• BMB Reports
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• v.32 no.2
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• pp.181-188
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• 1999

4-Aminobutyrate aminotransferase plays an essential role in the 4-aminobutyric acid shunt, converting 4-aminobutyrate to succinic semialdehyde. Recombinant 4-aminobutyrate aminotransferases were overexpressed as their catalytically active forms in E. coli by coproduction with thioredoxin and their solubilities were also dramatically increased. In order to study the structural and functional aspects of the C-terminal domain of brain 4-aminobutyrate aminotransferase, we have constructed a C-terminal mutant of pig brain 4-aminobutyrate aminotransferase and analyzed the functional and structural roles of C-terminal amino acids residues on the enzyme. The deletion of five amino-acid residues from C-terminus did not interfere with the kinetic parameters and functional properties of the enzyme. Also, the deletion did not affect the dimeric structure of the protein aligned along the subunit interface at neutral pH. However, the deletion of the C-terminal region of the protein changed the stability of its dimeric structure at acidic pH. The dissociation of the enzyme acidic, facilitated by the deletion of five amino acids from C-terminus, abolished the catalytic activity.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.137-141
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• 2008

We previously isolated and cloned a cDNA of abaecin from the Bombus ignitus. In an effort to produce a large amount of soluble abaecin at low cost, we successfully expressed the peptide in Escherichia coli that are highly sensitive to its mature form. For this, we fused the peptide encoding 39 amino acids of mature B. ignitus abaecin to the thioredoxin gene together with a C-terminal 6xHis tag. An enterokinase cleavage site was introduced between the 6xHis tag and mature abaecin to allow final release of the recombinant peptide. A high yield of 9.6 mg soluble fusion protein from 200 ml of bacterial culture was purified by $Ni^{2+}$-charged His-Bind resin affinity column, and 1.4 mg of pure active recombinant abaecin was readily obtained by enterokinase cleavage, followed by affinity chromatograph. The molecular mass of recombinant abaecin peptide was determined by Tricin-SDS-PAGE analysis. The recombinant abaecin exhibited antibacterial activity against Gram-negative bacteria.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.1
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• pp.15-20
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• 2018

Most proteins produced in the endoplasmic reticulum (ER) of eukaryotic cells fold via disulfide formation (oxidative folding). Oxidative folding is catalyzed by protein disulfide isomerase (PDI) and PDI-related ER protein thiol disulfide oxidoreductases (ER oxidoreductases). In yeast and mammals, ER oxidoreductin-1s (ERO1s) supply oxidizing equivalent to the active centers of PDI. We previously identified and characterized the ERO1 of Bombyx mori (bERO1) as a thioredoxin-like protein that shares primary sequence homology with other ERO1s. Here we compare the reactivation of inactivated rRNase and sRNase by bERO1, and show that bERO1 and bPDI cooperatively refold denatured RNase A. This is the first result suggesting that bERO1 plays an essential role in ER quality control through the combined activities of bERO1 and bPDI as a catalyst of protein folding in the ER and sustaining cellular redox homeostasis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.243-247
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• 2016

Arsenic (As) is a toxic element that easily taken up by plants root. Several toxic forms of As disrupt plant metabolism by a series of cellular alterations. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in alfalfa roots in response to As stress. Two-week-old alfalfa seedlings were exposed to As treatment for 6 hours. DEGs were screened from As treated samples using the ACP-based technique. A total of six DEGs including heat shock protein, HSP 23, plastocyanin-like domain protein162, thioredoxin H-type 1 protein, protein MKS1, and NAD(P)H dehydrogenase B2 were identified in alfalfa roots under As stress. These genes have putative functions in abiotic stress homeostasis, antioxidant activity, and plant defense. These identified genes would be useful to increase As tolerance in alfalfa plants.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.530-533
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• 2002

This paper describes the development of an enzymatic assay system for the identification of specific inhibitors of sortase, a transpeptidase that cleaves surface proteins of Cram-positive bacteria, from Staphylococcus aureus ATCC 6538p for antibacterial drug discovery. The coding region of the enzyme was amplified with the exception of the N-terminal membrane anchor sequence, cloned into a vector providing His-Patch-thioredoxin-tag at the N-terminus, expressed in Escherichia coli, and purified by metal chelate affinity chromatography. The enzyme activity was determined by quantifying increased fluorescence intensity upon cleavage of synthetic Dabcyl-QALPETGEE-Edans peptide. The results suggest that the developed in vitro assay system call be used in the search for sortase inhibitors In a short period of time.

• BMB Reports
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• v.42 no.6
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• pp.367-372
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• 2009

In this study, we showed that WAX9D, a nonspecific lipid-transfer protein found in broccoli, binds palmitate (C16) and stearate (C18) with dissociation constants of 0.56 ${\mu}M$ and 0.52 ${\mu}M$, respectively. WAX9D was fused to thioredoxin protein by genetic manipulation to enhance its solubility. The data revealed strong interaction of Trx-WAX9D with palmitate and stearate. The dissociation constants of Trx-WAX9D for palmitate and stearate were 1.1 ${\mu}M$ and 6.4 ${\mu}M$, respectively. The calculated number of binding sites for palmitate and stearate was 2.5 to 2.7, indicating that Trx-WAX9D can bind three molecules of fatty acids. Additionally, Trx-WAX9D was shown to inhibit the apoptotic effect of palmitate in endothelial cells. Our data using Trx-WAX9D provide insight into the broad spectrum of its biological applications with specific palmitate binding.

