• BMB Reports
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• 제56권11호
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• pp.606-611
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• 2023

The main protease (Mpro) of SARS-CoV-2 cleaves 11 sites of viral polypeptide chains and generates essential non-structural proteins for viral replication. Mpro is an important drug target against COVID-19. In this study, we developed a real-time fluorometric turn-on assay system to evaluate Mpro proteolytic activity for a substrate peptide between NSP4 and NSP5. It produced reproducible and reliable results suitable for HTS inhibitor assays. Thus far, most inhibitors against Mpro target the active site for substrate binding. Mpro exists as a dimer, which is essential for its activity. We investigated the potential of the Mpro dimer interface to act as a drug target. The dimer interface is formed of domain II and domain III of each protomer, in which N-terminal ten amino acids of the domain I are bound in the middle as a sandwich. The N-terminal part provides approximately 39% of the dimer interface between two protomers. In the real-time fluorometric turn-on assay system, peptides of the N-terminal ten amino acids, N10, can inhibit the Mpro activity. The dimer interface could be a prospective drug target against Mpro. The N-terminal sequence can help develop a potential inhibitor.

• Tuberculosis and Respiratory Diseases
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• 제70권1호
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• pp.21-27
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• 2011

Background: Although the gold standard method for research trials on epidermal growth factor receptor (EGFR) mutations has been direct sequencing, this approach has the limitations of low sensitivity and of being time-consuming. Peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping is known to be a more sensitive detection tool. The aim of this study was to compare the detection rate of $EGFR$ mutation and EGFR-tyrosine kinase inhibitor (TKI) responsiveness according to $EGFR$ mutation status using both methodologies. Methods: Clinical specimens from 112 NSCLC patients were analyzed for $EGFR$ mutations in exons 18, 19, 20, and 21. All clinical data and tumor specimens were obtained from 3 university hospitals in Korea. After genomic DNA was extracted from paraffin-embedded tissue specimens, both PNA-mediated PCR clamping and direct-sequencing were performed. The results and clinical response to $EGFR$-TKIs were compared. Results: Sequencing revealed a total of 35 (22.9%) mutations: 8 missense mutations in exon 21 and 26 deletion mutations in exon 19. PNA-mediated PCR clamping showed the presence of genomic alterations in 45 (28.3%) samples, including the 32 identified by sequencing plus 13 additional samples (6 in exon 19 and 7 in exon 21). Conclusion: PNA-mediated PCR clamping is simple and rapid, as well as a more sensitive method for screening of genomic alterations in $EGFR$ gene compared to direct sequencing. This data suggests that PNA-mediated PCR clamping should be implemented as a useful screening tool for detection of $EGFR$ mutations in clinical setting.

• 생명과학회지
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• 제13권4호
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• pp.541-550
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• 2003

본 실험에서는 C형 간염바이러스 (HCV)의 외피 단백질인 E2 당단백질에 결합하는 세포단백질들을 클로닝하기 위해 간세포 cDNA를 phage 표면에 발현시킨 phage library를 제작하였고, 12-mer peptide library와 함께 E2 단백질에 대해 panning을 실시하였다. 검색결과 세포내 신호전달과 cytoskeleton 구성에 관여하는 tensin, membrane protein band 4.1 등 세포질내 단백질과 CCR7, CKR-L2, insulin-like growth factor-1 receptor 등 세포막 단백질 등이 확인되었다. 이들 단백질들을 발현하는 phage들은 수용성 E2단백질을 이용한 결합중화반응 결과 E2 단백질에 특이적으로 결합함이 확인되었다. 사람 T 세포에서 주로 발현되는 CCR7 유전자를 PHA로 활성화된 사람 T 세포의 total RNA를 이용하여 증폭하고 클로닝하였다. 293T 세포에 transfection시켜 단백질 발현양상을 flow cytometer로 분석하여 70% 이상의 세포들이 CCR7을 발현하고 있음을 관찰하였다. 수용성 E2 단백질을 CCR7이 transfection된 세포와 mock transfection된 대조군 세포에 각각 반응시킨 결과 dose-dependent 양상으로 CCR7에 결합하였다.

• Journal of Oral Medicine and Pain
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• 제24권2호
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• pp.181-187
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• 1999

The most important progress in diagnostic sciences is the increased sensitivity and specificity in diagnostic procedures due to the development of newer micromethodologies and increasing availability of immunological and molecular biological reagents. The outcome of researches in this field has already provided DNA probes and antibodies which can be used for diagnosing various kinds of diseases including inherited ones. This development can be also applied to diagnose diseases in oral and maxillofacial regions. Technological advances have yielded highly sensitive test methodologies so that low analyte concentration and small sample volume are no longer limiting factors. Therefore, saliva can be useful test fluid for an array of analytes. Salivary constituents of diagnostic significance include steroid hormones, antibodies, drugs, and tumor markers. Of the proteins present in saliva, viral-specific immunoglobulins are of the greatest diagnostic interest. The development of conjugates and antigens by recombinant DNA technique and peptide synthesis is necessary for clinical application. Several kits developed for the purpose of blood testing should be modified to permit their application to saliva. The final practical outcome of researches in diagnostic sciences will be various diagnostic agents which can be used for detection of bacteria and viruses, screening and diagnosis of diseases, genetic screening for forensic individual identification. For these purposes, collaboration researches and development between institutions and companies are essential.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.600-606
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• 2012

