60 °C. Additionally, it hydrolyzed β-glucan from oat and wheat brans mainly to tri- and tetraoligosaccharides. Therefore, GH8ErCel may be a good candidate for enzymatic deconstruction of β-glucans at high temperature in food and feed industries, including the production of prebiotics and functional foods.

Topics: Argentina; beta-Glucans; Carboxymethylcellulose Sodium; Cellulase; Cellulose; Enterobacter; Enzyme Stability; Glucans; Glucose; Hydrogen-Ion Concentration; Hydrolysis; Oligosaccharides; Recombinant Proteins; Soil Microbiology; Substrate Specificity; Temperature

An extracellular 1,3-1,4-β-glucanase-producing strain S2 was isolated from booklice and identified as Bacillus methylotrophicus. Furthermore, a homogeneous extracellular 1,3-1,4-β-glucanase GCS2 was purified by ammonium sulfate precipitation and cation-exchange chromatography. The gene for the 1,3-1,4-β-glucanase was cloned, and the nucleotide sequence was determined. Characterization of the purified enzyme revealed the molecular mass of 26 kDa and the optimum activity at pH 7.5, 55°C. The purified enzyme can highly hydrolyze carboxymethylcellulose including oat gum, barley β-glucan, CMC and lichenan, while low activity on avicel, cellobiose, filter paper, p-nitrophenyl β-d-cellobioside, and p-nitrophenyl β-d-glucoside, but no activity against microcrystalline cellulose or salicin. The enzyme was stable at wide range of pHs 5-10 and still maintained above 60% activity at 70°C. The enzyme activity was stimulated by Trixon X-100. The property of the enzyme GCS2 makes this enzyme a broad prospect in brewing and commercial detergent industry. To our knowledge, this is the first report of a 1,3-1,4-β-glucanase from microbes associated with booklice.

Topics: Animals; Bacillus; beta-Glucosidase; Carboxymethylcellulose Sodium; Cellobiose; Cellulose; Chromatography, Ion Exchange; Cloning, Molecular; Glucans; Glucosides; Hydrogen-Ion Concentration; Hydrolysis; Molecular Weight; Phthiraptera; Sequence Analysis, DNA; Substrate Specificity; Temperature

A novel endoglucanase encoding gene was cloned from Alicyclobacillus vulcanalis and expressed in E. coli. The deduced amino acid sequence showed highest identity with α-L-arabinofuranosidase-like proteins from glycoside hydrolase family 51. The recombinant enzyme was purified by affinity chromatography and characterised in terms of its potential suitability for lignocellulose hydrolysis at high temperature in the production of bioethanol. The purified enzyme displayed maximum activity at 80 °C and pH 3.6-4.5. Tween 20 was found to have a beneficial effect on enzyme activity and thermal stability. When incubated in the presence of 0.1% Tween 20, the enzyme retained full activity after 72 h at 70 °C and 78% of original activity after 72 h at 75 °C. Maximum activity was observed on carboxymethyl cellulose, and the purified enzyme also hydrolysed lichenan, barley β-glucan and xylan. The purified enzyme decreased the viscosity of carboxymethyl cellulose when assessed at 70-85 °C and was capable of releasing reducing sugars from acid-pretreated straw at 70 and 75 °C. The results indicate the potential suitability of the enzyme for industrial application in the production of cellulosic bioethanol.

Topics: Alicyclobacillus; beta-Glucans; Biofuels; Carboxymethylcellulose Sodium; Cellulase; Chromatography, Affinity; Cloning, Molecular; Enzyme Activators; Enzyme Stability; Escherichia coli; Ethanol; Glucans; Hot Temperature; Hydrogen-Ion Concentration; Hydrolysis; Plant Stems; Polysorbates; Recombinant Proteins; Substrate Specificity; Xylans

