PubMed:29983742 JSONTXT

{"project":"ngly1-sample5","denotations":[{"id":"T1","span":{"begin":115,"end":137},"obj":"chem:24139"},{"id":"T4","span":{"begin":294,"end":300},"obj":"chem:24139"},{"id":"T5","span":{"begin":473,"end":479},"obj":"chem:24139"},{"id":"T6","span":{"begin":1360,"end":1366},"obj":"chem:24139"},{"id":"T7","span":{"begin":1672,"end":1678},"obj":"chem:24139"},{"id":"T8","span":{"begin":1973,"end":1979},"obj":"chem:24139"},{"id":"T9","span":{"begin":162,"end":193},"obj":"chem:24139"}],"text":"Molecular characterization of a novel chitinase CmChi1 from Chitinolyticbacter meiyuanensis SYBC-H1 and its use in N-acetyl-d-glucosamine production.\nBackground: N-acetyl-d-glucosamine (GlcNAc) possesses many bioactivities that have been used widely in many fields. The enzymatic production of GlcNAc is eco-friendly, with high yields and a mild production process compared with the traditional chemical process. Therefore, it is crucial to discover a better chitinase for GlcNAc production from chitin.\nResults: A novel chitinase gene (Cmchi1) cloned from Chitinolyticbacter meiyuanensis SYBC-H1 and expressed in Escherichia coli BL21(DE3) cells. The recombinant enzyme (CmChi1) contains a glycosyl hydrolase family 18 catalytic module that shows low identity (12-27%) with the corresponding domain of the well-characterized chitinases. CmChi1 was purified with a recovery yield of 89% by colloidal chitin affinity chromatography, whereupon it had a specific activity of up to 15.3 U/mg. CmChi1 had an approximate molecular mass of 70 kDa after the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its optimum activity for colloidal chitin (CC) hydrolysis occurred at pH 5.2 and 50 °C. Furthermore, CmChi1 exhibited kcat/Km values of 7.8 ± 0.11 mL/s/mg and 239.1 ± 2.6 mL/s/μmol toward CC and 4-nitrophenol N,N'-diacetyl-β-d-chitobioside [p-NP-(GlcNAc)2], respectively. Analysis of the hydrolysis products revealed that CmChi1 exhibits exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities toward N-acetyl chitooligosaccharides (N-acetyl CHOS) and CC substrates, behavior that makes it different from typical reported chitinases. As a result, GlcNAc could be produced by hydrolyzing CC using recombinant CmChi1 alone with a yield of nearly 100% and separated simply from the hydrolysate with a high purity of 98%.\nConclusion: The hydrolytic properties and good environmental adaptions indicate that CmChi1 has excellent potential in commercial GlcNAc production. This is the first report on exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities from Chitinolyticbacter species."}

{"project":"NGLY1-deficiency","denotations":[{"id":"PD-NGLY1-deficiency-B_T1","span":{"begin":186,"end":192},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T2","span":{"begin":294,"end":300},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T3","span":{"begin":473,"end":479},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T4","span":{"begin":1360,"end":1366},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T5","span":{"begin":1672,"end":1678},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T6","span":{"begin":1973,"end":1979},"obj":"chem:24139"},{"id":"T1","span":{"begin":186,"end":192},"obj":"chem:24139"},{"id":"T2","span":{"begin":294,"end":300},"obj":"chem:24139"},{"id":"T3","span":{"begin":473,"end":479},"obj":"chem:24139"},{"id":"T4","span":{"begin":1360,"end":1366},"obj":"chem:24139"},{"id":"T5","span":{"begin":1672,"end":1678},"obj":"chem:24139"},{"id":"T6","span":{"begin":1973,"end":1979},"obj":"chem:24139"}],"namespaces":[{"prefix":"hgnc","uri":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:"},{"prefix":"omim","uri":"https://www.omim.org/entry/"},{"prefix":"chem","uri":"https://pubchem.ncbi.nlm.nih.gov/compound/"}],"text":"Molecular characterization of a novel chitinase CmChi1 from Chitinolyticbacter meiyuanensis SYBC-H1 and its use in N-acetyl-d-glucosamine production.\nBackground: N-acetyl-d-glucosamine (GlcNAc) possesses many bioactivities that have been used widely in many fields. The enzymatic production of GlcNAc is eco-friendly, with high yields and a mild production process compared with the traditional chemical process. Therefore, it is crucial to discover a better chitinase for GlcNAc production from chitin.\nResults: A novel chitinase gene (Cmchi1) cloned from Chitinolyticbacter meiyuanensis SYBC-H1 and expressed in Escherichia coli BL21(DE3) cells. The recombinant enzyme (CmChi1) contains a glycosyl hydrolase family 18 catalytic module that shows low identity (12-27%) with the corresponding domain of the well-characterized chitinases. CmChi1 was purified with a recovery yield of 89% by colloidal chitin affinity chromatography, whereupon it had a specific activity of up to 15.3 U/mg. CmChi1 had an approximate molecular mass of 70 kDa after the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its optimum activity for colloidal chitin (CC) hydrolysis occurred at pH 5.2 and 50 °C. Furthermore, CmChi1 exhibited kcat/Km values of 7.8 ± 0.11 mL/s/mg and 239.1 ± 2.6 mL/s/μmol toward CC and 4-nitrophenol N,N'-diacetyl-β-d-chitobioside [p-NP-(GlcNAc)2], respectively. Analysis of the hydrolysis products revealed that CmChi1 exhibits exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities toward N-acetyl chitooligosaccharides (N-acetyl CHOS) and CC substrates, behavior that makes it different from typical reported chitinases. As a result, GlcNAc could be produced by hydrolyzing CC using recombinant CmChi1 alone with a yield of nearly 100% and separated simply from the hydrolysate with a high purity of 98%.\nConclusion: The hydrolytic properties and good environmental adaptions indicate that CmChi1 has excellent potential in commercial GlcNAc production. This is the first report on exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities from Chitinolyticbacter species."}