• Korean Journal of Microbiology
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• v.40 no.4
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• pp.359-363
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• 2004

I investigated an effective way to generate a metagenomic library from DNA prepared from environental samples. The sizes of DNA extracted from environmental samples were usually in the range of 10 to 100 kbp as estimated from $0.4\%$ agarose gel electrophoresis. Because of this small size, a fosmid, rather than BAC, was chosen as a vector. It was found that, for the successful generation of metagenomic library, the selection of DNA with the sized of about 40 kbp was critical and, therefore, a simple agarose gel electrophoresis system was developed to select this size of DNA. By the procedure described in this report, I obtained metagenomic libraries containing 25,000 fosmid clones, which corresponded to 1,000 Mb of metagenomic DNA.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.3
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• pp.543-552
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• 2014

Papain family중 하나인 cysteine protease는 근골격계 질환 치료를 위한target molecule로 인식 되어왔으며 Cathepsin B 는 단백질 분해의 초기과정에 관여하는 cysteine proteases 중 하나이다. 본 연구는 넙치의 cathepsin B 유전자의 발현 양상과 넙치 cathepsin B(PoCtB)의 클로닝, 발현 및 효소특성을 분석하였다. cDNA Library Screening을 이용하여 넙치의 cDNA를 클로닝하였다. 넙치의 동정된 cathepsin B 유전자는 993bp의 open reading frame과 330개의 아미노산으로 이루어져있다. Cathepsin B의 propeptide region 내에 GNFD motif와 occluding loop 가 존재함으로써 이것이 명백하게 cathepsin B group이라는 것을 보여주며, 계통 유전학적 분석 결과 다른 종의 cathepsin B에 비해 초창기에 분화되어 나온 것으로 사료된다. mature enzyme인 maPoCtB은 fusion protein인 glutathione S-transferase를 포함하는 pGEX-4T-1 vector에 삽입하여 E.coli 균주인 $DH5{\alpha}$ 내에 발현시켰다. 재조합 단백질인 PoCtB을 과발현 시킨 결과 53kDa의 분자량을 가진다. 넙치 cathepsin B 활성은 Z-Arg-Arg-AMC와 같은 fluorogenic 펩타이드 기질을 이용하여 측정되었고 적정 pH는 pH.7.5 이다.

• Korean Journal of Microbiology
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• v.36 no.3
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• pp.192-195
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• 2000

Degenerate primevs corresponding to the consensus sequences of the copper-binding regions in the N- and Cterminal domains of fungal laccases were used to isolate laccase gene-specific sequences froin a white rot rungus Ganodern~a lucidrm w-hich has been known to strengthen the imnnne system. A 1.6 Kbp fragment was amplified by PCR and its base sequence was detenuiued. Locating seven iutrous within the base sequence, we could deduce its amino acid sequence. The nucleotide sequence witl~out introlls was 47Y0 identical to that of lee1 gene of Pametes wllosa; lhe identity in amino acid sequences of the two was 7994 The deduced amino acid seqoence was also sunilar to those of Coriolus versicolo~ kc3 (79%); Co~,iolz~s hirsutus phenolouiduse (78%), Trainetes vel.srcoloi. lccl (77%), Trametes ~!i/Iosa Ice2 (77%) and Trametes vemicolor kc4 (66%).

• Journal of Life Science
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• v.22 no.3
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• pp.306-311
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• 2012

A gene encoding a lipase, lipT, was cloned from the psychrotrophic bacterium Pseudomonas mandelii and sequenced. An open reading frame of 1,686 bp was found that encodes a polypeptide consisting of 562 amino acid residues. Sequence analysis revealed a Gly-His-Ser-Leu-Gly sequence, which matches the consensus Gly-X-Ser-X-Gly motif conserved among lipolytic enzymes. The recombinant LipT protein was predominantly expressed as inclusion bodies in Escherichia coli and subsequently purified by nickel-chelate affinity chromatography. A small fraction of LipT was refolded, and the subsequent LipT exhibited substrate preferences for p-nitrophenyl butyrate (C4) and p-nitrophenyl octanoate (C8).

• The Microorganisms and Industry
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• v.14 no.1
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• pp.22-28
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• 1988

DNA 클로닝과 조작기술의 발전은 어떤 유전자의 특정한 위치에 선택적으로 돌연변이를 도입할 수 있는 site-specific mutagenesis 기술을 창출해 내었다. 이 기술로 DAN 염기의 치환, 결실, 삽입등을 클론된 유전자에 직접 도입할 수가 있게 되어 생체의 유전자 조작이나 유전자의 산물인 단백질의 구조와 기능을 의도적으로 변화시키는 protein engineering에 광범위하게 이용되고 있다. Protein engineering은 주로 단백질의 촉매 및 생리활성의 증가, 효소의 특성및 기질 특이성의 변화, 단백질 구조의 안정화 및 내염성 증가, 분자량의 감소, 효소및 생리활성 단백질의 구조의 안정화및 내열성 증가 등에 활용되고 있으며 산업적 유용성이 큰새로운 단백질의 창조에도 기여할 것으로 기대를 모으고 있다. Site-specific mutagenesis 기술로 현재 가장 널리 이용되는 것이 in vitro상에서 수행하는 oligonucleotide-directed site specific mutagenesis이다. 이 방법은 생화학적으로 합성한 특정한 염기서열을 가진 oligonucleotide들을 일종의 mutagen으로 사용하거나 효소적 DNA 합성을 위한 primer로 사용하여 클론된 DNA의 염기서열을 선택적으로 개조하거나 혹은 다른 조작을 하는 것이다. 여기서는 돌연변이율을 높이는 여러가지 개량된 방법들이 나왔으며 그중의 몇가지를 소개하였다.