Three isozymes with both lichenase and endo-β-1,4-glucanase activity were purified and characterised from the midgut gland of the herbivorous gecarcinid land crab, Gecarcoidea natalis. The three isozymes, termed 1a, 1b and 2, had respective molecular masses of 53 ± 0 (3), 43 ± 0 (3) and 47.4 ± 0(3) kDa. All isozymes possessed similar V(max) values and thus hydrolysed both carboxy methyl cellulose and lichenan equally. Furthermore the chromatography profiles for lichenase activities mirrored that for endo-β-1,4-glucanase activities suggesting that the same enzyme possessed both activities. Given this, the endo-β-1,4-glucanase enzymes described for other animals, may, like the isozymes described in this study, may be able to hydrolyse lichenan. However this ability needs to be confirmed. The main digestive function of these isozymes may be to hydrolyse hemicelluloses such as lichenan and mixed beta-D-glucan. All three isozymes randomly hydrolysed internal glycosidic bonds within carboxy methyl cellulose and lichenan to release short oligomers of 4-5 glucose units in length. They also hydrolysed cellotetraose to either two units of cellobiose or cellotriose and glucose. Cellotriose was hydrolysed to cellobiose and glucose. All three enzymes lacked β-1,4-glucosidase activity as they could not hydrolyse cellobiose.

Topics: Adaptation, Biological; Animals; Brachyura; Carboxymethylcellulose Sodium; Cellulase; Cellulose; Glucans; Glycoside Hydrolases; Hydrogen-Ion Concentration; Isoenzymes; Substrate Specificity; Tetroses

A gene encoding a glycoside hydrolase family 44 (GH44) protein from Clostridium acetobutylicum ATCC 824 was synthesized and transformed into Escherichia coli. The previously uncharacterized protein was expressed with a C-terminal His tag and purified by nickel-nitrilotriacetic acid affinity chromatography. Crystallization and X-ray diffraction to a 2.2-A resolution revealed a triose phosphate isomerase (TIM) barrel-like structure with additional Greek key and beta-sandwich folds, similar to other GH44 crystal structures. The enzyme hydrolyzes cellotetraose and larger cellooligosaccharides, yielding an unbalanced product distribution, including some glucose. It attacks carboxymethylcellulose and xylan at approximately the same rates. Its activity on carboxymethylcellulose is much higher than that of the isolated C. acetobutylicum cellulosome. It also extensively converts lichenan to oligosaccharides of intermediate size and attacks Avicel to a limited extent. The enzyme has an optimal temperature in a 10-min assay of 55 degrees C and an optimal pH of 5.0.

Topics: Carboxymethylcellulose Sodium; Cellulase; Cellulose; Clostridium acetobutylicum; Crystallization; Crystallography, X-Ray; Enzyme Stability; Escherichia coli; Gene Expression; Glucans; Glucose; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Oligosaccharides; Phylogeny; Protein Structure, Tertiary; Recombinant Proteins; Sequence Homology, Amino Acid; Substrate Specificity; Temperature; Tetroses; Transformation, Genetic; Xylans

In this paper, we present the first detailed analysis of the modes of action of three purified, thermostable endo-beta-D-glucanases (EG V-VII) against a range of soluble beta-linked glucans. Studies indicated that EG V-VII, purified to homogeneity from a new source, the thermophilic fungus Talaromyces emersonii, are strict beta-glucanases that exhibit maximum activity against mixed-link 1,3;1,4-beta-D-glucans. Time-course hydrolysis studies of 1,4-beta-D-glucan (carboxymethylcellulose; CMC), 1,3;1,4-beta-D-glucan from barley (BBG) and lichenan confirmed the endo-acting nature of EG V-VII and verified preference for 1,3;1,4-beta-D-glucan substrates. The results suggest that EG VI and EG VII belong to EC 3.2.1.6, as both enzymes also exhibit activity against 1,3-beta-glucan (laminaran), in contrast to EG V. Although cellobiose, cellotriose and glucose were the main glucooligosaccharide products released, the range and relative amount of each product was dependent on the particular enzyme, substrate and reaction time. Kinetic constants (Km, Vmax, kcat and kcat/Km) determined for EG V-VII with BBG as substrate yielded similar Km and Vmax values for EG V and EG VI. EG VII exhibited highest affinity for BBG (Km value of 9.1 mg ml(-1)) and the highest catalytic efficiency (kcat/Km of 12.63 s(-1) mg(-1) ml).