• BMB Reports
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• v.50 no.9
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• pp.466-471
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• 2017

The results of this study show that c-Jun N-terminal kinase (JNK) activation was associated with the enhancement of docetaxel-induced cytotoxicity by simvastatin in DU145 human prostate cancer cells. To better understand the basic molecular mechanisms, we investigated simvastatin-regulated targets during simvastatin-induced cell death in DU145 cells using two-dimensional (2D) proteomic analysis. Thus, vimentin, Ras-related protein Rab-1B (RAB1B), cytoplasmic hydroxymethylglutaryl-CoA synthase (cHMGCS), thioredoxin domain-containing protein 5 (TXNDC5), heterogeneous nuclear ribonucleoprotein K (hnRNP K), N-myc downstream-regulated gene 1 (NDRG1), and isopentenyl-diphosphate Delta-isomerase 1 (IDI1) protein spots were identified as simvastatin-regulated targets involved in DU145 cell death signaling pathways. Moreover, the JNK inhibitor SP600125 significantly inhibited the upregulation of NDRG1 and IDI protein levels by combination treatment of docetaxel and simvastatin. These results suggest that NDRG1 and IDI could at least play an important role in DU145 cell death signaling as simvastatinregulated targets associated with JNK activation.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.34-44
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• 2003

Objective : Bone homeostasis is maintained by balance of bone formation and resorption. Therefore, bone related diseases arose by disturbance of this balance between osteoblast and osteoclast activities. To develop a successful screening system the therapeutic components based on oriental medicine is essential to set up systematic approach for that purpose. The purpose of this study is to the know the gene expression using cDNA microarray assay. Methods : Cervi Pantotricuhum Cornu Herbal-acupuncture extract was prepared by boiling. human osteosarcoma cells(HOS) were treated with Cervi Pantotricuhum Cornu Herbal-acupuncture solution. Then mRNA was extracted and cDNA microarray assay was performed. Results : Human osteosarcoma cells(HOS) treated with Cervi Pantotricuhum Cornu Herbal-acupuncture solution($500{\mu}g/m{\ell}$) showed that thioredoxin, TAFII31 and two novel genes were increased. However many genes decreased their expression by Cervi Pantotricuhum Cornu Herbal-acupuncture. Conclusions : This type of approach will give a good chance to explore the favorable effects of Cervi Pantotricuhum Cornu Herbal-acupuncture. Further study is needed for investigating the effect of Cervi Pantotricuhum Cornu Herbal-acupuncture.

• Molecules and Cells
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• v.23 no.2
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• pp.252-257
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• 2007

Escherichia coli HslVU is an ATP-dependent protease consisting of two heat shock proteins, the HslU ATPase and HslV peptidase. In the reconstituted enzyme, HslU stimulates the proteolytic activity of HslV by one to two orders of magnitude, while HslV increases the rate of ATP hydrolysis by HslU several-fold. Here we show that HslV alone can efficiently degrade certain unfolded proteins, such as unfolded lactalbumin and lysozyme prepared by complete reduction of disulfide bonds, but not their native forms. Furthermore, HslV alone cleaved a lactalbumin fragment sandwiched by two thioredoxin molecules, indicating that it can hydrolyze the internal peptide bonds of lactalbumin. Surprisingly, ATP inhibited the degradation of unfolded proteins by HslV. This inhibitory effect of ATP was markedly diminished by substitution of the Arg86 residue located in the apical pore of HslV with Gly, suggesting that interaction of ATP with the Arg residue blocks access of unfolded proteins to the proteolytic chamber of HslV. These results suggest that uncomplexed HslV is inactive under normal conditions, but may can degrade unfolded proteins when the ATP level is low, as it is during carbon starvation.

• Molecules and Cells
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• v.26 no.3
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• pp.228-235
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• 2008

Thiol-dependent redox systems are involved in regulation of diverse biological processes, such as response to stress, signal transduction, and protein folding. The thiol-based redox control is provided by mechanistically similar, but structurally distinct families of enzymes known as thiol oxidoreductases. Many such enzymes have been characterized, but identities and functions of the entire sets of thiol oxidoreductases in organisms are not known. Extreme sequence and structural divergence makes identification of these proteins difficult. Thiol oxidoreductases contain a redox-active cysteine residue, or its functional analog selenocysteine, in their active sites. Here, we describe computational methods for in silico prediction of thiol oxidoreductases in nucleotide and protein sequence databases and identification of their redox-active cysteines. We discuss different functional categories of cysteine residues, describe methods for discrimination between catalytic and noncatalytic and between redox and non-redox cysteine residues and highlight unique properties of the redox-active cysteines based on evolutionary conservation, secondary and three-dimensional structures, and sporadic replacement of cysteines with catalytically superior selenocysteine residues.