• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1097-1103
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• 2020

Bacterial surface display systems have been developed for various applications in biotechnology and industry. Particularly, the discovery and design of anchoring motifs is highly important for the successful display of a target protein or peptide on the surface of bacteria. In this study, an efficient display system on Escherichia coli was developed using novel anchoring motifs designed from the E. coli mipA gene. Using the C-terminal fusion system of an industrial enzyme, Pseudomonas fluorescens lipase, six possible fusion sites, V¹⁴⁰, V¹⁷⁶, K¹⁷⁹, V²²⁶, V²³², and K²³⁴, which were truncated from the C-terminal end of the mipA gene (MV¹⁴⁰, MV¹⁷⁶, MV¹⁷⁹, MV²²⁶, MV²³², and MV²³⁴) were examined. The whole-cell lipase activities showed that MV¹⁴⁰ was the best among the six anchoring motifs. Furthermore, the lipase activity obtained using MV¹⁴⁰ as the anchoring motif was approximately 20-fold higher than that of the previous anchoring motifs FadL and OprF but slightly higher than that of YiaTR232. Western blotting and confocal microscopy further confirmed the localization of the fusion lipase displayed on the E. coli surface using the truncated MV¹⁴⁰. Additionally the MV¹⁴⁰ motif could be used for successfully displaying another industrial enzyme, α-amylase from Bacillus subtilis. These results showed that the fusion proteins using the MV¹⁴⁰ motif had notably high enzyme activities and did not exert any adverse effects on either cell growth or outer membrane integrity. Thus, this study shows that MipA can be used as a novel anchoring motif for more efficient bacterial surface display in the biotechnological and industrial fields.

• IMMUNE NETWORK
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• v.3 no.2
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• pp.126-135
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• 2003

Background: One of the important factors in the prognosis of chronic hepatitis B patient is the degree of replication of hepatitis B virus (HBV). It has been known that HBV DNA polymerase plays the essential role in the replication of HBV. HBV DNA polymerase is composed of four domains, TP (Terminal protein), spacer, RT (Reverse transcriptase) and RNaseH. Among these domains, tyrosine, the $65^{th}$ residue of TP is an important residue in protein-priming reaction that initiates reverse transcription. If monoclonal antibody that recognizes around tyrosine residue were selected, it could be applied to further study of HBV replication. Methods: To produce TP-specific scFv (single-chain Fv) by phage display, mice were immunized using synthetic TP-peptide contains $57{\sim}80^{th}$ amino acid residues of TP domain. After isolation of mRNA of heavy-variable region ($V_H$) and light-chain variable region ($V_L$) from the spleen of the immunized mouse, DNA of $V_H$ and $V_L$ were obtained by RT-PCR and joined by a DNA linker encoding peptide (Gly4Ser)3 as a scFv DNA fragments. ScFv DNA fragments were cloned into a phagemid vector. scFv was expressed in E.coli TG1 as a fusion protein with E tag and phage gIII. To select the scFv that has specific affinity to TP-peptide from the phage-antibody library, we used two cycles of panning and colony lift assay. Results: The TP-peptide-specific scFv was isolated by selection process using TP-peptide as an antigen. Selected scFv had 30 kDa of protein size and its nucleotide sequences were analyzed. Indirect- and competitive-ELISA revealed that the selected scFv specifically recognized both TP-peptide and the HBV DNA polymerase. Conclusion: The scFv that recognizes the TP domain of the HBV DNA polymerase was isolated by phage display.

• Journal of Life Science
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• v.24 no.9
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• pp.995-1000
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• 2014

The studies of marine viruses in terms of viral isolation and detection have been limited due to the high mutation rate and genetic diversity of marine viruses. Of the modern methods currently used to detect marine viruses, serological methods based on enzyme-linked immunosorbent assay (ELISA) are the most common. They depend largely on the quality of the antibodies and on highly purified suitable antigens. Recently, a new experimental system for using viral capsid protein as an antigen has been developed using the yeast surface display (YSD) technique. In the present study, the capsid protein gene of the red-spotted grouper nervous necrosis virus (RGNNV) was expressed and purified via YSD and HA-tagging systems, respectively. Two regions of the RGNNV capsid protein gene, RGNNV1 and RGNNV2, were individually synthesized and subcloned into a yeast expression vector, pCTCON. The expressions of each RGNNV capsid protein in the Saccharomyces cerevisiae strain EBY100 were indirectly detected by flow cytometry with fluorescently labeled antibodies, while recognizing the C-terminal c-myc tags encoded by the display vector. The expressed RGNNV capsid proteins were isolated from the yeast surface through the cleavage of the disulfide bond between the Aga1 and Aga2 proteins after ${\beta}$-mercaptoethanol treatment, and they were directly detected by Western blot using anti-HA antibody. These results indicated that YSD and HA-tagging systems could be applicable to the expressions and purification of recombinant RGNNV capsid proteins.