Topics: Carbohydrate Conformation; Carboxymethylcellulose Sodium; Catalysis; Cellulase; Chromatography, Ion Exchange; Glucans; Glycoside Hydrolases; Hordeum; Kinetics; Polysaccharides; Solubility; Substrate Specificity; Talaromyces; Viscosity

A major extracellular endoglucanase purified to homogeneity from Thermoascus aurantiacus had a M(r) of 34 kDa and a pI of 3.7 and was optimally active at 70-80 degrees C and pH 4.0-4.4. It was stable at pH 2.8-6.8 at 50 degrees C for 48 h and maintained its secondary structure and folded conformation up to 70 degrees C at pH 5.0 and 2.8, respectively. A 33-amino acid sequence at the N terminus showed considerable homology with 14 microbial endoglucanases having highly conserved 8 amino acids (positions 10-17) and Gly, Pro, Gly, and Pro at positions 8, 22, 23, and 32, respectively. The enzyme is rich in Asp (15%) and Glu (10%) with a carbohydrate content of 2.7%. Polyclonal antibodies of endoglucanase cross-reacted with their own antigen and with other purified cellulases from T. aurantiacus. The endoglucanase was specific for polymeric substrates with highest activity toward carboxymethyl cellulose followed by barley beta-glucan and lichenan. It preferentially cleaved the internal glycosidic bonds of Glc(n) and MeUmbGlc(n) and possessed an extended substrate-binding site with five subsites. The data indicate that the endoglucanase from T. aurantiacus is a member of glycoside hydrolase family 5.

Topics: Ascomycota; Calorimetry, Differential Scanning; Carboxymethylcellulose Sodium; Cellulase; Chromatography, High Pressure Liquid; Enzyme Activation; Enzyme Stability; Extracellular Space; Glucans; Hydrogen-Ion Concentration; Molecular Sequence Data; Protein Conformation; Protein Folding; Protein Structure, Secondary; Sequence Analysis, Protein; Sequence Homology, Amino Acid; Substrate Specificity; Temperature; Thermodynamics

A cellulase from the ruminal fungus Orpinomyces joyonii cloned in Escherichia coli was purified 88-fold by chromatography on High Q and hydroxyapatite. N-terminal amino acid sequence analyses confirmed that the cellulase represented the product of the cellulase gene Cel B2. The purified enzyme possessed high activity toward barley beta-glucan, lichenan, carboxymethyl cellulose (CMC), xylan, but not toward laminarin and pachyman. In addition, the cloned enzyme was able to hydrolyze p-nitrophenyl (PNP)-cellobioside, PNP-cellotrioside, PNP-cellotetraoside, PNP-cellopentaoside, but not PNP-glucopyranoside. The specific activity of the cloned enzyme on barley beta-glucan was 297 units/mg protein. The purified enzyme appeared as a single band in SDS-polyacrylamide gel electrophoresis and the molecular mass of this enzyme (58000) was consistent with the value (56463) calculated from the DNA sequence. The optimal pH of the enzyme was 5.5, and the enzyme was stable between pH 5.0 and pH 7.5. The enzyme had a temperature optimum at 40 degrees C. The K(m) values estimated for barley beta-glucan and CMC were 0.32 and 0.50 mg/ml, respectively.

Topics: Carboxymethylcellulose Sodium; Cellulase; Chromatography; Chromatography, Gel; Cloning, Molecular; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Glucans; Hydrogen-Ion Concentration; Neocallimastigales; Temperature; Xylans

The main properties (pH and temperature range, stability, substrate specificity) of the modified cellulase CelE (endo-beta-1,4-glucanase) from Clostridium thermocellum have been analyzed with the goal of its expression in plants. The modified enzyme is similar to plant cellulases. Deletions in the N-terminus of the enzyme do not affect its biochemical properties. Based on the present investigation, we conclude that the modified beta-1,4-glucanase CelEM1, when expressed in plants, will be a good model to study the role of cellulases in plants.

Topics: Bacterial Proteins; Carboxymethylcellulose Sodium; Cellulase; Clostridium; Computer Simulation; Enzyme Activation; Gene Expression; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Plant; Glucans; Models, Genetic; Mutation; Plants; Sequence Deletion

A cellulase gene (endA) was isolated from a library of Ruminococcus flavefaciens strain 17 DNA fragments inserted in pUC13. The endA product showed activity against acid-swollen cellulose, carboxymethyl-cellulose, lichenan, cellopentaose and cellotetraose, but showed no activity against cellotriose or binding to avicel. Nucleotide sequencing indicated an encoded product of 455 amino acids which showed significant sequence similarity (ranging from 56% to 61%) with three endoglucanases from Ruminococcus albus, and with Clostridium thermocellum endoglucanase E. Little relatedness was found with a cellodextrinase previously isolated from R. flavefaciens FD1.

