• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.322-328
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• 2013

In this study, we show the expression and purification of the human recombinant farnesoid X receptor (FXR)- ligand binding domain (LBD) protein in E. coli using a double cistronic vector, pACYCDuet-1, as a soluble form. We describe here the expression and characterization of a biologically active $FXR-LBD_{(248-476)}$. When expressed in the influence of bacterial promoters ($P_{T7}$ and $P_{Tac}$) of the single cistronic expression vectors, the human recombinant $FXR-LBD_{(248-476)}$ was found to be totally insoluble. However, by using a double cistronic expression vector, we were able to obtain the human recombinant $FXR-LBD_{(248-476)}$ in a soluble form. To allow for biological activities, we have subcloned into the pACYCDuet-1 vector, expressed in E. coli cells at some optimized conditions, and purified and characterized the human recombinant active $FXR-LBD_{(248-476)}$ proteins using the fluorescence polarization assay. This suggests that the expression of FXR-LBD in a double cistronic vector improves its solubility and probably assists its correct folding for the biologically active form of the proteins. We suggest that this may represent a new approach to high expression of other nuclear receptors and may be useful as well for other classes of heterodimeric protein partners.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1362-1368
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• 2006

A new constitutive episomal expression vector, pGAPZ-E, was constructed and used for initial screening of eukaryotic target gene expression in Pichia pastoris. Two reporter genes such as beta-galactosidase gene and GFPuv gene were overexpressed in P. pastoris. The expression level of the episomal pGAPZ-E strain was higher than that of the integrated form when the beta-galactosidase gene was used as the reporter gene in P. pastoris X33. The avoiding of both the integration procedure and an induction step simplified the overall screening process for eukaryotic target gene expression in P. pastoris. Nine human protein targets from the Core 50, family of Northeast Structural Genomics Consortium (http://www.nesg.org), which were intractable when expressed in E. coli, were subjected to rapid screening for soluble expression in P. pastoris. HR547, HR919, and HR1697 human proteins, which had previously been found to express poorly or to be insoluble in E. coli, expressed in soluble form in P. pastoris. Therefore, the new episomal GAP promoter vector provides a convenient and alternative system for high-throughput screening of eukaryotic protein expression in P. pastoris.

• 자연과학논문집
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• 제4권
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• pp.1-10
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• 1991

발현 Vector인 pKK223-3를 이용하여 효모 Thiol-Specific Antioxidant단백질 유전자를 대장균에 도입시켜 이 단백질을 발현시켰다. 이 단백질은 대장균 단백질의 약 1% 정도로 발현되었으며, 물리 및 화학적 특성은 효모의 것과 동일한 특성을 보였다.

• Journal of Microbiology
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• 제43권4호
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• pp.354-360
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• 2005

Heat-labile enterotoxin B subunit (LTB) of enterotoxigenic Escherichia coli (ETEC) is both a strong mucosal adjuvant and immunogen. It is a subunit vaccine candidate to be used against ETEC-induced diarrhea. It has already been expressed in several bacterial and plant systems. In order to construct yeast expressing vector for the LTB protein, the eltB gene encoding LTB was amplified from a human origin enterotoxigenic E. coli DNA by PCR. The expression plasmid pLTB83 was constructed by inserting the eltB gene into the pYES2 shuttle vector immediately downstream of the GAL1 promoter. The recombinant vector was transformed into S. cerevisiae and was then induced by galactose. The LTB protein was detected in the total soluble protein of the yeast by SDS-PAGE analysis. Quantitative ELISA showed that the maximum amount of LTB protein expressed in the yeast was approximately $1.9\%$ of the total soluble protein. Immunoblotting analysis showed the yeast-derived LTB protein was antigenically indistinguishable from bacterial LTB protein. Since the whole-recombinant yeast has been introduced as a new vaccine formulation the expression of LTB in S. cerevisiae can offer an inexpensive yet effective strategy to protect against ETEC, especially in developing countries where it is needed most.

• 생명과학회지
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• 제25권2호
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• pp.130-135
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• 2015

Pseudoalteromonas elyakovii 유래 alginate lyase 유전자(aly)를 대장균에서 발현시켰을 때, 발현된 대부분의 유전자 산물은 내포체라는 불용성 응집체 형태로 생산되었다. Alginate lyase를 가용성 및 활성형으로 생산하기 위해 Aeropyrum pernix K1 유래의 초고온성 샤페로닌 ApCpnA와 ApCpnB를 공발현 파트너로 도입하였다. aly와 ApCpnA와 ApCpnB 각각과의 공발현 결과, aly 단독발현 때의 alginate lyase 활성 10.1 unit/g-soluble protein에서 ApCpnA와의 공발현 때는 83.1 unit/g-soluble protein, ApCpnB와의 공발현 때는 100.3 unit/g-soluble protein으로 가용성 및 활성형으로의 alginate lyase 생산이 8~10배 크게 향상되었다. 다양한 배양 조건들의 조사를 통해 alginate lyase 최대 생산을 위한 조건은 다음과 같았다: 1.0 mM IPTG, $25^{\circ}C$ 배양 온도(IPTG 유도 후), ApCpnB 공발현 파트너. 이러한 공발현 시스템은 대장균에서 기능적으로 또한 의학적으로 중요한 재조합 단백질의 산업적 생산에 크게 유용하게 사용될 것이다.

