• 생명과학회지
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• 제22권8호
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• pp.1024-1033
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• 2012

Kocuria gwangalliensis로부터 카로티노이드 생합성 경로의 첫 번째 단계 기질인 geranylgeranyl pyrophosphate (GGPP)를 생합성하는 GGPP synthase (CrtE)를 암호화하고 있는 crtE를 클로닝 하여 이를 KgGGPP로 명명하였다. 기존 세균에서 밝혀진 GGPP synthase의 아미노산 서열을 NCBI에서 검색하여 KgGGPP synthase의 아미노산 서열과 비교한 결과 Kocuria rhizophila와 59.6%의 상동성을 가지는 것을 확인하였다. crtE 유전자를 대장균에서 발현 시키기 위하여 pCcrtE 재조합 DNA를 구축하였고, 이를 대장균에서 발현시킨 결과 약 41 kDa의 재조합 단백질이 과발현 됨을 확인 할 수 있었으며, 이 단백질은 기존 세균에서 밝혀진 GGPP synthase와 유사한 분자량을 가지고 있다는 것을 알 수 있었다. CrtE 재조합 단백질의 활성을 분석하기 위하여 대장균 내에서 라이코펜의 생합성을 유도 하였다. 대장균의 경우 메발론산 경로를 통하여 FPP와 IPP를 생합성 하지만 crtE, crtB, crtI 유전자가 없기 때문에 라이코펜을 생합성 하지는 못한다. 대장균 내에서 라이코펜의 생합성을 위해서는 crtE, crtB, crtI 유전자의 발현이 필수적으로 요구되기 때문에 crtB, crtI 유전자의 경우는 P. haeundaensis에서 유래한 유전자를 이용하여 pRScrtBI 재조합 DNA를 구축하여 그 발현을 유도하였다. 상기 두 재조합 DNA를 대장균에서 공발현 시켰으며, HPLC 분석법을 이용하여 대장균 내에서 라이코펜의 생산 유무에 따른 KgGGPP synthase의 활성을 분석하였다.

• Molecules and Cells
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• 제38권4호
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• pp.373-379
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• 2015

Pyruvate kinase M2 isoform (PKM2), a rate-limiting enzyme in the final step of glycolysis, is known to be associated with the metabolic rewiring of cancer cells, and considered an important cancer therapeutic target. Herein, we report a novel PKM2 activator, PA-12, which was identified via the molecular docking-based virtual screening. We demonstrate that PA-12 stimulates the pyruvate kinase activity of recombinant PKM2 in vitro, with a half-maximal activity concentration of $4.92{\mu}M$, and effectively suppresses both anchorage-dependent and -independent growth of lung cancer cells in non-essential amino acid-depleted medium. In addition, PA-12 blocked the nuclear translocalization of PKM2 in lung cancer cells, resulting in the inhibition of hypoxia response element (HRE)-mediated reporter activity as well as hypoxia-inducible factor 1 (HIF-1) target gene expression, eventually leading to the suppression of cell viability under hypoxia. We also verified that the effects of PA-12 were dependent on PKM2 expression in cancer cells, demonstrating the specificity of PA-12 for PKM2 protein. Taken together, our data suggest that PA-12 is a novel and potent PKM2 activator that has therapeutic implications for lung cancer.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.292-300
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• 2012

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters $K_m$, $V_{max}$, and $k_{cat}$ for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at $50^{\circ}C$, but the optimal temperature of activity was $37^{\circ}C$. It also showed maximal and optimal activities at pH 9.0. The values of $K_m$, $V_{max}$, $k_{cat}$, and $k_{cat}/K_m$ were $8.9{\pm}0.967{\times}10^{-3}$ M, $128{\pm}2.8$ U/mg protein, $106{\pm}2s^{-1}$, and $1.2{\pm}0.105{\times}10^4M^{-1}s^{-1}$, respectively. The L-asparaginase activity was reduced in the presence of $Mn^{2+}$, $Zn^{2+}$, $Ca^{2+}$, and $Mg^{2+}$ metal ions for about 52% to 31%. In addition, we found that $NH_4{^+}$, L-Asp, D-Asn, and ${\beta}$-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobial-type asparaginase II family.

• Molecules and Cells
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• 제27권4호
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• pp.423-428
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• 2009

Superoxide dismutases (SODs) constitute the first line of cellular defense against oxidative stress in plants. SODs generally occur in three different forms with Cu/Zn, Fe, or Mn as prosthetic metals. We cloned the full-length cDNA of the Thellungiella halophila Cu/Zn-SOD gene ThCSD using degenerate RT-PCR and rapid amplification of cDNA ends (RACE). Sequence analysis indicated that the ThCSD gene (GenBank accession number EF405867) had an open reading frame of 456 bp. The deduced 152-amino acid polypeptide had a predicted molecular weight of 15.1 kDa, an estimated pI of 5.4, and a putative Cu/Zn-binding site. Recombinant ThCSD protein was expressed in Escherichia coli and assayed for SOD enzymatic activity in a native polyacrylamide gel. The SOD activity of ThCSD was inactivated by potassium cyanide and hydrogen peroxide but not by sodium azide, confirming that ThCSD is a Cu/Zn-SOD. Northern blotting demonstrated that ThCSD is expressed in roots, stems, and leaves. ThCSD mRNA levels increased by about 30-fold when plants were treated with sodium chloride (NaCl), abscisic acid (ABA), and indole-acetic acid (IAA) and by about 50-fold when treated with UVB light. These results indicate that ThCSD is involved in physiological pathways activated by a variety of environmental conditions.