Topics: Amino Acid Sequence; Base Sequence; Carboxymethylcellulose Sodium; Cellulase; Cellulose; Cloning, Molecular; Genes, Bacterial; Glucans; Molecular Sequence Data; Oligosaccharides; Restriction Mapping; Sequence Homology, Nucleic Acid; Substrate Specificity; Tetroses; Transformation, Bacterial; Trisaccharides

An endoglucanase gene, engB, from Clostridium cellulovorans, previously cloned into pUC19, has been further characterized and its product investigated. The enzyme, EngB, encoded by the gene was secreted into the periplasmic space of Escherichia coli. The enzyme was active against carboxymethylcellulose, xylan and lichenan but not Avicel (crystalline cellulose). The sequenced gene showed an open reading frame of 1323 base pairs and coded for a protein with a molecular mass of 48.6 kDa. The mRNA contained a typical Gram-positive ribosome-binding site sequence GGAGG and a sequence coding for a putative signal peptide. There is high amino acid and base sequence homology between the N-terminal regions of EngB and another C. cellulovorans endoglucanase, EngD, but they differ significantly in their C-termini. Deletion analyses revealed that up to 32 amino acids of the N-terminus and 52 amino acids of the C-terminus were not required for catalytic activity. The conserved reiterated domains at the C-terminus of EngB were similar to those from endoglucanases from other cellulytic bacteria. According to our deletion analyses, this region is not needed for catalytic activity.

Topics: Amino Acid Sequence; Base Sequence; Carboxymethylcellulose Sodium; Cellulase; Cloning, Molecular; Clostridium; DNA Mutational Analysis; Escherichia coli; Glucans; Molecular Sequence Data; Open Reading Frames; Sequence Homology, Nucleic Acid; Xylans

A cel gene from Bacteroides succinogenes inserted into the vector pUC8 coded for an enzyme which exhibited high hydrolytic activity on carboxymethylcellulose, p-nitrophenylcellobioside, and lichenan and low activity on laminarin and xylan. The enzyme was not synthesized by the Escherichia coli host when cells were cultured in complex medium containing added glucose. In the absence of added glucose, the endoglucanase and cellobiosidase activities synthesized were partitioned into the periplasmic space during growth, and practically all enzyme was located in the periplasm when the stationary phase of growth was reached. The enzyme exhibited 17- and sixfold higher Km values for the hydrolysis of carboxymethylcellulose and lichenan, respectively, than did the extracellular endoglucanase complex from B. succinogenes. The Cel endoglucanase had a pH optimum similar to that of the B. succinogenes enzyme except that the range was narrower, and the Cel endoglucanase was more readily inactivated on exposure to high temperature, detergents, and certain metals. Its activity was stimulated by calcium and magnesium. Nondenaturing polyacrylamide gel electrophoresis at different acrylamide concentrations revealed the presence of three endoglucanase components, two with molecular weights of 43,000 and one with a molecular weight of 55,000.

Topics: Bacteroides; Carboxymethylcellulose Sodium; Cellulase; Cellulose; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Genes, Bacterial; Glucans; Glucosides; Hydrogen-Ion Concentration; Molecular Weight; Polysaccharides; Xylans

Comparative investigations were carried out concerning substrate specificity and action patterns of seven Bacillus-endo-beta-glucanases produced by the species, B. subtilis, B. macerans, B. amyloliquefaciens, B. circulans, B. laterosporus, B. pumilus and B. polymyxa. All enzymes with the exception of beta-glucanase from B. macerans hydrolyze lichenan and barley-beta-glucan only and were without action on laminaran and CM-cellulose. It was suggested that hydrolysis products of beta-glucanase produced by B. macerans were markedly different from the products of the other enzymes. We conclude that B. macerans enzyme, which cleaves laminaran and beta-1,3-1,4-glucans, represents "laminarinase" type (1-3-beta-D-glucan glucanohydrolase, E.C. 3.2.1.6). On the other hand the glucanases produced by the other Bacillus strains belong to "licheninases" 1-3,1-4-beta-D-glucan glucanohydrolases, E.C. 3.2.1.73).

Topics: Bacillus; Bacillus subtilis; Carboxymethylcellulose Sodium; Glucans; Glycoside Hydrolases; Polysaccharides; Substrate Specificity