Improvement of Cucurbitacin B Content in Cucumis melo Pedicel Extracts by Biotransformation Using Recombinant β-Glucosidase

For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli BL21(DE3). The activity of recombinant β-glucosidase with p-nitrophenyl-β-d-glucoside (pNPG) as a substrate was 3.48 U/mL in a culture. Using the recombinant β-glucosidase for the biotransformation of C. melo pedicel extracts, CuBg was converted into CuB with a conversion rate of 87.6% when the concentration of CuBg was 0.973 g/L in a reaction mixtures. The concentration of CuB in C. melo pedicel extracts was improved from 13.6 to 20.2 g/L after biotransformation. The present study provides high-efficiency technology for the production of CuB from its glycoside by biotransformation.

Download Full-text

Enzymatic Bioconversion of Cholesterol Using Glucosyltransferase and Methyltransferase Isolated from Streptomyces

10.20944/preprints201804.0247.v1 ◽

2018 ◽

Author(s):

Niranjan Koirala

Keyword(s):

Escherichia Coli ◽

Amino Acids ◽

Full Length ◽

Streptomyces Avermitilis ◽

Accession Number ◽

Streptomyces Peucetius ◽

Escherichia Coli Bl21 ◽

Calculated Mass ◽

Enzymatic Bioconversion ◽

Full Length Gene

A sterol glycosyltransferases (SGT) gene (sav7185; accession number NP_828361) was isolated from Streptomyces avermitilis MA-4680. The full-length gene consists of 1284 nucleotides and encodes 427 amino acids with a calculated mass of 46.05 kDa. The gene was then cloned in pET28a vector and heterologously expressed in Escherichia coli BL21 (DE3) and was used for the biotransformation of cholesterol. This SGT protein showed favorable activity towards cholesterol tested in this study. Further, we tested the conversion of cholesterol to its methoxide using another Streptomyces O-methyltransferase (accession number KF420279). This O-methyltransferase (OMT) SpOMT2884, originating from Streptomyces peucetius ATCC 27952, was cloned, expressed, and applied for the production of methylated derivative. The GC-MS analysis confirmed the conversion of cholesterol into cholesterol-3-O-β-D-glucoside and a novel cholesterol-3-O-methoxide. Hence, these Streptomyces SGT and OMT could find applications for the derivatization of pharmaceutically significant sterols.

Download Full-text

Effects of Different Amino Acids on Biofilm Growth, Swimming Motility and Twitching Motility in Escherichia Coli BL21

Journal of Biology and Life Science ◽

10.5296/jbls.v4i2.3195 ◽

2013 ◽

Vol 4 (2) ◽

Cited By ~ 5

Author(s):

Seh-Nee Goh ◽

Amie Fernandez ◽

See-Zou Ang ◽

Wai-Yip Lau ◽

Di-Lin Ng ◽

...

Keyword(s):

Escherichia Coli ◽

Amino Acids ◽

Twitching Motility ◽

Biofilm Growth ◽

Swimming Motility ◽

Escherichia Coli Bl21

Download Full-text

Faculty Opinions recommendation of A comprehensive alanine scanning mutagenesis of the Escherichia coli transcriptional activator SoxS: identifying amino acids important for DNA binding and transcription activation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1011419.180017 ◽

2003 ◽

Author(s):

Juan Luis Ramos

Keyword(s):

Escherichia Coli ◽

Amino Acids ◽

Dna Binding ◽

Transcriptional Activator ◽

Transcription Activation ◽

Alanine Scanning Mutagenesis ◽

Alanine Scanning

Download Full-text

Expression and characterization of an α-glucosidase from Thermoanaerobacter ethanolicus JW200 with potential for industrial application

Biologia ◽

10.2478/s11756-009-0197-1 ◽

2009 ◽

Vol 64 (6) ◽

Cited By ~ 9

Author(s):

Yue-Hong Wang ◽

Yu Jiang ◽

Zuo-Ying Duan ◽

Wei-Lan Shao ◽

Hua-Zhong Li

Keyword(s):

Escherichia Coli ◽

Heat Shock ◽

Optimal Condition ◽

Industrial Application ◽

Conversion Rate ◽

Hydrolytic Activity ◽

Thermoanaerobacter Ethanolicus ◽

Transglycosylation Activity

AbstractIn this study, a new α-glucosidase gene from Thermoanaerobacter ethanolicus JW200 was cloned and expressed in Escherichia coli by a novel heat-shock vector pHsh. The recombinant α-glucosidase exhibited its maximum hydrolytic activity at 70°C and pH 5.0∼5.5. With p-nitrophenyl-α-D-glucoside as a substrate and under the optimal condition (70°C, pH 5.5), K m and V max of the enzyme was 1.72 mM and 39 U/mg, respectively. The purified α-glucosidase could hydrolyze oligosaccharides with both α-1,4 and α-1,6 linkages. The enzyme also had strong transglycosylation activity when maltose was used as sugar donor. The transglucosylation products towards maltose are isomaltose, maltotriose, panose, isomaltotriose and tetrasaccharides. The enzyme could convert 400 g/L maltose to oligosaccharides with a conversion rate of 52%, and 83% of the oligosaccharides formed were prebiotic isomaltooligosaccharides (containing isomaltose, panose and isomaltotriose).

Download Full-text