• BMB Reports
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• 제52권8호
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• pp.496-501
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• 2019

Conventionally, immunotoxins have been produced as a single polypeptide from fused genes of an antibody fragment and a toxin. In this study, we adopted a unique approach of chemical conjugation of a toxin protein and an antibody fragment. The two genes were separately expressed in Escherichia coli and purified to high levels of purity. The two purified proteins were conjugated using a chemical linker. The advantage of this approach is its ability to overcome the problem of low recombinant immunotoxin production observed in some immunotoxins. Another advantage is that various combinations of immunotoxins can be prepared with fewer efforts, because the chemical conjugation of components is relatively simpler than the processes involved in cloning, expression, and purification of multiple immunotoxins. As a proof of concept, the scFv of trastuzumab and the PE24 fragment of Pseudomonas exotoxin A were separately produced using E. coli and then chemically crosslinked. The new immunotoxin was tested on four breast cancer cell lines variably expressing HER2. The chemically crosslinked immunotoxin exhibited cytotoxicity in proportion to the expression level of HER2. In conclusion, the present study revealed an alternative method of generating an immunotoxin that could effectively reduce the viability of HER2-expressing breast cancer cells. These results suggest the effectiveness of this method of immunotoxin crosslinking as a suitable alternative for producing immunotoxins.

• 대한화장품학회지
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• 제47권1호
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• pp.65-73
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• 2021

피부 염증은 흉터, 노화 뿐만 아니라 아토피와 같은 질환으로 발전할 수 있어 이를 조절하는 것이 매우 중요하다. 본 연구에서는 최근 인체에서 염증을 조절하는 것으로 알려진 specialized pro-resolving mediators (SPMs)의 in vitro 합성과 화장품 적용 가능성을 확인하였다. 대두의 lipoxygenase를 이용하여 mono 또는 di-hydroxy docosahexaenoic acid가 혼합된 시료 S-SPMs를 제작하였고 효능 평가에 이용하였다. 먼저, UVB로 염증을 유도한 세포에서 TNF-α와 IL-6의 발현이 S-SPMs에 의해 감소하고, 미세먼지에 의해 유도된 nitric oxide (NO)의 생성 역시 감소하는 것을 확인하여 S-SPMs의 항염 효능을 확인하였다. 또한, S-SPMs을 처리한 조건에서 malondialdehyde (MDA) 생성이 감소하여 지질 과산화 억제능이 있음을 확인하였고 S-SPMs에 의한 matrix metalloproteinase-1 (MMP-1)의 발현 감소, procollagen type I의 함량 증가를 통해 collagen 분해를 억제하고 반대로 합성은 촉진함을 확인하였다. 끝으로 filaggrin과 loricrin의 발현이 S-SPMs에 의해 증가한 것을 확인하여 피부 장벽 강화 효능을 확인하였다. 위 결과를 토대로 S-SPMs은 피부의 염증 억제와 함께 손상회복, 주름개선 및 장벽 강화를 위한 소재로 활용 가능함을 확인하였다.

• 한국미생물·생명공학회지
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• 제36권3호
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• pp.182-188
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• 2008

내열성 Trehalose synthase를 생산하는 초고온성 균주 HJ6은 일본 Arima 온천수에서 분리하였다. 세포의 길이는 $2{\sim}4\;um$, 직경 0.4 um의 간균으로 생육최적 pH와 온도는 각각 6.5와 $80^{\circ}C$이였다. 분리된 균주의 16s rRNA 염기서열을 분석하고 계통학적으로 분류한 결과, HJ6 균주는 Thermus thermophilus에 속하는 것으로 동정되었다. PCR법을 이용하여 trehalose synthase(TS) 유전자를 클로닝하고 염기서열을 분석한 결과, ORF는 2,898개의 뉴클레오타이드로 구성되고 915개의 아미노산을 암호화하였다. 아마노산 서열을 바탕으로 상동성을 분석한 결과, Thermus caldophilus GK24 유래 TS와 99%, Meiothermus ruber 유래 TS와 83%의 identity를 나타내었다. 이 유전자를 온도감수성 프로모터를 포함하는 pJLA503 벡터를 이용하며 대장군에서 발현하고 정제하여 약 110 kDa 단백질을 얻을 수 있었다. 정제된 효소는 트레할로스 전환활성에 대한 최적 pH가 7.5이고, 최적온도는 $80^{\circ}C$이며, 활성의 반감기는 $90^{\circ}C$에서 40분으로 확인되어 높은 내열성을 가지는 것으로 확인되었다. 본 효소의 트레할로스 최대 전환율은 기질농도 500mM에서 55.7%를 나타내었고, 기질 농도가 증가함에 따라 더불어 증가하였기 때문에 본 효소의 트레할로스 전환율을 기질농도에 의존적인 것으로 생각되었다.

