Browse
Submit Data
Databases
API
Help

Dataset Information

4 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A super-secondary structure predicted to be common to several alpha-1,4-D-glucan-cleaving enzymes.

ABSTRACT: Predictions of protein secondary structure are used with amino acid sequence alignments to show that the N-terminal domains of cyclodextrin glucanotransferases and a yeast alpha-glucosidase may have the same super-secondary structure as alpha-amylases, i.e. an (alpha/beta)8-barrel fold. Sequence similarities provide evidence that glucanotransferases, and possibly the glucosidase, are, like alpha-amylases, Ca2+-containing enzymes. The relationship between substrate specificity and the nature of the amino acid residues proposed at the active site is discussed for the transferases and alpha-glucosidase. A set of three programs for an Apple IIe computer to carry out the calculations described by Garnier, Osguthorpe & Robson [(1978) J. Mol. Biol. 120, 97-120] and a set of four programs for an Apple IIe computer to carry out the calculations described by Levin, Robson & Garnier [(1986) FEBS Lett. 205, 303-308] have been deposited as Supplementary Publication SUP 50149 (25 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257, 5.

SUBMITTER: MacGregor EA

PROVIDER: S-EPMC1138484 | biostudies-other | 1989 Apr

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

A promiscuous glycosyltransferase generates poly-β-1,4-glucan derivatives that facilitate mass spectrometry-based detection of cellulolytic enzymes.

Project description:Promiscuous activity of a glycosyltransferase was exploited to polymerise glucose from UDP-glucose via the generation of β-1,4-glycosidic linkages. The biocatalyst was incorporated into biocatalytic cascades and chemo-enzymatic strategies to synthesise cello-oligosaccharides with tailored functionalities on a scale suitable for employment in mass spectrometry-based assays. The resulting glycan structures enabled reporting of the activity and selectivity of celluloltic enzymes.

| S-EPMC8243248 | biostudies-literature

Safety evaluation of food enzyme glucan 1,4-α-maltohydrolase produced with a genetically modified Bacillus subtilis (strain MAM).

Project description:The food enzyme considered in this opinion is a glucan 1,4-α-maltohydrolase (maltogenic α-amylase; EC 3.2.1.133) produced with the genetically modified Bacillus subtilis strain MAM by the company DSM Food Specialties B. V. The food enzyme contains neither the production microorganism nor recombinant DNA; therefore, no environmental risk assessment is required. However, the Panel emphasises that this conclusion only covers the food enzyme recovered via filter press. The glucan 1,4-α-maltohydrolase is intended for use in baking processes. Based on the maximum use levels recommended and individual consumption data from the EFSA Comprehensive European Food Consumption Database, dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.175 mg TOS/kg body weight (bw) per day in European populations. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rodents. A no observed adverse effect level (NOAEL) was derived (986 mg TOS/kg bw per day for both males and females), which, compared with the dietary exposure, results in a sufficiently high margin of exposure. The allergenicity was evaluated by comparing the amino acid sequence to those of known allergens; one match was found. However, the Panel considered that there are no indications for food allergic reactions to this glucan 1,4-α-maltohydrolase by dietary exposure. No safety concerns were identified in relation to the genetic modifications, the manufacturing process, the compositional data provided, as well as the exposure, allergenicity and systemic toxicity assessments. However, owing to the incompleteness of the genotoxicity data, the Panel is not able to conclude on the safety of the food enzyme.

| S-EPMC7009641 | biostudies-literature

Crystal structure of α-1,4-glucan lyase, a unique glycoside hydrolase family member with a novel catalytic mechanism.

Project description:α-1,4-Glucan lyase (EC 4.2.2.13) from the red seaweed Gracilariopsis lemaneiformis cleaves α-1,4-glucosidic linkages in glycogen, starch, and malto-oligosaccharides, yielding the keto-monosaccharide 1,5-anhydro-D-fructose. The enzyme belongs to glycoside hydrolase family 31 (GH31) but degrades starch via an elimination reaction instead of hydrolysis. The crystal structure shows that the enzyme, like GH31 hydrolases, contains a (β/α)8-barrel catalytic domain with B and B' subdomains, an N-terminal domain N, and the C-terminal domains C and D. The N-terminal domain N of the lyase was found to bind a trisaccharide. Complexes of the enzyme with acarbose and 1-dexoynojirimycin and two different covalent glycosyl-enzyme intermediates obtained with fluorinated sugar analogues show that, like GH31 hydrolases, the aspartic acid residues Asp(553) and Asp(665) are the catalytic nucleophile and acid, respectively. However, as a unique feature, the catalytic nucleophile is in a position to act also as a base that abstracts a proton from the C2 carbon atom of the covalently bound subsite -1 glucosyl residue, thus explaining the unique lyase activity of the enzyme. One Glu to Val mutation in the active site of the homologous α-glucosidase from Sulfolobus solfataricus resulted in a shift from hydrolytic to lyase activity, demonstrating that a subtle amino acid difference can promote lyase activity in a GH31 hydrolase.

| S-EPMC3772222 | biostudies-literature

Alpha-Gal Syndrome: Involvement of Amblyomma americanum α-D-Galactosidase and β-1,4 Galactosyltransferase Enzymes in α-Gal Metabolism.

