• 한국미생물·생명공학회지
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• 제20권2호
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• pp.129-135
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• 1992

본 연구에서는 Serratia marcescens ATCC 27117 균주로부터 키나아제 유전자를 대장균으로 클로닝 하고 발현시켰다. pUC 19 플라스미드를 이용하여 S.marcescens의 genomic library를 만들고 팽화된 키틴이 포함된 한천배지에서 키티나아제 활성을 가지는 클론을 선별하였다. 약 1x10 transformant들 중에서 키티나아제 활성을 보이는 하나의 클론을 선발하였으며 이것은 pUC 19 플라스미드속에 8.9Kb 염색체 DNA 삽입단편을 가지고 있었다.

• BMB Reports
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• 제37권4호
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• pp.445-453
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• 2004

We identified apoptosis as being a significant mechanism of toxicity following the exposure of HeLa cell cultures to abrin holotoxin, which is in addition to its inhibition of protein biosynthesis by N-glycosidase activity. The treatment of HeLa cell cultures with abrin resulted in apoptotic cell death, as characterized by morphological and biochemical changes, i.e., cell shrinkage, internucleosomal DNA fragmentation, the occurrence of hypodiploid DNA, chromatin condensation, nuclear breakdown, DNA single strand breaks by TUNEL assay, and phosphatidylserine (PS) externalization. This apoptotic cell death was accompanied by caspase-9 and caspase-3 activation, as indicated by the cleavage of caspase substrates, which was preceded by mitochondrial cytochrome c release. The broad-spectrum caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (zVAD-fmk), prevented abrin-triggered caspase activation and partially abolished apoptotic cell death, but did not affect mitochondrial cytochrome c release. These results suggest that the release of mitochondrial cytochrome c, and the sequential caspase-9 and caspase-3 activations are important events in the signal transduction pathway of abrin-induced apoptotic cell death in the HeLa cell line.

• 미생물학회지
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• 제24권1호
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• pp.18-23
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• 1986

Breνibacterium divaricatum FERM 5948 균주로 부터 Bdi I 제한효소를 ammonium sulfate분획, DEAE-cellulose chroma tograph 그리고 heparin agarose chromatograph 방법을 거쳐 부분정제하여 그 효소적 특성을 관찰하였다. 분리한 Bdi I 제한효소는 pBR 322와 ${\lambda}$ DNA를 이용하여 인지부위를 알아본 결과 5' ATCGAT3'을 인지하는 Cia I과 isoschizomer였다. 또한 CIa I 으로 자른 ${\lambda}$ DNA가 Bdi I 으로 자른 pBR 322에 클로닝 됨으로 보아 Bdi I 제한효소는 T와 C사이를 잘라(5' AT CGAT 3') 5' pGG를 가지는 cohesive end로 만듬을 알 수 있었다. 이 효소의 최적활성온도는 $37^{\circ}C$ 였고 50 - 100 mM의 NaCl 농도에서 활성이 높았으여 150 mM이상의 농도에서는 활성이 저해되었다.

• Journal of Photoscience
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• 제9권3호
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• pp.49-50
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• 2002

N-Nitrosoproline(NPRO) is endogenously formed from proline and nitrite. NPRO has been reported to be nonmutagenic and noncarcinogenic. In this study, we have detected the direct mutagenicity of NPRO with UVA and UVB towards S. typhimurium. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a mutagenic lesion, was observed in calf thymus DNA treated with NPRO plus simulated sunlight. Furthermore, the treatment with NPRO and sunlight induced single strand breaks in the superhelical replicative form of phage M13mp2 DNA. An analysis using scavengers suggested that both reactive oxygen species and NO radical mediate the strand breaks. The formation of nitric oxide was observed in NPRO solution irradiated with UVA. The co-mutagenic and co-toxic actions of NPRO and sunlight merit attention as possible mechanisms increasing the carcinogenic risk from UVA irradiation.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1919-1926
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• 2020

