• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.748-755
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• 2014

In the genome annotation of Escherichia coli MG1655, the orf382 (1,149 bp) is designated as a gene encoding an alcohol dehydrogenase that may be Fe-dependent. In this study, the gene was amplified from the genome by PCR and overexpressed in Escherichia coli BL21(DE3). The recombinant $6{\times}$His-tag protein was then purified and characterized. In an enzymatic assay using different hydroxyl-containing substrates (n-butanol, $\small{L}$-threonine, ethanol, isopropanol, glucose, glycerol, $\small{L}$-serine, lactic acid, citric acid, methanol, or $\small{D}$-threonine), the enzyme showed the highest activity on $\small{L}$-threonine. Characterization of the mutant constructed using gene knockout of the orf382 also implied the function of the enzyme in the metabolism of $\small{L}$-threonine into glycine. Considering the presence of tested substrates in living E. coli cel ls and previous literature, we believed that the suitable nomenclature for the enzyme should be an $\small{L}$-threonine dehydrogenase (LTDH). When using $\small{L}$-threonine as the substrate, the enzyme exhibited the best catalytic performance at $39^{\circ}C$ and pH 9.8 with $NAD^+$ as the cofactor. The determination of the Km values towards $\small{L}$-threonine (Km = $11.29{\mu}M$), ethanol ($222.5{\mu}M$), and n-butanol ($8.02{\mu}M$) also confirmed the enzyme as an LTDH. Furthermore, the LTDH was shown to be an ion-containing protein based on inductively coupled plasma-atomic emission spectrometry with an isoelectronic point of pH 5.4. Moreover, a circular dichroism analysis revealed that the metal ion was structurally and enzymatically essential, as its deprivation remarkably changed the ${\alpha}$-helix percentage (from 12.6% to 6.3%).

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.94-100
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• 2011

A gene encoding a putative phospholipase D was isolated from Bacillus licheniformis and cloned into pGEM-T easy vector. The gene was expressed in E. coli BL21 (DE3) using a pET-21(a) vector containing His6 tag. Affinity purification of the recombinant phospholipase D with nickel-nitrilotriacetic acid (Ni-NTA) resin resulted major one-band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The purified enzyme showed a molecular weight of 44 kDa. The optimum activity of enzyme was around pH 7.0 and the enzyme was also the most stable around this condition. The optimum temperature was about $40-45^{\circ}C$ and the enzyme still showed considerable activities at wide range of temperature. Among various detergents, Triton X-100 significantly increased the enzyme activity, resulting in 181% activity of control at 0.6 mM of the detergent. Calcium ion did not significantly affect the enzyme activity, suggesting that the enzyme might be classified into $Ca^{2+}$-independent PLD.

• Restorative Dentistry and Endodontics
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• v.32 no.5
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• pp.459-468
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• 2007

Protein microarray or protein chips is potentially powerful tools for analysis of protein-protein interactions. APin cDNA was previously identified and cloned from a rat odontoblast cDNA library. The purpose of this study was to investigate the APin-protein interactions during ameloblast differentiation. Protein microarray was carried with recombinant APin protein and MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein were selected among 74 interacting proteins. Immortalized ameloblast cells (ALCs) were transfected with pCMV-APin construct and U6-APin siRNA construct. After transfection, the expression of the mRNAs for four proteins selected by protein micoarrays were assessed by RT-PCR. The results were as follows: 1. APin expression was increased and decreased markedly after its over-expression and inactivation, respectively. 2. Over-expression of the APin in the ALCs markedly down-regulated the expression of MEF2 and Aurora kinase A, whereas their expression remained unchanged by its inactivation. 3. Expression of BMPR-IB and EF-hand calcium binding protein were markedly increased by the over-expression of the APin in the ALCs, whereas expression of BMPR-IB remained unchanged and expression of EF-hand calcium binding protein was markedly decreased by its inactivation. These results suggest that APin plays an important role in ameloblast differentiation and mineralization by regulating the expression of MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.101-105
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• 2008

In order to obtain yeast cells producing a bacteriocin OR-7, the 180 bp polynucleotide corresponding to the OR-7 gene including codons for start and stop was chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Campylobacter jeuni, Escherichia coli and Pseudomonas aeruginosa. This result indicates that yeast cells producing OR-7 possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative C. jejuni, E. coli and P. aeruginosa cells. The recombinant yeast strain constructed in this study can be applied in the food preservative or animal feed.