Project description:Alpha-Gal Syndrome (AGS) is an IgE-mediated delayed-type hypersensitivity reaction to the oligosaccharide galactose-α-1, 3-galactose (α-gal) injected into humans from the lone-star tick (Amblyomma americanum) bite. Indeed, α-gal is discovered in salivary glands of lone-star tick; however, the tick's specific intrinsic factors involved in endogenous α-gal production and presentation to host during hematophagy are poorly understood. This study aimed to investigate the functional role of two tick enzymes, α-D-galactosidase (ADGal) and β-1,4 galactosyltransferases (β-1,4GalT), in endogenous α-gal production, carbohydrate metabolism, and N-glycan profile in lone-star tick. The ADGal enzyme cleaves terminal α-galactose moieties from glycoproteins and glycolipids, whereas β-1,4GalT transfers α-galactose to a β1,4 terminal linkage acceptor sugars-GlcNAc, Glc, and Xyl-in various processes of glycoconjugate synthesis. An RNA interference approach was utilized to silence ADGal and β-1,4GalT in Am. americanum to examine their function in α-gal metabolism in tick and AGS onset. Silencing of ADGal led to the significant downregulation of genes involved in galactose metabolism and transport in Am. americanum. Immunoblot and N-glycan analysis of the Am. americanum salivary glands showed a significant reduction in α-gal levels in silenced tissues. However, there was no significant difference in the level of α-gal in β-1,4GalT-silenced tick salivary glands. A basophil-activation test showed a decrease in the frequency of activated basophil by ADGal-silenced salivary glands. These results provide an insight into the roles of ADGal and β-1,4GalT in α-gal production and presentation in ticks and the probable involvement in the onset of AGS.

| S-EPMC8671611 | biostudies-literature

1,4-D-Glucan block copolymers: synthesis and comprehensive structural characterization.

Project description:Multi-block glucans comprising permethylated and partially methylated blocks are compounds of interest. In order to monitor their formation by transglycosylation of corresponding starting glucans, a method has been developed and applied to model compounds. This method allows determining the average length of the blocks and the progress of incorporation of methyl blocks in partially methylated sequences with a random distribution. The method, comprising liquid chromatography mass spectrometry (LC-MS) and electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MSn) measurements of two types of peralkylated glucans representing derivatives of the target compounds, is comprehensively described and discussed. ESI-MSn allows looking into the sequences of oligomeric domains. In addition, transglycosylation is followed by attenuated total reflection FTIR and NMR spectroscopy. Graphical abstract.

| S-EPMC7026270 | biostudies-literature

Aspergillus niger genome-wide analysis reveals a large number of novel alpha-glucan acting enzymes with unexpected expression profiles.

Project description:The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material. A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of alpha-amylase, glucoamylase and alpha-glucosidase enzymes, members of the glycoside hydrolase (GH) families 13, 15 and 31, respectively. In this study we have combined analysis of the genome sequence of A. niger CBS 513.88 with microarray experiments to identify novel enzymes from these families and to predict their physiological functions. We have identified 17 previously unknown family GH13, 15 and 31 enzymes in the A. niger genome, all of which have orthologues in other aspergilli. Only two of the newly identified enzymes, a putative alpha-glucosidase (AgdB) and an alpha-amylase (AmyC), were predicted to play a role in starch degradation. The expression of the majority of the genes identified was not induced by maltose as carbon source, and not dependent on the presence of AmyR, the transcriptional regulator for starch degrading enzymes. The possible physiological functions of the other predicted family GH13, GH15 and GH31 enzymes, including intracellular enzymes and cell wall associated proteins, in alternative alpha-glucan modifying processes are discussed.

| S-EPMC2413074 | biostudies-literature

Safety evaluation of the food enzyme glucan 1,4-α-maltohydrolase from the genetically modified Bacillus licheniformis strain NZYM-CY.