CRISPR interference (CRISPRi) has been developed as a transcriptional control tool by inactivating the DNA cleavage ability of Cas9 nucleases to produce dCas9 (deactivated Cas9), and leaving dCas9 the ability to specifically bind to the target DNA sequence. CRISPR/Cas9 technology has limitations in designing target-specific single-guide RNA (sgRNA) due to the dependence of protospacer adjacent motif (PAM) (5'-NGG) for binding target DNAs. Reportedly, Cas9-NG recognizing 5'-NG as the PAM sequence has been constructed by removing the dependence on the last base G of PAM through protein engineering of Cas9. In this study, a dCas9-NG protein was engineered by introducing two active site mutations in Cas9-NG, and its ability to regulate transcription was evaluated in the gal promoter in E. coli. Analysis of cell growth rate, D-galactose consumption rate, and gal transcripts confirmed that dCas9-NG can completely repress the promoter by recognizing DNA targets with PAM of 5'-NGG, NGA, NGC, NGT, and NAG. Our study showed possible PAM sequences for dCas9-NG and provided information on target-specific sgRNA design for regulation of both gene expression and cellular metabolism.

• BMB Reports
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• 제56권2호
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• pp.102-107
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• 2023

Genome editing using CRISPR-associated technology is widely used to modify the genomes rapidly and efficiently on specific DNA double-strand breaks (DSBs) induced by Cas9 endonuclease. However, despite swift advance in Cas9 engineering, structural basis of Cas9-recognition and cleavage complex remains unclear. Proper assembly of this complex correlates to effective Cas9 activity, leading to high efficacy of genome editing events. Here, we develop a CRISPR/Cas9-RAD51 plasmid constitutively expressing RAD51, which can bind to single-stranded DNA for DSB repair. We show that the efficiency of CRISPR-mediated genome editing can be significantly improved by expressing RAD51, responsible for DSB repair via homologous recombination (HR), in both gene knock-out and knock-in processes. In cells with CRISPR/Cas9-RAD51 plasmid, expression of the target genes (cohesin SMC3 and GAPDH) was reduced by more than 1.9-fold compared to the CRISPR/Cas9 plasmid for knock-out of genes. Furthermore, CRISPR/Cas9-RAD51 enhanced the knock-in efficiency of DsRed donor DNA. Thus, the CRISPR/Cas9-RAD51 system is useful for applications requiring precise and efficient genome edits not accessible to HR-deficient cell genome editing and for developing CRISPR/Cas9-mediated knockout technology.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.183-183
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• 1996

Bacteriophage T4 endonuclease V initiates the repair of ultraviolet (UV)-induced pyrimidine dimer photoproducts in duplex DNA. The mechanism of DNA strand cleavage involves four sequential stens: linear diffusion along dsDNA, pyrimidine dimer-specific binding,l pyrimidine dimer-DNA glycosylase activity, and Af lyase activity. Although crystal structure is known for this enzyme, solution structure has not been yet known. In order to elucidate the solution structure of this enzyme NMR spectroscopy was used. As a basis for the NMR peak assignment of the protein, HSQC spectrum was obtained on the uniformly $\^$15/N-labeled T4 endonuclease V. Each amide peak of the spectrum were classified according to amino acid spin systems by interpreting the spectrum of $\^$15/N amino acid-specific labeled T4 endonuclease V. The assignment was mainly obtained from three-dimensional NMR spectra such as 3D NOESY-HMQC, 3D TOCSY-HMQC. These experiments were carried out will uniformly $\^$15/N-labeled sample. In order to assign tile resonance of backbon atom, triple-resonance theree-dimensional NMR experiments were also performed using double labeled($\^$15/N$\^$13/C) sample. 3D HNCA, HN(CO)CA, HNCO, HN(CA)HA spectra were recorded for this purpose. The results of assignments were used to interpret the interaction of this enzyme with DNA. HSQC spectrum was obtained for T4 endonuclease V with specific $\^$15/N-labeled amino acids that have been known for important residue in catalysis. By comparing the spectrum of enzyme*DNA complex with that of the enzyme, we could confirm the important role of some residues of Thr, Arg, Tyr in activity. The results of assignments were also used to predict the secondary structure by chemical shift index (CSI).

