Structural basis for branching-enzyme activity of glycoside hydrolase family 57: Structure and stability studies of a novel branching enzyme from the hyperthermophilic archaeon Thermococcus Kodakaraensis KOD1

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Deciphering the synergism of endogenous glycoside hydrolase families 1 and 9 from Coptotermes gestroi

Termites can degrade up to 90% of the lignocellulose they ingest using a repertoire of endogenous and symbiotic degrading enzymes. Termites have been shown to secrete two main glycoside hydrolases, which are GH1 (EC 3.2.1.21) and GH9 (EC 3.2.1.4) members. However, the molecular mechanism for lignocellulose degradation by these enzymes remains poorly understood. The present study was conducted to understand the synergistic relationship between GH9 (CgEG1) and GH1 (CgBG1) from Coptotermes gestroi, which is considered the major urban pest of São Paulo State in Brazil. The goal of this work was to decipher the mode of operation of CgEG1 and CgBG1 through a comprehensive biochemical analysis and molecular docking studies. There was outstanding degree of synergy in degrading glucose polymers for the production of glucose as a result of the endo-β-1,4-glucosidase and exo-β-1,4-glucosidase degradation capability of CgEG1 in concert with the high catalytic performance of CgBG1, which rapidly converts the oligomers into glucose. Our data not only provide an increased comprehension regarding the synergistic mechanism of these two enzymes for cellulose saccharification but also give insight about the role of these two enzymes in termite biology, which can provide the foundation for the development of a number of important applied research topics, such as the control of termites as pests as well as the development of technologies for lignocellulose-to-bioproduct applications. © 2013 Elsevier Ltd.

Aspergillus niger beta-Glucosidase Has a Cellulase-like Tadpole Molecular Shape INSIGHTS INTO GLYCOSIDE HYDROLASE FAMILY 3 (GH3) beta-GLUCOSIDASE STRUCTURE AND FUNCTION

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Understanding the Function of Conserved Variations in the Catalytic Loops of Fungal Glycoside Hydrolase Family 12

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conformational changes in a hyperthermostable glycoside hydrolase: enzymatic activity is a consequence of the loop dynamics and protonation balance

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dependence of divalent metal ions on phosphotransferase activity of osseous plate alkaline phosphatase

Kinetic evidence for the role of divalent metal ions in the phosphotransferase activity of polidocanol-solubilized alkaline phosphatase from osseous plate is reported. Ethylenediamine tetreacetate, 1,10-phenanthrolin, and Chelex-100 were used to prepare metal-depleted alkaline phosphatase. Except for Chelex-100, either irreversible inactivation of the enzyme or incomplete removal of metal ions occurred. After Chelex-100 treatment, full hydrolase activity of alkaline phosphatase was recovered upon addition of metal ions. on the other hand, only 20% of transferase activity was restored with 0.1 mu M ZnCl2, in the presence of 1.0 M diethanolamine as phosphate acceptor. In the presence of 0.1 mM MgCl2, the recovery of transferase activity increased to 63%. Independently of the phosphate acceptor used, the transferase activity of the metal-depleted alkaline phosphatase was fully restored by 8 mu M ZnCl2 plus 5 mM MgCl2. In the presence of diethanolamine as phosphate acceptor, manganese, cobalt, and calcium ions did nor stimulate the transferase activity. However, manganese and cobalt-enzyme catalyzed the transfer of phosphate to glycerol and glucose. (C) 1997 Elsevier B.V.

cDNA cloning and 1.75 angstrom crystal structure determination of PPL2, an endochitinase and N-acetylglucosamine-binding hemagglutinin from Parkia platycephala seeds

Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP-HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407 +/- 15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N-acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed beta(1-4) glycosidic bonds linking 2-acetoamido-2-deoxy-beta-D-glucopyranose units in chitin. The full-lengthamino acid sequence of Parkia platycephala lectin 2, determined by N-terminal sequencing and cDNA cloning, and its three-dimensional structure, established by X-ray crystallography at 1.75 angstrom resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (beta alpha)(8) barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182.

Characterization of a thermostable extracellular tannase produced under submerged fermentation by Aspergillus ochraceus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Extracellular tannase from Emericella nidulans showing hypertolerance to temperature and organic solvents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mecanismos de ação e controle da digestão de proteínas e peptídios em humanos