• BMB Reports
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• v.30 no.5
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• pp.352-355
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• 1997

The surface adsorbed protein conformations onto the vaccine adjuvants were observed with a Raman spectroscopy by using the maximum adsorption conditions described previously. The adsorbed state Raman vibrational spectra and subsequent spectral analysis display no conformational changes for BSA or IgG relative to their native species in solution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5412-5418
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• 2014

The red seabream iridovirus (RSIV), which belongs to the iridoviridae, causes infectious fish diseases in many Asian countries, leading to considerable economic losses to the aquaculture industry. Using the yeast surface display (YSD) technique, a new experimental system was recently developed for the detection and identification of a variety of marine viruses. In this study, a coat protein gene of RSIV was synthesized based on the nucleotide sequence database and subcloned into the yeast expression vector, pCTCON2. The expression of viral coat proteins in the yeast strain, EBY100, was detected by flow cytometry and Western blot analysis. Finally, they were isolated from the yeast surface through a treatment with ${\beta}$-mercaptoethanol. The data suggests that the YSD system can be a useful method for acquiring coating proteins of marine viruses.

• Toxicological Research
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• v.25 no.1
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• pp.35-40
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• 2009

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and related halogenated aromatic hydrocarbons elicit a diverse spectrum of biochemical and toxic responses in laboratory animals and mammalian cells in culture. Toxicity and carcinogenicity of TCDD is well established but the molecular mechanism is still poorly understood. Here, we found the noble responsive genes to TCDD using the differential display analysis. Treatment of HepG2 cells with TCDD showed a significantly different mRNA expression pattern from the untreated cells in differential display analysis. The differentially displayed bands were isolated and used as probes in dot blot and Northern blot analyses. Of thirty-five isolated differentially displayed bands, only two bands were confirmed as positive in dot blot and Northern blot analyses. The nucleotides sequences of these clones were analyzed and the search of Genebank database revealed that one clone is highly homologous with RanBP2 (Ras-related nuclear protein binding protein2; 92%) and the other is an unknown gene. RanBP2 is a nucleoporin with SUMO E3 ligase activity that functions in both nucleocytoplasmic transport and mitosis and its role as a novel tumor suppressor has been recently proposed. Thus, these results may suggest the clue elucidating the toxic mechanism of TCDD through RanBP2.

• Journal of Microbiology and Biotechnology
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• v.29 no.2
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• pp.179-190
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• 2019

Bacillus subtilis spore surface display (BSSD) technology is considered to be one of the most promising approaches for expressing heterologous proteins with high activity and stability. Currently, this technology is used for various purposes, such as the production of enzymes, oral vaccines, drugs and multimeric proteins, and the control of environmental pollution. This paper presents an overview of the latest developments in BSSD technology and its application in protein engineering. Finally, the major limitations of this technology and future directions for its research are discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.223-228
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• 2008

A novel beetle antimicrobial protein from stimulated Copris tripartitus and the corresponding gene were isolated in parallel through differential display-PCR and expression in Escherichia coli. To find cDNA clones responsible for bacteria resistance, the suppression subtractive hybridization and GeneFishing differentially expressed genes system were employed in the dung beetle, Copris tripartitus immunized with lipopolysaccaride. One cDNA clone from eight subtracted clones was selected through dot blot analysis and confirmed by northern blot analysis. The 516-bp, selected cDNA clone was determined by 5' and 3' rapid amplication of cDNA ends and cloned into the GST fusion expression vector pGEX-4T-1 for expression of the protein. The expressed protein was predicted 14.7 kDa and inhibited the growth of gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. These results implied that the expressed protein is related to immune defense mechanism against microorganism.

• KSBB Journal
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• v.26 no.3
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• pp.243-247
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• 2011

Using Bacillus subtilis spore display system, with cotG as an anchoring motif, levansucrase from Zymomonas mobilis, was displayed on the outer surface of Bacillus subtilis spore. Flow cytometry of DB104 (pSDJH-cotG-levU) spore, proved the surface localization of CotG-LevU fusion protein on the spore compared to that of DB104. Enzymatic activity of DB104 (pSDJH-cotG-levU) spore showed more than 1.5 times higher levansucrase specific activity compared to that of the host spore, which is a remarkable increase of enzymatic activity considering the existence of sacA (sucrase) and sacB (levansucrase) in the Bacillus subtilis chromosome. The spore integrity, revealed by sporulation frequency test after heat and lysozyme treatment of spore, did not changed at all in spite of the CotG-LevU fusion protein incorporation into the spore coat layer during spore formation process. These data prove again that Bacillus subtilis spore could be considered as good live immobilization vehicle for efficient bioconversion process.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.199-205
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• 2019

Yeast two-hybrid (Y2H) technique has been used to study protein-protein interactions, but its application particularly to a large-scale analysis of protein interaction networks, is limited by the fact that the technique is labor-intensive, based on scoring colonies on plate. Here, we develop a new reporter for the measurement of the protein-protein interactions by flow cytometry. The yeast harboring interacting proteins can also be enriched by fluorescence-activated cell sorting (FACS) or magnetic-activated cell sorting (MACS). When two interacting proteins are present in the same yeast cell, a reporter protein containing 10 tandem repeats of c-myc epitope becomes localized on the surface of the cell wall, without affecting cell growth. We successful measured the surface display of c-myc epitope upon interacting p53 with SV40 T antigen by flow cytometry. Thus, the newly developed Y2H assay based on the display of c-myc repeat on yeast cell wall could be used to the simultaneous analysis of multiple protein-protein interactions without laborious counting colonies on plate.