• KSBB Journal
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• v.21 no.4
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• pp.298-301
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• 2006

A gene(GeneBank AF 135796) coding for a trehalose synthase from Thermus caldophilus GK24 was cloned into Escherichia coli K12 using five vector systems. The constitutive expression system(pHCETS) which shows the highest trehalose synthase activity from flask culture of recombinant E. coli was selected for the production of trehalose from maltose. For the shake flask culture, the final dry cell weight was 0.9 g/L and the trehalose synthase activity was 25 U/mL. Fed-batch culture of recombinant E. coli harboring plasmid pHCETS which uses the glycerolas a carbon source was performed in jar fermentor: the dry cell weight of 20 g/L and the trehalose synthase activity of 13.7 U/mL were attained in 48 h.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.275-280
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• 2000

The inulin fructotransferse (depolymerizing) (IFTase, EC 2.4.1.93) gene of Arthrobacter sp. A-6 was cloned and expressed in Escherichia coli and Bacillus subtilis. The IFTase gene consisted of an ORF of 1.311 nucleotides encoding a polypeptide of 436 amino acids containing a signal peptide of 31 amino acids in the N-terminus. The molecular mass of the IFTase based on the nucleotide sequence was calculated to be 46.116 Da. The recombinant E. coli $DH5{\alpha}$ cells expressing the Arthrobacter sp. A-6 IFTase gene produced most of the IFTase intracelularly. In contrast, the recombinant B. subtilis DB 104 carrying the IFTas gene on a B. subtilis-E. Coli expression vector secreted the IFTase into the culture fluid efficiently.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.827-831
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• 2007

Myostatin is a member of the transforming growth factor-${\beta}$(TGF-${\beta}$ super-family. It acts as a negative regulator for skeletal muscle growth. Myostatin mutations are characterized by a visible, generalized increase in muscle mass in double muscled cattle breeds. To understand the biochemistry and physiology of the Chinese Yellow bovine myostatin gene, we report here for the first time expression of the gene in Escherichia coli (E. coli). Primers of the myostatin gene of Chinese Yellow Cattle were designed on the basis of the reported bovine myostatin mRNA sequence (Gen-Bank Accession No. NM005259) and optimized for E. coli codon usage. XhoI and EcoRI restriction enzyme sites were incorporated in the primers, and then cloning vector and expression vector were constructed in a different host bacterium. The expressed protein had a molecule mass of about 16 kDa as determined by SDS-PAGE under reducing conditions. The expressed protein reacted specifically with myostatin monoclonal antibody on immunoblots. Our studies should lead to the investigation of the differences in myostatin genes of various cattle and could benefit human health and food animal agriculture.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.974-977
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• 2010

Cyclophilins contain the conserved activity of cis-trans peptidyl-prolyl isomerase, which is implicated in protein folding, and function as molecular chaperones. When the yeast cyclophilin A gene (cpr1) was subcloned into the prokaryotic expression vector pKM260, it was found that the expression of Cpr1 drastically increased the cell viability of E. coli BL21 when under abiotic stress conditions, as in the presence of cadmium, copper, hydrogen peroxide, heat, and SDS. Therefore, this study illustrates the importance of Cpr1 as a molecular chaperone that can improve the cellular stress responses when E. coli cells are exposed to adverse conditions, while also demonstrating its potential to increase the stability of E. coli strains utilized for the production of recombinant proteins.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.14-17
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUC19 to yield plasmid pLCl. The Pseudomonas sp. LBC505 endoglucanase gene was subcloned in a temperature-regulated Es-cherichia coli expression vector, pAS1, containing the leftward promoter $P_L$ of bacteriophage lambda. The level of gene expression was controlled by the thermal inactivation of the heat-sensitive lambda cI857 repressor. Best yield of endoglucanase was obtained by lowering the incubation temperature to $37^{\circ}C$ after induction at $42^{\circ}C$ for 1h. Under these conditions enzyme production continued for about 5h at a gradually decreasing rate. Ecoli harboring recombinant plasmid pASC10 expressed 4.3 times as much CMCase activity as E.coli containing pLCl. To enhance the expression level of endogl, ucanase gene, we have also changed the presumptive Shine-Dalgamo sequence (AGAGGT) of the gene to consensus sequence (AGGAGGT) by site-directed mutagenesis. The genes mutated were subcloned in pASl resulting in the formation of recombinant plasmid pASS50. E.coli harboring the plasmid pASS50 expressed 6.2-fold higher levels of CMCase activity than that of E.coli harboring pLC1.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1243-1250
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• 2010