This review aims to report the major control mechanisms of protein and peptides digestion of special interest in human patients. Regarding protein assimilation its digestive process begins at the stomach with some not so indispensable actions comparatively to those of duodenal/jejunal lumen. However even the intestine processes are partially under gastric secretion control. Proteolytic enzyme activities are related to protein structure and amino acid constituents, tertiary and quartenary structures need HCl - denaturation prior to enzymatic hydrolysis. Thereafter the exopeptidases are guided by either NH 2 (aminopeptidases) or COOH (carboxypeptidases) terminals of the molecule while endopeptidases are oriented by the specific amino acids constituents of the peptide. Both dietary and luminal secreted proteins and polypeptides undergo to either limited or complete proteolysis resulting basic or neutral free-amino acids (40%) or dioctapeptides. The brush border peptidases continue to degrade oligopeptide to di-tripeptides and neutral free-amino acids. Some peptides are uptaked by the enterocytes whose cytosolic peptidases complete the hydrolysis. Hence the digestive products flowing in the portal vein are mainly free-amino acids from either luminal or cytosolic hydrolysis and some di-tripeptides intactly absorbed. Both mechanical and chemical processes of digestion are under neural (vagal), neuroendocrinal(acetilcholine),endocrinal(gastrin, secretin and cholecystokinin) or paracrinal (histamine) controls. The gastric phase (hydrochloric acid and pepsinogen secretions) is activated by gastrin, histamine and acetilcholine which respond to both dietary-amino acids (tryptophan and phenylalanine) and mechanic distention of stomach. The pancreatic secretion is stimulated by either cephalic or gastric phases and has influence on the intestinal phase of digestion. The intestinal types of cells S and I release secretin and cholecystokinin respectively in response of acid quimo (cells S) or amino acids and peptides (cells I) in the lumen. Secretin stimulates the releasing of water, bicarbonate and enteropeptidases whereas cholecystokinin acts on pancreatic enzymes.

Changes in protein fractions, trypsin inhibitor and proteolytic activity in the cotyledons of germinating chickpea

The chickpea seed germination was carried out in 6 days. During the period it was observed a little variation on total nitrogen contents, however the non protein nitrogen was double. A decrease of 19.1 and 20.6% in relation to total nitrogen was observed to the total globulin and albumin fractions, respectively. The gel filtration chromatography on Sepharose CL-6B and SDS-PAGE demonstrated alterations on the distribution patterns of the albumin and total globulin fractions between the initial and the sixth day of germination suggesting the occurrence of protein degradation in the germination process.The assay for acid protease only appeared in the albumin fraction with casein and chickpea total globulin as substrates, whereas the former was more degradated than the latter, however the transformations detected in the protein fractions apppear indicated that others enzymes could be acting during the process. The trypsin inhibitor activity had a little drop after six day of germination indicating a possible increase on the digestibility of the proteins.

Hydrolases in the hypopharyngeal glands of workers of Scaptotrigona postica and Apis mellifera (Hymenoptera, Apinae)

Hydrolytic enzymes from hypopharyngeal gland extracts of newly emerged, nurse and foraging workers of two eusocial bees, Scaptotrigona postica, a native Brazilian stingless bee, and the Africanized honey bee (Apis mellifera) in Brazil, were compared. The hypopharyngeal gland is rich in enzymes in both species. Fifteen different enzymes were found in the extracts, with only a few quantitative differences between the species. Some of the enzymes present in the extracts may have intracellular functions, while others seem to be digestive enzymes. Scaptotrigona postica, had lower β-glucosidase and higher lipase esterase activities than A. mellifera. The differences may be due to different feeding habits and behavioral peculiarities of the two species. ©FUNPEC-RP.

cDNA cloning and 1.75 Å crystal structure determination of PPL2, an endochitinase and N-acetylglucosamine-binding hemagglutinin from Parkia platycephala seeds

Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP-HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407 ± 15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N-acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed β(1-4) glycosidic bonds linking 2-acetoamido-2-deoxy-β-d-glucopyranose units in chitin. The full-length amino acid sequence of Parkia platycephala lectin 2, determined by N-terminal sequencing and cDNA cloning, and its three-dimensional structure, established by X-ray crystallography at 1.75 Å resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (βα) 8 barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182. © 2006 The Authors.

Pectin and pectinases: Production, characterization and industrial application of microbial pectinolytic enzymes

Pectinases are a big group of enzymes that break down pectic polysaccharides of plant tissues into simpler molecules like galacturonic acids. It has long been used to increase yields and clarity of fruit juices. Since pectic substances are a very complex macromolecule group, various pectinolytic enzymes are required to degrade it completely. These enzymes present differences in their cleavage mode and specificity being basically classified into two main groups that act on pectin smooth regions or on pectin hairy regions. Pectinases are one of the most widely distributed enzymes in bacteria, fungi and plants. This review describes the pectinolytic enzymes and their substrates, the microbial pectinase production and characterization, and the industrial application of these enzymes. © Pedrolli et al.; Licensee Bentham Open.

Characterization of a tannase from Emericela nidulans immobilized on ionic and covalent supports for propyl gallate synthesis

The extracellular tannase from Emericela nidulans was immobilized on different ionic and covalent supports. The derivatives obtained using DEAE-Sepharose and Q-Sepharose were thermally stable from 60 to 75 °C, with a half life (t50) >24 h at 80 °C at pH 5. 0. The glyoxyl-agarose and amino-glyoxyl derivatives showed a thermal stability which was lower than that observed for ionic supports. However, when the stability to pH was considered, the derivatives obtained from covalent supports were more stable than those obtained from ionic supports. DEAE-Sepharose and Q-Sepharose derivatives as well as the free enzyme were stable in 30 and 50 % (v/v) 1-propanol. The CNBr-agarose derivative catalyzed complete tannic acid hydrolysis, whereas the Q-Sepharose derivative catalyzed the transesterification reaction to produce propyl gallate (88 % recovery), which is an important antioxidant. © 2012 Springer Science+Business Media Dordrecht.