The poly-alpha- and -beta-1,4-glucuronic acid moiety of teichuronopeptide from the cell wall of the alkalophilic Bacillus strain C-125.
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ABSTRACT:
SUBMITTER: Aono R
PROVIDER: S-EPMC1131730 | biostudies-other | 1990 Sep
REPOSITORIES: biostudies-other
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Project description:The cell wall of an alkalophilic strain of Bacillus sp. C-125 is composed of A1 gamma-peptidoglycan, a teichuronic acid and an unknown acidic polymer composed of glutamic acid and glucuronic acid, of which the molar ratio is approx. 4-5:1. Poly(gamma-L-glutamate) was prepared from the acidic polymer by removal of almost all of the glucuronic residues with trifluoromethanesulphonic acid treatment and purified chromatographically. The Mr of the polyglutamate preparation was estimated to be 14,000 by gel chromatography, or 43,000 on the basis of the content of N-terminal acid residues. The acidic polymer found in the cell wall of the organism was concluded to be a polyglutamate substituted with (oligo)glucuronic acid residues or a complex composed of two kinds of polymers (polyglutamate and polyglucuronate).
| S-EPMC1148145 | biostudies-other
Project description:Cell walls of the alkalophilic Bacillus strain C-125 are composed of gamma-peptidoglycan, teichuronic acid and a polymer of glucuronate and glutamate. An amino sugar that was a main component of the teichuronic acid did not correspond to any of the commercially available hexosamines. The amino sugar was purified into crystalline form from the hydrolysate of the teichuronic acid by ion-exchange chromatography and then partition chromatography on a cellulose column. The amino sugar was identified as D-fucosamine (2-amino-2,6-dideoxy-D-galactose) by 400 MHz n.m.r. spectrometric analysis, measurement of optical rotation and elemental analysis.
| S-EPMC1153020 | biostudies-other
Project description:The gene xyaA encoding an alkaline endo-beta 1,4-xylanase from an alkalophilic Bacillus sp. strain (N137) isolated in our laboratory was cloned and expressed in Escherichia coli. The nucleotide sequence of a 1,656-bp DNA fragment containing xyaA was determined, revealing one open reading frame of 993 bp that encodes a xylanase (XyaA) of 39 kDa. This xylanase lacks a typical putative signal peptide, yet the protein is found in the Bacillus culture supernatant. In Escherichia coli, the active protein is located mainly in the periplasmic space. The xylanase activity of the cloned XyaA is an endo-acting enzyme that shows optimal activity at pH 8 and 40 degrees C. This activity is stable at a pH between 6 and 11. Incubations of XyaA at 40 degrees C for 1 h destroyed 45% of the activity.
| S-EPMC167514 | biostudies-other
Project description:A GH67 α-glucuronidase gene derived from Bacillus halodurans C-125 was expressed in E. coli to obtain a recombinant enzyme (BhGlcA67). Using the purified enzyme, the enzymatic properties and substrate specificities of the enzyme were investigated. BhGlcA67 showed maximum activity at pH 5.4 and 45 °C. When BhGlcA67 was incubated with birchwood, oat spelts, and cotton seed xylan, the enzyme did not release any glucuronic acid or 4-O-methyl-glucuronic acid from these substrates. BhGlcA67 acted only on 4-O-methyl-α-D-glucuronopyranosyl-(1→2)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranose (MeGlcA3Xyl3), which has a glucuronic acid side chain with a 4-O-methyl group located at its non-reducing end, but did not on β-D-xylopyranosyl-(1→4)-[4-O-methyl-α-D-glucuronopyranosyl-(l→2)]-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylop- yranose (MeGlcA3Xyl4) and α-D-glucuronopyranosyl-(l→2)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranose (GlcA3Xyl3). The environment for recognizing the 4-O-methyl group of glucuronic acid was observed in all the crystal structures of reported GH67 glucuronidases, and the amino acids for discriminating the 4-O-methyl group of glucuronic acid were widely conserved in the primary sequences of the GH67 family, suggesting that the 4-O-methyl group is critical for the activities of the GH67 family.
| S-EPMC8056927 | biostudies-literature
Project description:The gene bgaA encoding an alkaline endo-beta-1,3-1,4-glucanase (lichenase) from an alkalophilic Bacillus sp. strain N137, isolated in our laboratory, was cloned and expressed from its own promoter in Escherichia coli. The nucleotide sequence of a 1,416-bp DNA fragment containing bgaA was determined and revealed an open reading frame of 828 nucleotides. The deduced protein sequence consists of 276 amino acids and has a 31-amino-acid putative signal peptide which is functional in E. coli, in which the BgaA protein is located mainly in the periplasmic space. The lichenase activity of BgaA is stable between pH 6 and 12, it shows optimal activity at a temperature between 60 and 70 degrees C, and it retains 65% of its activity after incubation at 70 degrees C for 1 h. This protein is similar to some other lichenases from Bacillus species such as B. amyloliquefaciens, B. brevis, B. licheniformis, B. macerans, B. polymyxa, and B. subtilis. However, it has a lysine-rich region at the carboxy terminus which is not found in any other published lichenase sequence and might be implicated in the unusual biochemical properties of this enzyme. The location of the mRNA 5' end was determined by primer extension and corresponds to nucleotide 235. A typical Bacillus sigma A promoter precedes the transcription start site.
| S-EPMC201461 | biostudies-other
Project description:Four tandem subtilisin-like protease genes were found on a 6,854-bp DNA fragment cloned from the alkalophilic Bacillus sp. strain LG12. The two downstream genes (sprC and sprD) appear to be transcribed independently, while the two upstream genes (sprA and sprB) seem to be part of the same transcript.
| S-EPMC167761 | biostudies-other
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
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
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
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