• 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.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.966-971
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• 2009

Peroxidase from Coprinus cinereus (CiP) has attracted attention for its high specific activity and broad substrate spectrum compared with other peroxidases. In this study, the functional expression of this peroxidase was successfully achieved in the methylotrophic yeast Pichia pastoris. The expression level of CiP was increased by varying the microbial hosts and the expression promoters. Since a signal sequence, such as the alpha mating factor of Saccharomyces cerevisiae, was placed preceding the cDNA of the CiP coding gene, expressed recombinant CiP (rCiP) was secreted into the culture broth. The Mut Pichia pastoris host showed a 3-fold higher peroxidase activity, as well as 2-fold higher growth rate, compared with the $Mut^s $ Pichia pastoris host. Furthermore, the AOX1 promoter facilitated a 5-fold higher expression of rCiP than did the GAP promoter.

• KSBB Journal
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• 제24권4호
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• pp.341-346
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• 2009

본 연구에서는 Candida antarctica로부터 genomic DNA을 추출하여 lipase A(CalA) 유전자를 PCR 증폭하였고, 재조합 pColdIII/CalA, $pPICZ{\alpha}A$/CalA, $pPICZ{\alpha}A$/CalA$his{\times}6$을 구축하였다. 재조합 CalA 유전자의 기능적 발현을 위해 최적화된 시스템을 구축하고자 Escherichia coli와 Pichia pastoris 시스템에서 각각 수행하여 비교, 분석하였다. SDS PAGE gel을 통해 CalA의 발현의 여부 및 발현양을 확인하였고, pNPP를 기질로 한 가수분해 반응을 통해 활성을 측정하였다. E. coli 발현 시스템은 형질전환 방법이 간단하고, 미생물의 성장 속도가 빠르다는 장점을 갖지만 CalA의 활성이 0.02 Unit/ml으로 비교적 낮았으며 세포질 (cytoplasm)에서 발현되므로 비목적 단백질과의 분리 및 정제과정이 필요하다. 재조합 $pPICZ{\alpha}A$/CalA을 P. pastoris 시스템에서 발현한 경우 높은 발현양 뿐만 아니라 분비작용으로 인해 고순도 발현이 용이하였고, 활성 또한 약 0.7 Unit/ml으로 가장 높았다. 결론적으로 CalA의 기능적 발현을 위해 P. pastoris 시스템을 구축하는 것이 가장 적합함을 확인하였다.

• 한국미생물·생명공학회지
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• 제35권3호
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• pp.184-190
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• 2007

대략 2 kb의 크기를 가진 Pichia pastoris phosphoglycerate kinase gene (PGK1)의 프로모터부분을 266bp의 작은 크기로 최소화하여 P. pastoris에 있어 episomal의 새로운 항시적 발현벡터를 제조하였다. P. pastoris의 새로운 항시적 발현벡터를 개발하기 위하여 기존의 Pichia발현벡터인 pGABZB의 GAP프로모터부분을 연속적으로 일정 부분이 절단된 PGK1프로모터에 beta-galactosidase유전자가 결합된 부분으로 치환하였다. LacZ유전자를 reporter유전자로 사용하였을 때에 PGK1프로모터의 발현세기는 다른 항시적 프로모터인 GAP프로모터 보다는 낮았지만 TEF1프로모터 보다는 높았다. 본 논문에서 PGK1 프로모터의 불필요한 부분을 제거함으로서 Pichia에서 외래발현을 위한 새로운 episomal발현벡터인 pPGKZ-E를 제조하였으며 이 것은 P. pastoris에 있어 발현세기를 선택할 수 있는 발현벡터선택의 폭을 넓게 하였다.

• Journal of Microbiology and Biotechnology
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• 제19권2호
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• pp.172-177
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• 2009

A gene(lsd1) encoding dextranase from Lipomyces starkeyi KSM22 has been previously cloned, sequenced, and expressed in Saccharomyces cerevisiae. The gene consisting of 1,824 base pairs and encoding a protein of 608 amino acids was then cloned into and secretively expressed in Pichia pastoris under the control of the AOX1 promoter. The dextranase productivity of the P. pastoris transformant(pPIC9K-LSD1, 134,000 U/I) was approximately 4.2-fold higher than that of the S. cerevisiae transformant(pYLSD1, 32,000 U/I) cultured in an 8-1 fermentor. Over 0.63 g/l of active dextranase was secreted into the medium after methanol induction. The dextranase of the P. pastoris transformant, as analyzed by SDS-PAGE and Western blotting, showed only one homogeneous band. This dextranase of the P. pastoris transformant showed a broad band near 73 kDa. Rabbit monoclonal antibodies against a synthetic LSD1 peptide mix also recognized approximately 73 kDa.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.348-355
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• 2012

