• 한국미생물·생명공학회지
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• 제47권2호
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• pp.242-249
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• 2019

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA, the aspC, ipdC, and iad1 from Escherichia coli, Enterobacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iad1 were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/min/mg-protein, respectively. The final resulting strain expressing aspC, ipdC, and iad1 produced 2.3 g/l and 7.3 g/l of IAA from 10 g/l L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.56-59
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• 2000

Thermophilic bacterium, Bacillus stearothermophilus NUB3621, was engineered to produce ethanol from glucose by introducing cloned thermostable pyruvate decarboxylase and alcohol dehydrogenase genes. A novel promoter sequence was screened and used for the enhancement of these two enzymes. Successful redirection of metabolic flux into ethanol was obtained. In addition, gene expression profiling using Bacillus subtilis DNA microarray was analyzed to overcome the intrinsic low glucose utilization of B.stearothermophilus. Many known and unknown genes were identified to be up or down regulated under glucose-containing media.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.251-259
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• 2013

An endoxylanase gene (PoxynA) that belongs to the glycoside hydrolase (GH) family 11 was cloned from a xylanolytic strain, Penicillium oxalicum B3-11(2). PoxynA was overexpressed in Trichoderma reesei QM9414 by using a constitutive strong promoter of the encoding pyruvate decarboxylase (pdc). The high extracellular xylanase activities in the fermentation liquid of the transformants were maintained 29~35-fold higher compared with the wild strain. The recombinant POXYNA was purified to homogeneity, and its characters were analyzed. Its optimal temperature and pH value were $50^{\circ}C$ and 5.0, respectively. The enzyme was stable at a pH range of 2.0 to 7.0. Using beechwood as the substrate, POXYNA had a high specific activity of $1,856{\pm}53.5$ IU/mg. In the presence of metal ions, such as $Cu^{2+}$, and $Mg^{2+}$, the activity of the enzyme increased. However, strong inhibition of the enzyme activity was observed in the presence of $Mn^{2+}$ and $Fe^{2+}$. The recombinant POXYNA hydrolyzed birchwood xylan, beechwood xylan, and oat spelt xylan to produce short-chain xylooligosaccharides, xylopentaose, xylotriose, and xylobiose as the main products. This is the first report on the expression properties of a recombinant endoxylanase gene from Penicillium oxalicum. The properties of this endoxylanase make it promising for applications in the food and feed industries.

• Journal of Plant Biotechnology
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• 제4권1호
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• pp.7-15
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• 2002

Eight cDNAs corresponding to fruit-specific genes were isolated from ripened melon through differential screening. Sequence comparison indicated that six of these cDNAs encoded proteins were previously characterized into aminocyclopropane-1-carboxylate (ACC) oxidase, abscisic acid, stress and ripening inducible (ASR) gene, RINC-H2 zinc finger protein, pyruvate decarboxylase, or polyubiquitin. RFS2 and RFS5 were the same clone encoding polyubiquitin. The other cDNAs showed no significant homology with known protein sequences. The ASR homologue (Asr1) gene was further characterized on the cDNA and genomic structure. The deduced amino acid sequence had similar characteristics to other plant ASR. The Asr1 genomic DNA consisted of 2 exons and 1 intron, which is similar to the structure of other plants ASR genes. The promoter region of the Asr1 gene contained several putative functional cis-elements such as an abscisic acid responsive element (ABRE), an ethylene responsive element (ERE), a C-box or DPBf-1 and 2, Myb binding sites, a low temperature responsive element (LTRE) and a metal responsive element (MRE). The findings imply that these elements may play important roles in the response to plant hormones and environmental stresses in the process of fruit development. The results of this study suggest that the expressions of fruit specific and ripening-related cDNAs are closely associated with the stress response.

• 한국미생물·생명공학회지
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• 제35권4호
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• pp.272-277
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• 2007

P. pastoris는 대장균에 비해 정확한 접힘, 당화, 효율적인 분비기작등의 장점을 가지고 있어 재조합 단백질의 생산을 위한 균주로서 관심을 받고 있다. 또한 재조합 단백질의 효율적인 생산공정 개발을 위하여 배양공정 중 특정 시간이나 조건에서 발현될 수 있는 효율적인 유도성 프로모터의 개발도 중요 관심 분야이다. 본 연구에서는 연속배양을 이용하여 P. pastoris의 배양 중 특정 기질이 소모되었을 때 발현되는 자동 유도성 프로모터를 개발하기 위하여, 인산이 고갈되었을 때 과발현 되는 유전자들을 탐색하였다. 인산 제한 연속배양의 정상상태에서 얻어진 균체로 부터 total RNA와 mRNA를 분리하였고, 이로부터 cDN를 합성하여 인산제한조건에서 과발현되는 유전자들을 확보하였다. 그 중 빈도수가 높은 8종의 유전자 3-phosphoglycerate kinase, glyceraldehyde 3-phosphate dehydrogenase(GAPDH), glucokinase, thiol-specific antioxidant protein, triosephosphate isomerase, sodium/phosphate symporter(NPS) 그리고 pyruvate decarboxylase를 선별하였고, Northern blot analysis를 수행한 결과 인산 섭취에 관련된 NPS 유전자가 인산제한조건에서 과발현 됨을 확인하였다. 본 연구실에서는 자동유도성 프로모터로서 NPS유래의 프로모터의 잠재성을 알아보기 위하여, 관련 유전자를 확보하여 외래 유전자를 이용한 발현연구를 진행 중이다.