• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1672-1677
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• 2008

IscR (iron-sulfur cluster regulator) has been reported to be a repressor of the iscRSUA operon, and in vitro transcription reactions have revealed that IscR has a repressive effect on the iscR promoter in the case of [$Fe_{2}S_{2}$] cluster loading. In the present study, the iscR gene from A. ferrooxidans ATCC 23270 was cloned and successfully expressed in Escherichia coli, and then purified by one-step affinity chromatography to homogeneity. The molecular mass of the IscR was 18 kDa by SDS-PAGE. The optical and EPR spectra results for the recombinant IscR confirmed that an iron-sulfur cluster was correctly inserted into the active site of the protein. However, no [$Fe_{2}S_{2}$] cluster was assembled in apoIscR with ferrous iron and sulfide in vitro. Therefore, the [$Fe_{2}S_{2}$] cluster assembly in IscR in vivo would appear to require scaffold proteins and follow the Isc "AUS" pathway.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.561-566
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• 2014

The complete coding sequence of Wild Argali ISG15 cDNA was generated by rapid amplification of cDNA ends. The ISG15 cDNA was 642 bp with an open reading frame of 474 bp, which encoded a 17.47 kDa protein composed of 157 amino acids. Its amino acid sequence shared 97.9%, 80.8%, 91.4%, 94.3%, 78.3% identity with those of ISG15cDNA from Ovis aries (accession no. NM001009735.1), Capra hircus (accession no. HQ329186.1), Bos taurus (accession no. BC102318.1), Bubalus bubalis (accession no. HM543269.1), and Sus scrofa (accession no. EU647216.1), respectively. The entire coding sequence was inserted into the pET-28a vector and expressed in E. coli. The recombinant protein corresponded to the expected molecular mass of 25 kDa as judged by SDS-PAGE, and it was detected in the bacterial inclusion bodies. The expressed protein could be purified by $Ni^{2+}$ chelate affinity chromatography and the results from the lymphocyte proliferation test showed that the product could stimulate lymphocyte proliferation very well (p<0.05), which further confirmed its biological activity.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.167-172
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• 2001

A cDNA fragment encoding the chloroplastic fructose-1, 6-bisphosphatase (FBPase) was cloned via PCR from the cDNA library of pea leaves. The cloned cDNA, about 1.05 kbp without signal sequence, was introduced into a pET-28a vector for expression in E. coli strain BL21(DE3)pLysS. The recombinant FBPase was purified through $Ni^+-NTA$ affinity chromatography and characterized. Molecular mass of the monomer was about 42,000. Enzymatic activity of the purified enzyme as the native pea chloroplastic FBPase was the highest at alkaline pH (pH 9.0). The recombinant enzyme was activated by a reducing agent DTT and was insensitive to AMP. The activation energy (Ea) and Arrehenius frequency factor were 42.67 kcal/mol and $2.65{\times}10^{14}/s$, respectively, slightly higher than those of the native enzyme. $K_M$ and $V_{max}$ were $99.98{\mu}M$ and $52.9{\mu}M/min$, respectively, which were comparable with the native enzyme.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1188-1192
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• 2003

In order to study the role of residue in the active site of glutathione S-transferase (GST), Tyr 108 residue in human GST P1-1 was replaced with alanine, phenylalanine and tryptophan by site-directed mutagenesis to obtain mutants Y108A, Y108F and Y108W. These three mutant enzymes were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized GSH. The substitutions of Tyr108 significantly affected $K_m^{CDNB}$ and $K_m^{ETA}$, whereas scarcely affected $K_m^{GSH}$. The substitutions of Tyr108 also significantly affected $I_{50}$ of ETA, an electrophilic substrate-like compound. The effect of these substitutions on kinetic parameters and the response to inhibition suggests that tyrosine 108 in hGST P1-1 contributes to the binding of the electrophilic substrate and a major determinant in the binding of CDNB is the aromatic ring of Tyr108, not its hydroxyl group.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.225-230
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• 2009

Lily mottle virus (LMoV) causes flower quality reduction in Lilium spp. The coat protein gene was RT-PCR-amplified from total RNA extracted from infected lily leaves and the amplified fragment was cloned into the pRSET expression vector tagged with a His-MBP. The plasmid of recombinant coat protein was used to transform an Escherichia coli strain pLysS and was expressed. The coat protein was purified by affinity chromatography using a Ni-NTA resin. The identity of the purified protein was confirmed by SDS-PAGE. The in vitro-expressed protein was used for immunization of mice. The polyclonal and monoclonal antibodies reacted specifically for the detection of LMoV in lily extracts in Western blot. Moreover the monoclonal antibodies reacted with lily extracts in DAS-ELISA with no unspecific or heterologous reactions against other non-serologically related viruses, but the polyclonal antibodies revealed a weak reaction against both infected lily and healthy control.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.459-462
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• 2001