Studies into the cell death program termed apoptosis have resulted in new information regarding how cells control and execute their own demise, including insights into the mechanism by which death-preventing factors can inhibit Bax-induced caspase activation. We investigated high temperature stress-induced cell death in Brassica rapa. Using a yeast functional screening from a Brassica rapa cDNA library, the BH5-127 EST clone encoding an apoptotic suppressor peptide was identified. However, a phylogenic tree showed that BH5-127 clusters within a clade containing SUMO-1 (Small Ubiquitin-like Modifier-1). BH5-127 was confirmed similar to have function to SUMO-1 as Fas suppression. Expression of BH5-127 showed that substantial suppression of cell death survived on SD-galactose-$Leu^-$-$Ura^-$ medium. The results suggest that BrSE ($\underline{B}$rassica rapa $\underline{S}$entrin $\underline{E}$ST, BH5-127) is one of the important regulatory proteins in programming cell death, especially in the seedling stage of Chinese cabbage.

• 한국잠사곤충학회지
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• 제38권1호
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• pp.19-24
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• 1996

누에에서 생체 방어에 관련된 새로운 항 세균성 펩타이드 유전자를 탐색 분리하기 위하여 누에 체강에 비 병원성 세균인 Escherichia coli를 주사하여 면역 반응의 일환으로 발현량이 증가하는 유도 유전자 종류를 조사 하였다. 체강 주사 8시간 후 누에에서 cDNA 유전자 은행을 만들고, 정상 및 유도 누에에서 분리한 각각의 mRNA를 탐침으로 차별화 선별을 하였다. 차별화 선별 결과 정상보다도 유도 누에의 탐침을 사용한 막에서 강도가 높은 클론 32개를 선발하였고, 29개 클론에 대해 전체 또는 부분 염기 서열을 분석하여 DNA 상동성을 조사하였다. DNA 상동성 비교를 통해 생산한 발현 유전자 꼬리표 중에는 비교적 상동 유의성이 인정되어 그 실체를 추정할 수 있는 19개의 클론이 있었다. 특히 곤충의 면역 작용에 직접적으로 관계하는 항세균성 펩타이드 유전자, hemolin 유전자, transferrin 유전자 등 4종의 유전 자원을 확보할 수 있었다.

• 한국식품영양과학회지
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• 제25권2호
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• pp.193-198
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• 1996

담즙산과 결합을 하여 콜레스테롤 농도에 영향을 주는 것으로 보고된 대두 단백질의 생체내 효소에 의한 미분해성 분획물 개량 메주로부터 분리하였다. 개량 메주로부터 pH 6.8 과 pH 4.5의 분획물들을 분리하여, 초음파 처리와 투석을 행한 후 Sephadex G-75 column chromatography를 실시하여 부분 정제하였다. 부분 정제된 분획물들을 chemiluminescence 방법에 의해 in vitro에서 검색을 한 결과, pH 4.5 분획물중의 하나가 담즙산과 강하게 결합하는 것으로 밝혀졌다. 또한 대두 기원의 pepsin 비분해성 분획물 또한 pH 4.5 분획물의 chemiluminescence 결과와 일치하였다. 따라서 본 연구에서 고안한 chemiluminescence 법은 in vitro에서 담즙산 결합 활성도 측정 및 콜레스테롤 대사에 관한 연구의 기본적인 연구 수단을 평가되며 따라서 본 연구 결과는 이 분야의 연구에 기초 자료로 제공될 수 있는 가능성을 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1717-1720
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• 2007

In the course of screening for nitric oxide inhibitors in activated microglial BV-2 cells, cyclo(dehydrohistidyl-L-tryptophyl) was isolated from solid-state fermentation cultures of an unidentified fungal strain, Fb956. Its structure was determined by spectroscopic methods including 2D NMR and chiral TLC analyses. Cyclo(dehydrohistidyl-L-tryptophyl) was found to have an inhibitory activity on nitric oxide production with an $IC_{50}$ of $6.5\;{\mu}M$ in activated BV-2 cells. The structure determination and biological activity of cyclo(dehydrohistidyl-L-tryptophyl) was reported for the first time in this study.

• Animal cells and systems
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• 제12권1호
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• pp.35-39
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• 2008

Menadione induced cell death in cultured C2 myoblasts. By screening synthetic peptide libraries composed of random sequence of hexapeptides, we identified the hexa-peptides pool of(Ala/Ile)-(Ile/Met)-Val-Ile-Asp-(Met/Ser)-$NH_2$ that protected the myoblasts against menadioneinduced cell death. Pre-incubation with the hexapeptide pool reduced the number of cells detached from culture dish substrate and increased the ratio of relative viability against menadione. In addition, the peptides strongly increased the expression of Bcl-2, an anti-apoptotic protein. These results suggest that the hexapeptides might enhance the resistance to cell death against menadione by increasing the expression of Bcl-2.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1468-1471
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• 2006

The last step in L-carnitine biosynthesis in eukaryotic organisms is mediated by ${\gamma}$-butyrobetaine hydroxylase (EC1.14.11.1), a dioxygenase that converts ${\gamma}$-butyrobetaine to L-carnitine. This enzyme was previously identified from rat liver and humans, and the peptide sequence of human ${\gamma}$-butyrobetaine hydroxylase was used to search the Neurospora crassa genome database, which led to an identification of an open reading frame (ORF) consisting of 1,407 bp encoding a polypeptide of 468 amino acids. When this protein was expressed in Saccharomyces cerevisiae, the crude cell-free extract exhibited ${\gamma}$-butyrobetaine hydroxylase activity.