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.74-74
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• 2018

Abeliophyllum distichum is Korea Endemic Plants and its genetic resources found from Korea only. Bioactivities of A. distichum such as antioxidant, anti-cancer, and anti-inflammatory studies have been proved through many researches. Whereas, there are no studies on the biological activity of its callus extracts. In this study, we investigated the antioxidant activities of callus extracts derived from A. distichum and its inhibitory effect on oxidative DNA damage. The antioxidant activities were assessed using radical scavenging assays with DPPH, ABTS, and reducing power assay and the inhibitory effects on oxidative DNA damage were measured using ${\varphi}-174$ RF I plasmid DNA cleavage assay. In addition, callus extracts derived from A. distichum showed high antioxidant acitivties and no cytotoxicity in NIH/3T3. Also, it has significantly suppressed expression of ${\gamma}$-H2AX and p53 protein and mRNA levels in NIH/3T3 cells exposed to oxidative stress. Therefore, the callus extracts derived from A. distichum has potential antioxidant activity that can provide protective effects against the oxidative DNA damage caused by free radicals. This study suggest that it is valuable as cosmetics and medicine for antioxidant and cancer preventive materials.

• 생명과학회지
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• 제19권9호
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• pp.1209-1217
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• 2009

많은 암세포에 선택적 세포독성을 나타내는 TNF-related apoptosis-inducing ligand (TRAIL)는 유효한 항암제로서 사용될 수 있지만, TRAIL에 내성을 나타내는 암세포에는 TRAIL-sensitization의 방법이 필요하다. 사람 대장암 세포인 KMl2 세포도 TRAIL에 내성을 나타낸다. 본 연구에서는 KMl2세포의 TRAIL 내성에 대한 새로운 표적 분자의 발굴과 이를 토대로 한 새로운 내성극복 방법을 연구하였다. 새로운 TRAIL sensitizer로서 quercetin을 발굴하고, 이를 KMl2세포에 TRAIL과 병용 처리하여 TRAIL의 효과증강을 시도하였다. KMl2세포에서 quercetin은 c-FLTP의 발현을 감소시키고, DNA-PK/Akt 신호전달경로를 억제하므로서, death receptors (DR4/DR5) 발현을 증강시켰다. 또한 caspases (caspase 3, -8 및 -9)활성 증강과 PARP cleavage, 이에 따른 Bax의 발현을 증강시키는 기전으로 TRAIL에 의한 apoptosis를 증대시키는 활성이 있음을 밝혔다. 즉 quercetin이 KMl2세포의 TRAIL-sensitization에 사용될 수 있음을 제시하였다. 이러한 연구 결과는 대장암의 치료 시 TRAIL과 quercetin병용하므로서 치료 효과를 높일 수 있는 새로운 약제 병용 방법을 제시하였고, 다른 TRAIL 내성 종양에 응용 될 수 있음을 시사하였다.

• 한국미생물·생명공학회지
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• 제35권2호
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• pp.104-111
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• 2007

본 연구에서는 단일 탄소원과 질소원으로 aniline을 이용하는 것으로 보고된 바 있는 Bukholderia sp. HY1과 Deiftia sp. HY99로부터 aniline의 첫 번째 분해 단계에 관련된 aniline dioxygenas의 위치를 확인하고 그 유전자를 클로닝하여 아미노산 서열을 결정하고 비교하였다. 한 개 이상의 플라스미드 DNA를 포함하고 있을 것으로 조사된 B.a sp. HY1에서 유래된 플라스미드의 curing 실험을 통해, B. sp. HY1의 aniline oxygenase는 플라스미드가 아닌 염색체 DNA에 존재하는 것으로 확인되었다. B. sp. HY1과 D. sp. HY99에서 유래된 aniline dioxygenase small subunit는 146개 아미노산을 기준으로 약 79%의 상동성을 보였다. 특히, B. sp. HY1으로부터 얻어진 ado2는 aniline dioxygenase small subunit의 terminal dioxygenase에 속하는 것으로 Frateuria sp. ANA-18의 tdnA2와 99%, 그리고 Delftia sp. HY99의 ado2는 Delftia sp. AN3의 danA2와 99% 이상의 아미노산 상동성을 나타내었다. 또한 본 연구에서 두 균주에서 얻어진 catechol oxygenase의 아미노산 서열분석을 통해 B. sp. HY1은 catechol 1,2-dioxygenase에 의해 ortho pathway를 D. sp. HY99는 catechol 2,3-dioxygenase에 의해 meta pathway를 운영할 것이라는 이전 보고를 강력하게 뒷받침해 주었다.