Project description:The food enzyme glucan 1,4-α-maltohydrolase (4-α-d-glucan α-maltohydrolase; 3.2.1.133) is produced with the genetically modified Bacillus licheniformis strain NZYM-CY by Novozymes A/S. The genetic modifications did not give rise to safety concerns. The production strain has been shown to qualify for Qualified Presumption of Safety (QPS) status. The food enzyme is free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in three food manufacturing processes, namely baking and brewing processes and starch processing for glucose syrup production and other starch hydrolysates. Since residual amounts of total organic solids (TOS) are removed by the purification steps applied during the production of glucose syrups, dietary exposure was calculated only for the baking and brewing processes. Dietary exposure was estimated to be up to 0.45 mg TOS/kg body weight (bw) per day in European populations. Given the QPS status of the production strain and the lack of hazards resulting from the food enzyme manufacturing process, toxicological studies were not considered necessary. Similarity of the amino acid sequence to those of known allergens was searched and four matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood of such reactions to occur is considered to be low. Based on the data provided, the QPS status of the production strain and the absence of issues arising from the production process, the Panel concluded that the food enzyme glucan 1,4-α-maltohydrolase produced with the genetically modified B. licheniformis strain NZYM-CY does not give rise to safety concerns under the intended conditions of use.

| S-EPMC9202445 | biostudies-literature

Safety evaluation of the food enzyme glucan 1,4-α-maltohydrolase from the genetically modified Bacillus licheniformis strain NZYM-SD.

Project description:The food enzyme glucan 1,4-α-maltohydrolase (4-α-d-glucan α-maltohydrolase; 3.2.1.133) is produced with the genetically modified Bacillus licheniformis strain NZYM-SD by Novozymes A/S. The genetic modifications did not give rise to safety concerns. The production strain has been shown to qualify for Qualified Presumption of Safety (QPS) status. The food enzyme is free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in three food manufacturing processes, namely baking processes and brewing processes and starch processing for glucose syrup production and other starch hydrolysates. Since residual amounts of total organic solids (TOS) are removed by the purification steps applied during the production of glucose syrups, dietary exposure was calculated only for baking and brewing processes. Dietary exposure was estimated to be up to 0.57 mg TOS/kg body weight (bw) per day in European populations. Given the QPS status of the production strain and the lack of hazards resulting from the food enzyme manufacturing process, toxicological studies were not considered necessary. Similarity of the amino acid sequence to those of known allergens was searched and four matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood of such reactions to occur is considered to be low. Based on the data provided, the QPS status of the production strain and the absence of issues arising from the production process, the Panel concluded that the food enzyme glucan 1,4-α-maltohydrolase produced with the genetically modified B. licheniformis strain NZYM-SD does not give rise to safety concerns under the intended conditions of use.

| S-EPMC9200369 | biostudies-literature

Safety evaluation of the food enzyme glucan 1,4-α-glucosidase from the genetically modified Aspergillus niger strain NZYM-BE.

Project description:The food enzyme glucan 1,4-α-glucosidase (4-α-d-glucan glucohydrolase EC 3.2.1.3) is produced with the genetically modified Aspergillus niger strain NZYM-BE by Novozymes A/S. The genetic modifications do not give rise to safety concerns. The food enzyme was free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in six food manufacturing processes, namely starch processing for the production of glucose syrups and other starch hydrolysates, distilled alcohol production, brewing processes, baking processes, cereal-based processes, and fruit and vegetable processing for juice production. Since residual amounts of total organic solids (TOS) are removed by distillation and by the purification steps applied to produce glucose syrups, dietary exposure was not calculated for these two food processes. For the remaining four processes, dietary exposure to the food enzyme-TOS was estimated to be up to 7.7 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 3,795 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure above 490. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched for and one match found. The Panel considered that, under the intended conditions of use (other than distilled alcohol production) the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

| S-EPMC9244779 | biostudies-literature

Safety evaluation of the food enzyme glucan 1,4-α-maltohydrolase from the genetically modified Bacillus licheniformis strain NZYM-FR.

Project description:The food enzyme glucan 1,4-α-maltohydrolase (4-α-d-glucan α-maltohydrolase; 3.2.1.133) is produced with the genetically modified Bacillus licheniformis strain NZYM-FR by Novozymes A/S. The genetic modifications did not give rise to safety concerns. The production strain has been shown to qualify for Qualified Presumption of Safety (QPS) status. The food enzyme is free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in three food manufacturing processes, namely baking and brewing processes and starch processing for glucose syrup production and other starch hydrolysates. Since residual amounts of total organic solids (TOS) are removed by the purification steps applied during the production of glucose syrups, dietary exposure was calculated only for the baking and brewing processes. Dietary exposure was estimated to be up to 0.30 mg TOS/kg body weight (bw) per day in European populations. Given the QPS status of the production strain and the lack of hazards resulting from the food enzyme manufacturing process, toxicological studies were not considered necessary. Similarity of the amino acid sequence to those of known allergens was searched and four matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood of such reactions to occur is considered to be low. Based on the data provided, the QPS status of the production strain and the absence of issues arising from the production process, the Panel concluded that the food enzyme glucan 1,4-α-maltohydrolase produced with the genetically modified B. licheniformis strain NZYM-FR does not give rise to safety concerns under the intended conditions of use.

| S-EPMC9199875 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data