• 약학회지
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• 제51권5호
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• pp.291-295
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• 2007

The present study examines the effect of dominant-negative Akt on the insulin-mediated microsomal epoxide hydrolase (mEH) induction in rat hepatocytes. We also assessed the role of insulin in the expression of soluble epoxide hydrrolase (sEH). Insulin increased mEH levels and the enzyme activities, whereas sEH protein expression was unaffected by insulin. The specific PI3K inhibitors or p70 S6 kinase inhibitor ameliorated the insulin-mediated increase in mEH protein levels. Infection with adenovirus expressing dominant-negative and kinase-dead mutant of Akt1 effectively inhibited the insulin-mediated increase in mEH expression and mEH activity. These results suggest that mEH and sEH are differentially regulated by insulin and PI3K/Akt/p70S6K are active in the insulin-mediated regulation of mEH expression.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.274-279
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• 2015

Receptor activator of nuclear factor-kappa B ligand (RANKL) is a critical factor in osteoclastogenesis. It makes osteoclasts differentiate and multinucleate in bone remodeling. In the present study, RANKL was expressed as a soluble maltose binding protein (MBP)-fusion protein using the Escherichia coli maltose binding domain tag system (pMAL) expression vector system. The host cell E. coli DH5α was cultured and induced by isopropyl β-_D-1-thiogalactopyranoside for rRANKL expression. Cells were disrupted by sonication to collect soluble MBP-fused rRANKL. The MBP-fusion rRANKL was purified with MBP Trap affinity chromatography and treated with Tobacco Etch Virus nuclear inclusion endopeptidase (TEV protease) to remove the MBP fusion protein. Dialysis was then carried out to remove binding maltose from the cleaved rRANKL solution. The cleaved rRANKL was purified with a second MBP Trap affinity chromatography to separate unsevered MBP-fusion rRANKL and cleaved MBP fusion protein. The purified rRANKL was shown to have biological activity by performing in vitro cell tests. In conclusion, biologically active rRANKL was successfully purified by a simple two-step chromatography purification process with one column.

• 미생물학회지
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• 제37권4호
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• pp.245-252
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• 2001

MLS (macrolide-lincosamide-streptogramin B) 항생제 내성인자 단백질인 Erm 단백질들은 아미노산 서열 중 그 동일성과 유사성이 높아 구조적으로도 동등한 단백질의 한 집단을 형성한다. 최근 X-ray crystallography에 의해 구조가 결정된 ErmC\` 및 ErmAM 단백질의 구조에 근거하여 ErmSF 단백질도 catalytic domain과 substrate binding domain으로 구분하였고 N-terminal end에 존재하는 catalytic domain의 대량생산을 다양한 pET 발현 vector를 사용하여 시도하였다. 그리고 catalytic domain을 coding하는 DNA 절편은 세 종류를 사용하였다: DNA 절편 1은 Met 1부터 Glu 186까지를 coding하고 DNA 절편 2는 Arg 60부터 Glu 186까지의 정보를 가진 DNA이고 DNA 절편 3은 Arg 60부터 Arg 240까지를 encoding하는 DNA이다. 사용된 다양한 발현 vector중에서 pET19b는 DNA 절편 3, pET23b는 DNA 절편 1과 2를 성공적으로 대량생산하였다. 그러나 대량생산된 catalytic domain들은 불용성 단백질 집합체인 inclusion body를 형성하였다. ErmSF catalytic domain들의 용해성 단백질의 생산을 위하여 chaperone GroESL과 Thioredoxin의 동시 발현 및 배양온도를 $22^{\circ}C$로 낮추어 시도했으나 대량 발현된 단백질의 용해에는 도움을 얻지 못하였다.

• Toxicological Research
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• 제14권3호
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• pp.371-377
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• 1998

We have cloned a soluble type human folate receptor(hFR type${\gamma}$) from human thymus cDNA library using the PCR amplification technique. To examine whether hFR type${\gamma}$ has a folate transport activity, CHO cells were transfected with the pcDNAhFR${\gamma}$ expression plasmid, and the stable cell line CHO/hFR${\gamma}$ expressing a high level of the hFR type${\gamma}$ was identified by northern and western blot analysis. The CHO/hFR${\gamma}$ cells produced a [$H^3$]folic acid binding protein in the culture medium. However, we couldn't detect any cell surface [$H^3$] folic acid binding and transport activities. The growth of the CHO/hFR${\gamma}$ cells was more rapidly inhibited than the wild type CHO cells in the low concentration folic acid media. These observations indicate that although soluble type human folate receptor can bind [$H^3$]folate, it does not involve in folate transport.

• Molecules and Cells
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• 제26권2호
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• pp.140-145
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• 2008

Expression of olive flounder hepcidin I (HepI) fused with truncated OmpA signal peptides ($OmpASP_{tr}$) as directional signals does not produce soluble fusion proteins. However, by inserting amino acid segments (xxx) varying in pI and hydrophobicity/hydrophilicity into a leader sequence containing a truncated OmpASP ($OmpASP_{tr}$) and a factor Xa cleavage site (Xa) [$OmpASP_{tr}{\mid}(xxx){\mid}Xa$], we were able in some cases to express soluble recombinant HepI. Soluble expression of the recombinant protein strongly correlated with (xxx) insertions of high pI and hydrophilicity. Therefore, we modified the $OmpASP_{tr}{\mid}(xxx){\mid}Xa$ sequence by inserting Arg and Lys into (xxx) to increase the hydrophilicity of the signal peptide region. These modifications enhanced the expression of soluble recombinant HepI. Hydropathic profile analysis of the $OmpASP_{tr}{\mid}(xxx){\mid}Xa$ HepI fusion proteins revealed that the transmembrane-like domains derived from the $OmpASP_{tr}{\mid}(xxx){\mid}Xa$ sequence were larger than the internal positively charged domain native to HepI. It should therefore be possible to overcome the obstacle of internal positively charged domains to obtain soluble expression of recombinant proteins by monitoring the hydrophilicity and hydropathic profile of the signal peptide region using a computer program.