• 대한세포병리학회지
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• 제7권2호
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• pp.163-168
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• 1996

Abnormalities of p53 gene are common in lung cancers and are associated with immunologically detectable p53 protein. p53 immunoreactivity is uncommon in normal cells but is frequently seen in neoplasia. Therefore, assessment of p53 expression may assist in the cytological diagnosis of malignancy. The usefulness of p53 immunostaining as a marker of malignancy in the cytological analysis of bronchial brush specimens from the patients with lung cancers was investigated in this study. A total of 71 bronchial brush samples submitted for cytologic diagnosis were immunostained with D07, a monoclonal antibody to recombinant p53 protein. Resultant p53 data were correlated with cytologic diagnosis and clinical information. Of the 17 smears with a benign cytodiagnosis, all were p53 negative. Of the 40 cases with a malignant cytodiagnosis (histologically confirmed), 35 were p53 positive and 5 were negative. Of the 14 cases that were cytologically suspicious but nondiagnostic for malignancy, 11 were p53 positive, 9 of which were subsequently proved to be malignant by histologic examination, and the remaining 2 cases were tuberculosis clinically. Forty four of 51 histologically confirmed lung carcinomas were p53 positive, including 25 of 28 squamous cell carcinomas, 13 of 17 small cell carcinomas, 3 of 3 adenocarcinomas, and 3 of 3 large cell undifferentiated carcinomas. These results suggest that p53 immunostaining could be of value as a marker of malignancy in the cytologic examination of bronchial brush specimens. Furthermore, we have shown the possible clinical utility of p53 immunostaining in cytopathological diagnosis, that is, as a valuable adjunct to morphological assessment in the analysis of cytopathologically suspicious cases.

• 한국미생물·생명공학회지
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• 제36권4호
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• pp.299-306
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• 2008

사람 췌장 리파아제는 췌장에서 합성되어 소장으로 분비된 후, 음식물속의 지방을 가수분해하는 소화효소이다. 췌장 리파아제 단백질은 촉매활성도메인과 코리파아제 결합도메인의 2개의 도메인으로 구성되어 있다 본 연구에서는 리파아제 전체단백질과 촉매활성도메인 및 코리파아제 결함도메인 유전자를 PCR 방법으로 증폭하여 발현벡터에 넣은 후, 대장균에서 발현시켜 얻은 3가지 재조합 단백질을 산란계에 3차례 주사하여 면역반응을 유도하였다. 난황단백질을 분리하여 항체가를 측정한 결과, 코리파아제 결합도메인의 항원성이 가장 높은 것으로 밝혀졌다. 또한, 돼지 췌장 리파아제의 활성저해 실험에서도 코리파아제 결합도메인에 의해 만들어진 난황항체가 지방분해활성 저해작용이 가장 큰 것으로 밝혀졌다. 코리파아제 결합도메인 난황항체가 첨가된 지방을 실험동물에게 급여하고 혈중 주요 성분을 분석한 결과, 코리파아제 결합도메인에 의한 난황항체를 섭취한 경우에 혈중 중성지방의 수치가 대조군에 비해서 유의적으로 감소했음을 화인하였다. 결론적으로 코리파아제 결합도메인을 항원단백질로 사용하여 얻은 난황항체가 생체 내에서 췌장 리파아제의 활성을 억제할 수 있으며 비만억제제로의 개발 가능성이 있음을 보여주었다.

• BMB Reports
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• 제39권6호
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• pp.696-702
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• 2006

Recently three proteins, playing central roles in the bidirectional transport of urate in renal proximal tubules, were identified: two members of the organic anion transporter (OAT) family, OAT1 and OAT3, and a protein that designated renal urate-anion exchanger (URAT1). Antibodies against these transporters are very important for investigating their expressions and functions. With the cytokine gene as a molecular adjuvant, genetic immunization-based antibody production offers several advantages including high specificity and high recognition to the native protein compared with current methods. We fused high antigenicity fragments of the three transporters to the plasmids pBQAP-TT containing T-cell epitopes and flanking regions from tetanus toxin, respectively. Gene gun immunization with these recombinant plasmids and two other adjuvant plasmids, which express granulocyte/macrophage colony-stimulating factor and FMS-like tyrosine kinase 3 ligand, induced high level immunoglobulin G antibodies, respectively. The native corresponding proteins of URAT1, OAT1 and OAT3, in human kidney can be recognized by their specific antibodies, respectively, with Western blot analysis and immunohistochemistry. Besides, URAT1 expression in Xenopus oocytes can also be recognized by its corresponding antibody with immuno-fluorescence. The successful production of the antibodies has provided an important tool for the study of UA transporters.