Angiopoietin-2 (Ang2) is a naturally occurring antagonist for angiopoietin-l (Angl) and its Tie2 receptor during vasculogenesis, Although angiopoietins have been expressed in several mammalian cell lines, their expression levels are low. Recombinant Chinese hamster ovary (CHO) cell lines expressing a high level of human Ang2 or its analog, human $Ang2_{443}$, with an amino-terminal FLAG-tag were constructed by transfecting the expression vectors into dhfr-deficient CHO cells and subsequent gene amplification in medium containing stepwise increments in methotrexate level. Secreted Ang2 or human $Ang2_{443}$ were purified from the cultured medium using an anti-FLAG- agarose affinity chromatography, The purified Ang2 and $Ang2_{443}$ migrated on SOS-PAGE as a broad band, characteristic of glycosylated protein. Their biological activity in vitro was demonstrated in a serum deprivation-induced apoptosis assay. Ang2 at high concentration, like AngI, can be an apoptosis survival factor for endothelial cells through the activation of the Tie2 receptor.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.550-553
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• 2003

The genes of GFPuv and Cytochrome c-552 were amplified by using PCR, and then, fused each other. Fusion gene of GFPuv and Cytochrome c-552 was inserted into the pTrcHis B vector and transferred to E. coli. A fusion protein of GFPuv and Cytochrome c-552 was expressed in JM109 and BL21. This fusion protein was composed of a His-tag for the rapid one-step purification using an immobilized metal affinity chromatography.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.554-556
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• 2003

This research was focused on expression, purification and characterization of ubiquitin-specific protease 1 (UBP1) expressed in recombinant Escherichia coli. Various systems were constructed by fusing polycationic fusion tails or fusion partners to the C- or N-terminus of the product protein. In particular, UBP1 containing 6 histidine residues at the N-terminal end showed best results in terms of expression level and purification efficiency. The N-terminal $6{\times}His-tagged$ UBP1 was overproduced in recombinant E. coli using high cell density cultivation technology and purified using immobilized metal affinity chromatography. The molecular weight of UBP1 was found to be 83,500 daltons. The optimum temperature and pH for the enzyme reaction when ubiquitin-human growth hormone (hGH) was used as a substrate were $40^{\circ}C$ and pH 8.0, respectively.

• KSBB Journal
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• v.30 no.6
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• pp.296-301
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• 2015

Eggshell-based biocomposites have become attractive due to their exquisite nanostructure and biological properties, which are mainly composed of highly organized calcium carbonate crystals controlled by organic macromolecules such as proteins and polysaccharides. Here, we designed the recombinant fusion protein of a putative eggshell matrix protein named as GG1234 and a fluorescent reporter protein of DsRed. The protein was successfully over-expressed in E. coli and purified by Ni-NTA affinity chromatography. In vitro calcium carbonate crystallization was conducted in the presence of the fusion protein, and morphological change was investigated. The protein inhibited the calcite growth in vitro, and spherical calcium carbonate micro-particles with the diameter of about $20-30{\mu}m$ were obtained. We expect that this study would be helpful for better understanding of eggshell-based biomineralization.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.964-972
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• 1994

The 4.3-kb gene coding for L-lactate dehydrogenase of Bacillus stearothermophilus has been subcloned and expressed in E. coli cells. The enzyme was purified 200-fold with 25% yield by heat treatment , DEAE-Sephadex, and NAD++ -Sepharose CL-4B affinity chromatography followed by gel filtration through Sephadex G-200 . The molecular weight of the purfied enzyme was estimated to be about 35, 000 and 140, 000 on SDS-polyacrylamide gel electrophoresis and gel filtration, respectively. indicating that the enzyme is composed of four identical subunits. THe enzyme for pyruvate reduction and lactate oxdiation was stable at 60 and 75$^{\circ}C$ for 30 min, and the optimal temperatures for both reactions were 60 and 7$0^{\circ}C$, respectively. The enzyme had an optimal pH at 5.5 and 8.5 in pyruvate reduction and lactate oxidation, respectively. The pH stability of enzyme of pyruvate reduction was table between pH 5 and 7. more than 90% of enzyme activity was lost at 1mM FeSO4 and p-chloromercuribonzoate. The maximal activation of the enzyme was obtained with 0.8mM fructose 1, 6-bisphosphate.