본 연구에서는 S. cerevisiae와 P. pastoris에서 bovine pancreatic (bp-) DNase I의 과발현과 재조합 DNase I의 특성을 조사하였다. bp-DNase I 유전자는 GAL10 promoter, $MF{\alpha}$, GAL7 terminator 사이에 삽입하여 재조합 plasmid인 pGAL-$MF{\alpha}$-DNaseI (6.4 kb)를 구축하였다. 그리고 bp-DNase I 유전자를 AOX1 promoter, $MF{\alpha}$, AOX1 terminator 에 삽입하여 재조합 plasmid인 pPEXI (8.8 kb)를 구축하였다. 재조합 plasmid인 pGAL-$MF{\alpha}$-DNaseI과 pPEXI를 각각 S. cerevisiae와 P. pastoris 숙주세포에 형질전환시켰다. 형질전환된 효모세포들을 galactose와 methanol 배지에서 $30^{\circ}C$, 48시간 배양하면 bp-DNase I은 대부분이 배양 상등액으로 과발현되었다. P. pastoris 형질전환체는 배양 상등액에서 45.5 unit/mL의 DNase I 활성을 보였으며, 반면에 S. cerevisiae 형질전환체는 37.7 unit/mL의 DNase I 활성을 보였다. 또한 DNA 분해 특성을 조사한 결과, P. pastoris 재조합 DNase I으로 기질 DNA(calf thymus)를 처리하였을 때 1분 이내 DNA가 분해되는 것을 확인할 수 있었으며 이는 상업용 bp-DNase I과 S. cerevisiae 재조합 DNase I으로 처리했을 때보다 빠른 분해 패턴을 보였다.

• 동아시아식생활학회지
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• 제16권5호
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• pp.559-563
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• 2006

This research was performed to investigate the potential use of Capsella bursa-pastoris (L.) as an ingredient to improve the biological function and flavor of kimchi. The quality characteristics were studied for kimchi with or without Capsella bursa-pastoris (L.) Medicus (CBM kimchi) during fermentation for 25 days at $10^{\circ}C$. The pH changes of CBM kimchi were slower than those of control but did not show any significant difference after addition of Capsella bursa-pastoris (L.) Medicus during fermentation. The titratable acidity of CBM kimchi was higher than that of control. The log number of total bacteria was lower about 1.5 $log_{10}$ cycle in CBM kimchi than in control during fermentation. However, lactic acid bacteria did not show significant difference between CMB kimchi and control. Sensory qualities of kimchi such as color, taste, flavor and overall acceptability were significantly improved by addition of 3% Capsella bursa-pastoris (L.) Medicus(p<0.05).

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1185-1191
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• 2006

The expression of a pullulanase gene in Pichia pastoris was investigated. The gene encoding pullulanase was cloned by PCR using the chromosomal DNA of Bacillus naganoensis as the template. The expression vector pPIC9K-Pu was constructed by inserting the pullulanase gene into plasmid pPIC9K and then transformed into Pichia pastoris SMD 1168 by electroporation. Activity determination, SDS-PAGE, and PCR amplification indicated that the gene of the pullulanase from B. naganoensis had successfully been expressed in SMD 1168 and the molecular size of the expressed recombinant product was about 119.9 kDa. This is the first report on the successful expression of the pullulanase from B. naganoensis in P. pastoris. The transformant secreted recombinant pullulanase with the activity of 350.8 IU/ml in shake-flask culture. The properties of the recombinant pullulanase were characterized.

• KSBB Journal
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• 제14권4호
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• pp.482-489
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• 1999

As host for the production of eucaryotic heterologous proteins, methylotrophic yeast Pichia pastoris and Hansenula polymorpha are the most highly developed of a small group of alternative yeast species chosen for their perceived advantages. This paper describes the method to enhance the recombinant protein productivity with P. pastoris and H. Plymorpha. In these experiments, the effects of methanol induction timing, induction method, pH, culture temperature and kinds of nitrogen sources on foreign protein production were tested with P. pastoris and compared with H. polymorpha.. In addition, optimum methanol concentration as inducer and the effects of carbon sources on AOX1 or MOX promoter repression and secretion efficiency were also studied in both cases.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.152-159
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• 2014

The regulation of protein tyrosine phosphorylation is mediated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) and is essential for cellular homeostasis. Co-expression of PTKs with PTPs in Pichia pastoris was used to facilitate the expression of active PTKs by neutralizing their apparent toxicity to cells. In this study, the gene encoding phosphatase PTP1B with or without a blue fluorescent protein or peroxisomal targeting signal 1 was cloned into the expression vector pAG32 to produce four vectors. These vectors were subsequently transformed into P. pastoris GS115. The tyrosine kinases EGFR-2 and $PDGFR{\beta}$ were expressed from vector pPIC3.5K and were fused with a His-tag and green fluorescent protein at the N-terminus. The two plasmids were transformed into P. pastoris with or without PTP1B, resulting in 10 strains. The EGFR-2 and $PDGFR{\beta}$ fusion proteins were purified by $Ni^{2+}$ affinity chromatography. In the recombinant P. pastoris, the PTKs co-expressed with PTP1B exhibited higher kinase catalytic activity than did those expressing the PTKs alone. The highest activities were achieved by targeting the PTKs and PTP1B into peroxisomes. Therefore, the EGFR-2 and $PDGFR{\beta}$ fusion proteins expressed in P. pastoris may be attractive drug screening targets for anticancer therapeutics.