• Korean Journal of Microbiology
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• v.30 no.1
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• pp.8-14
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• 1992

Nucleotide Sequence of phnE Gene Encoding Extradiol Dioxygenase fromPseudomonas sp. Strain DJ77Kim, Young-Chang'.", Myeong-Su Shin1, Kil-Sang Younl, Young-Soon Park1, andUg-Hyeon Kim'.' (Department of Microbiology, C'hungbuk National University.Cheongju 360-763, KOREA. and 'Research Center for Molecular Microbiology,Seoul National University)nal University)

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.232-236
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• 1997

It is known that septin gene encodes the filament in Saccharomyces cerevisiae and it has importants roles in bud formation and cytokinesis. Four septin genes have been cloned in S. cerevisiae and it was found in Drosophila melanogaster and mouse. In this study, we cloned the septin gene in Schizosaccahromyces pombe by use of PCR technique. The septin gene in S. pombe has an 1,143 bp open reading frame and encodes a protein of 380 amino acids with a molecular weight of 42 kd. Comparison of the predicted amano acid sequences between the septin gene in S. pombe and CDC12 gene in S. cerevisiae reveals the 51.8% of simility.

• Journal of Life Science
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• v.18 no.12
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• pp.1764-1770
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• 2008

The goal of this study is to increase production of astaxanthin in recombinant Escherichia coli by engineered isoprenoid pathway. We have previously reported structural and functional analysis of the astaxanthin biosynthesis genes from a marine bacterium, Paracoccus haeundaensis. The carotenoid biosynthesis gene cluster involved in astaxanthin production contained six carotenogenic genes (crtW, crtZ, crtY, crtI, crtB, and crtE genes) and recombinant E. coli harboring six carotenogenic genes from P. haeundaensis produced 400 ${\mu}g$/g dry cell weight (DCW) of astaxanthin. In order to increase production of astaxanthin in recombinant E. coli, we have cloned 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (lytB), farnesyl diphosphate (FPP) synthase (ispA), and isopentenyl (IPP) diphossphate isomerase (idi) in the isoprenoid pathway from E. coli and coexpressed these genes in recombinant E. coli harboring the astaxanthin biosynthesis genes. This engineered E. coli strain containing both isoprenoid pathway gene and astaxanthin biosynthesis gene cluster produced 1,200 ${\mu}g$/g DCW of astaxanthin, resulting 3-fold increased production of astaxanthin.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.810-820
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• 2016

This study is focused on the investigation of the genes which are induced by various stresses of the halophyte Salicornia herbacea. One of the factors influencing in the germination of Salicornia herbacea is salt stress. The highest germination rate was found in the condition without NaCl, and the upper limit of the NaCl concentration for the germination of Salicornia herbacea was 7%. The optimal temperature of $20^{\circ}C$showed a germination rate of 98%. Among genes induced by stress the 2CysPrx gene was cloned and analyzed for this study. The 2CysPrx gene has two cysteine conserved residues and is composed of 275 amino acids with molecular weight of 30.1kDa. The 2CysPrx gene appeared to be one copy in the genome and consists of 6 introns and 7 exons. Quantitative real-time PCR revealed that the highest transcription rate induced by NaCl and $H_2O_2$ appeared to be at the concentration of 3.5% NaCl and 40mM $H_2O_2$, respectively. The amount of transcript induced by high temperature($40^{\circ}C$) and $75{\mu}M$ of ABA was respectively highest. The gene at low temperature ($4^{\circ}C$) appeared not to be expressed. We are conducting to clone other peroxyredoxin genes induced by various environmental stresses.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.155-161
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• 2017

A gene coding for the xylanase predicted from the partial genomic sequence of Paenibacillus woosongensis was cloned by PCR amplification and sequenced completely. This xylanase gene, designated xyn11B, consisted of 1,071 nucleotides encoding a polypeptide of 356 amino acid residues. Based on the deduced amino acid sequence, Xyn11B was identified to be a modular enzyme, including a single carbohydrate-binding module besides the catalytic domain, and was highly homologous to xylanases belonging to glycosyl hydrolase family 11. The SignalP4.1 server predicted a stretch of 26 residues in the N-terminus to be the signal peptide. Using DEAE-Sepharose and Phenyl-Sepharose column chromatography, Xyn11B was partially purified from the cell-free extract of recombinant Escherichia coli carrying a copy of the P. woosongensis xyn11B gene. The partially purified Xyn11B protein showed maximal activity at $50^{\circ}C$ and pH 6.5. The enzyme was more active on arabinoxylan than on oat spelt xylan and birchwood xylan, whereas it did not exhibit activity towards carboxymethylcellulose, mannan, and para-nitrophenyl-${\beta}$-xylopyranoside. The activity of Xyn11B was slightly increased by $Ca^{2+}$ and $Mg^{2+}$, but was significantly inhibited by $Cu^{2+}$, $Ni^{2+}$, $Fe^{3+}$, and $Mn^{2+}$, and completely inhibited by SDS.