A cDNA encoding a cysteine protease inhibitor (CPI) was isolated from the cDNA library of clamworm Perinereis aibuhitensis Grube. The deduced amino acid sequence analysis showed that the protein had 51%, 48%, and 48% identity with Zgc:153129 from Danio rerio, cystatin B from Theromyzon tessulatum, and the ChainA, stefin B tetramer from Homo sapiens, respectively. The gene was cloned into the intracellular expression vector pET-15b and expressed in Escherichia coli. The recombinant CPI (PA-CPI) was purified by affinity chromatography on Ni-charged resin and ion-exchange chromatography on DEAE-Sepharose FF. The relative molecular mass of PA-CPI was 16 kDa as deduced by SDS-PAGE. Activity analysis showed that the recombinant protein could inhibit the proteolytic activity of papain. A constitutive and secretive expression vector was also constructed, and the cDNA encoding CPI was subcloned into the vector for extracellular expression. Western blotting analysis results showed that the PA-CPI was secreted into the medium. Bioassay demonstrated that E. coli DH5${\alpha}$ harboring pUC18ompAcat-CPI showed a significant difference in mortality to the Asian longhorned beetle Anoplophora glabripennis compared with untransformed E. coli DH5${\alpha}$ and control.

• Reproductive and Developmental Biology
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• v.35 no.3
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• pp.251-256
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• 2011

Human growth hormone (hGH), one of the most important hormones in medicine, is secreted from anterior pituitary gland. Its broad physiological function includes body growth, cell regeneration, increasement of muscle volume, bone density, body fat reduction, and so on. Due to the wide range of therapeutic effects, the hGH produced from E. coli has been commercialized already. In this study, we asked whether it is possible to produce recombinant hGH efficiently from various cultured mammalia cells. To meet this purpose, we chose a retrovirus vector system for transfer and expression of the hGH gene in various mammalian cells. Analyses of RT-PCR, ELISA, and Western blot to determine expression of the hGH gene showed the highest production of the hGH was determined from chicken embronic fibroblast (CEF) cells with the concentration of 8.58 ${\mu}g$/ml. The biological activity of the hGH was similar to the commercially available counterpart. These results suggest that mass production of hGH is possible not only in the E. coli but also in the various mammalian cells.

• Molecules and Cells
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• v.25 no.3
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• pp.446-451
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• 2008

We assessed heterologous protein expression in 64 strains obtained from the Escherichia coli Reference (ECOR) collection, a collection representing diverse natural E. coli populations. A plasmid generating a glutathione S-transferase and plant carbonic anhydrase fusion protein (GST-CA) under the control of the tac promoter was introduced into the ECOR strains, and the quantity of the fusion protein was determined by SDS-PAGE. The foreign protein was generated at various levels, from very high (40 strains, high producers) to very low (six strains, low producers). Immunoblotting showed that the high producers expressed approximately 250-500 times more GST-CA protein than the low producers. The results of semi-quantitative RT-PCR showed that the low producers generated mRNA levels comparable to those of the high producers, thereby suggesting that, at least in this case, inefficient translation is a major cause of the low production. We introduced a different plasmid, which expressed a maltose binding protein and plant guanylate kinase fusion protein (MBP-GK) into the six low producers. Interestingly, five of these expressed MBP-GK at very high levels. Thus, we conclude that the production of a particular protein from an expression vector can vary considerably, depending on the host strain. Strains in the ECOR collection could function as useful alternative hosts when a desired level of protein expression is not obtained from commonly used strains, such as E. coli K12 or B derivatives.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.287-291
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• 2003

Botulinum neurotoxin type A (BONT/A) is an extremely potent toxin, which is produced by Clostridium botulinum. The light chain of this protein (BONT/A LC), which is known as a zinc endopeptidase, cleaves SNAP-25 involved in the exocytosis process. In this work, the expression of recombinant BoNT/A LC in E. coli is described. The BONT/A LC gene of C. botulinum contains a high frequency of the arginine AGA and isoleucine ATA codons that are rarely used in genes of E. coli, hampering the translation of recombinant protein. The argD and ilex tRNA genes were cloned into pACYC184 vector, resulting in pAAD131X plasmid. The translational stress of the toxin gene related to codon bias was reversed by fupplernentation of the AGA arginyl tRNA of T4 phage and AUA isoleucyl tRNA of E. coli. This system may be applicable for the expression of a variety of AT-rich heterologous genes in E. coli.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.620-623
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• 2003

The delta sleep-inducing peptides (DSIP, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) is an important regulatory hormone, controlling hypothalamus and pituitary functions. In the current study, an expression system was designed for the rapid and economic expression oi recombinant DSIP for biophysical studies. Artificially synthesized oligonucleotides encoding DSIP were cloned into a pGEX-KG vector and expressed in E. coli (BL21). The recombinant GST-DSIP was then readily purified using a GST affinity column. To obtain intact DSIP from the GST-DSIP, thrombin cleavage and a CNBr reaction were successively carried out. The DSIP in the CNBr reaction mixture was subjected to RP-HPLC purification to yield 1.2 mg DSIP from a 1 liter culture of E. coli. Identification of the DSIP was peformed using MALDI-MS and an amino acid composition analysis.