• Journal of Life Science
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• v.20 no.2
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• pp.292-297
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• 2010

Anthocyanin, a phenolic compound, is a pigment that shows blue or red color in the fruit, petal and other tissues. It is an important factor in grape berry skin pigment and accumulates only in the skin. This skin-specific accumulation of anthocyanin has been reported to be regulated by the ufgt gene which encodes UDP-glucose: flavonoid 3-O-glucosyltransferase that participates in the biosynthesis of anthocyanin. The ufgt gene is expressed only in berry skin, while the other genes involved in the biosynthetic pathway are expressed in both skin and flesh tissues. In order to determine whether anthocyanin accumulation is primarily regulated by compartment of UFGT, a ufgt cDNA clone was isolated from grape berry, its open reading frame was ligated in pBI121 vector in either a sense or an antisense orientation under the control of the CaMV35S promoter and the recombinant constructs were incorporated into tobacco plants. Several transgenic lines were selected and characterized to determine the level of expression of the grapevine ufgt transcript and endogenous homologs of tobacco. Compared to the wild-type, the amount of anthocyanins in sense transgenic plants increased by 44%, while the amount of anthocyanins in antisense transgenic plants decreased by 88%. In addition, the color of flowers became intense in the sense transgenic plants. These results suggest that over-expression or repression of the ufgt gene affected the accumulation of anthocyanin in flowers of tobacco.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.97-97
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• 2002

Human eryhropoietin (EPO) is acidic glycoprotein hormone that plays key role in hematopoiesis by facilitating differentiation of erythrocyte and formation of hemoglobin (Hb) and is used for the treatment of anemia. Human EPO is consist of 166 amino acids which is modified by three N-glycosylations (24, 38, 83) and single O-glycosylation (126). N-glycosylation is reported to be related to the cellular secretion and activity of EPO. In this study, we examined effects of mutagenesis in glycosylation site of recombinat hEPO for the cellular secretion during production from cultured CHO cell. We produced rhEpo which was cloned by PCR from human liver cDNA (TaKaRa) in cultured CHO cell. Using supernatant of the culture, ELISA assay and western analysis were performed. To estimate biological activity, 20IU of rhuEpo was subcutaneously injected into four ICR mice. After 8 days, HCT level was increased average 13 per cent, RBC was increased ca. 2${\times}$10$\^$6//${\mu}\ell$. In disease model Rat (anemia c-kit, WSRC-WS/WS), HCT was increased ca. 12%, RBC was increased ca. 1.6${\times}$10$\^$6//${\mu}\ell$. These results suggests that rhEpo we produced has biological activity. To remove glycosylation site by substituting 24, 38, 83, and 126th asparagine (or serine) with glutamic acid, overlapping -extension site-directed mutagenesis was performed. To add novel glycosylation sites, 69, 105th leucine was mutated to asparagine. Mutant EPO construct was transfected into CHO cell. Supernatant of the cell culture was analyzed using ELISA assay with monoclonal anti-EPO antibody (Medac, Germany). Since, several reports for mutagenesis of glycosylation sites showed case-by-case results, we examined both transient expression and stable expression. Addition of novel glycosylation sites resulted no secretion while deletion mutants had little effect except some double deletion mutants (24/83 and 38/83) and triple mutant. We suggest that not single but combination of glycosyl group affect secretion of EPO.

• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.159-167
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• 2014

In eukaryotes, proteins that are secreted into ER are post-translationally modified by N-glycosylation, the patterns of which are significantly different between plant and animal cells. Biotechnology industry has already produced a number of therapeutic glycoproteins in plant cells. However, the aberrant glycosylation of therapeutic recombinant proteins in plant systems can cause immune problems in humans. Therefore, it is important to develop strategies for producing non-glycosylated forms to preserve biological activity and native conformation by a peptide: N-glycanase (PNGase). In this study, we try to isolate PNGase T gene from tomato, which can use as a platform plant for biotechnology industry. We isolated a cDNA (GenBank Accession number KM401550) from tomato leaves with 1,767 bp, which encoded a polypeptide of 588 amino acids with a predicted molecular mass of 65.8 kDa. We also investigated the expression patterns of PNGase T during fruit ripening of tomato. The transcripts of PNGase T, which were constitutively induced in tomato fruit from green stage, were significantly increased and reached a peak at orange stage. After which, those transcripts were continuously reduced. The expression pattern of PNGase T was coincided well with transcripts profiles of metacaspase gene, LeMCA, and senescence-related gene members of ACC synthase, LeACS2, LeACS4, and LeACS6, for ethylene biosynthesis during fruit ripening. These results suggest that PNGase T is involved in a de-glycosylation process associated with senescence and fruit ripening.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.293-297
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• 2012

Of the 169 strains of microorganisms stored in Polar and Alpine Microbial Collection of Korea Polar Research Institute, 27 strains were selected for their chitinase activity on ZoBell plates supplemented with 0.4% colloidal chitin. Among them, PAMC 21693 strain have shown the highest chitinolytic enzyme activity toward pNP-$(GlcNAc)_1$ at low temperature and the highest growth rate at $4^{\circ}C$. We cloned a full-length chitinase gene of 2,857 bp which contains an open reading frame of 2,169 bp encoding 872-amino acid polypeptide. Recombinant chitinase protein was expressed in E. coli and its molecular weight was confirmed 96 kDa. In this paper, we suggest the potential use of cold-active chitinase from polar microorganisms in the field of biotechnology.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.74-79
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• 2008

The purpose of this study is to clone cgt gene from Paenibacillus sp. JB-13 and to overexpress the protein in E. coli. For this purpose, the cgt gene was amplified from Paenibacillus sp. JB-13 genomic DNA by PCR using degenerate oligonucleotide primers. The sequence analysis results showed that the cgt gene from Paenibacillus sp. JB-13 has 98% homology with the cgt gene of Bacillus sp. To overexpress the protein, the cgt gene was cloned into pEXP7 expression vector and transformed into E. coli. The production of CGTase by recombinant E. coli was optimized under following conditions: 0.5% glucose, 3.0% polypeptone, 0.3% $K_2HPO_4$, 0.5% NaCl, and 7.0 of initial pH, 2.0% of inoculum, $37^{\circ}C$ of culture temperature for 14 hr. And the optimal agitation was found at 0.1 vvm. The synthesis of 2-O-${\alpha}$-D-Glucopyranosyl L-Ascorbic acid (AA-2G) using the CGTase expressed in E. coli was identified as AA-2G by HPLC and HPLC confirmed that treating AA-2G made by cloned CGTase with ${\alpha}$-glucosidase substantially produced AA and glucose.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.93-98
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• 2002

A VP6 fragments was subcloned with BamHI in the binary pMBP-1 vector under Califlower Mosaic Virus (CaMV) 355 promoter and neomycin phosphotransferase II (npt II) gene. The recombinant binary vector was mobilized into Agrobacterium-tumefaciens LBA4404 by the freeze-thaw method and potato (Solanum tubensum L. cv Desiree) was transformed by modified leaf-disc cocultivation. Shoots were induced on MS medium with 0.01 mg/L NAA, 0.1 mg/L GA$_3$, 2.0 mg/L Zeatin, 100.0 mg/L kanamycin, 500.0 mg/L carbenicillin. In order to identify the copy number of VP6 into potato plant, total genomic DNA was isolated from transgenic potato and analysed by Southern blotting. Genomic DNA and total mRNA analysis demonstrated the incorporation of the foreign gene into the potato genome, as well as their transcription.