• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.413-417
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• 2005

Fluorescence of green fluorescent protein mutant, 2-5 GFP is observed during denaturation by guanidine. The fluorescence intensity decreases exponentially but the fluorescence lifetime does not change during denaturation. The fluorescence lifetime of the denatured protein is shorter than that of native form. As the protein structure is modified by guanidine, solvent water molecules penetrate into the protein barrel and protonate the chromophore to quench fluorescence. Most fluorescence quenchers do not affect the fluorescence of native form but accelerate the fluorescence intensity decay during denaturation. Based on the observations, a simple model is suggested for the structural change of the protein molecule during denaturation.

• 한국광학회지
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• 제35권1호
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• pp.30-34
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• 2024

실크 단백질과 녹색 형광 단백질을 결합한 순수 단백질 기반 녹색 형광체의 구현과, 산화티타늄 나노 입자에 의한 형광 증폭 현상을 보고한다. 실크 단백질은 인간에게 다양한 이점을 제공하는 소재로서, 다양한 마이크로/나노 구조 형성 가능성과 투명한 성질을 가지고 있어 광학소재로서의 활용 가능성 또한 높다. 본 연구에서 제작한 소재는 강한 녹색 형광을 띠고 있으며, 산화티타늄 나노 입자에 의해 녹색 형광이 7.5배 증폭되는 것을 확인하였다.

• BMB Reports
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• 제35권6호
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• pp.562-567
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• 2002

In order to find the cellular interaction factors of the Heliothis armigera nuclear polyhedrosis virus capsid protein VP39, a Heliothis armigera cell cDNA library was constructed. Then VP39 was used as bait. The host actin gene was isolated from the cDNA library with the yeast two-hybrid system. This demonstrated that VP39 could interact with its host actin in yeast. In order to corroborate this interaction in vivo, the vp39 gene was fused with the green fluorescent protein gene in plasmid pEGFP39. The fusion protein was expressed in the Hz-AM1 cells under the control of the Autographa californica multiple nucleopolyhedrovirus immediate early gene promoter. The host actin was labeled specifically by the red fluorescence substance, tetramethy rhodamine isothicyanete-phalloidin. Observation under a fluorescence microscopy showed that VP39, which was indicated by green fluorescence, began to appear in the cells 6 h after being transfected with pEGFP39. Red actin cables were also formed in the cytoplasm at the same time. Actin was aggregated in the nucleus 9 h after the transfection. The green and red fluorescence always appeared in the same location of the cells, which demonstrated that VP39 could combine with the host actin. Such a combination would result in the actin skeleton rearrangement.

• KSBB Journal
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• 제14권3호
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• pp.377-379
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• 1999

CHO/dhfr- 세포에 대해 LipofectAmine$^{TM}$을 이용한 유전자 이입 효율을 증가시키기 위하여 지질과 DNA의 최적 농도를 구하였다. Reporter 유전자로서 GFP 유전자를 이용하였으며, 여러 농도의 지질 DNA로 유전자 이입된 각 세포군에서 나타나는 green fluorescence intensity를 FACS 분석함으로써 유전자 이입 효율을 정량화 할 수 있었다. 그 결과 24-well plate에서 $2.0{\mu}L$LipofectAmine$^{TM}$과 $0.4{\mu}g$ DNA를 조합하여 사용했을 때 최적의 유전자 이입 효율이 나타남을 알 수 있었다. 또한, GFP는 유전자 이입 최적화를 수행하는 데에 여러가지 면에서 유용한 수단이 될 수 있음을 확인할 수 있었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.475-477
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• 1997

We have analyzed the fluorescence image obtaining from green fluorescence protein (GFP). In order to monitor the fluorescence of specific gene, we used the amyloid precursor protein promoter which has been known to act as a major role in the development of Alzheimer's disease. The promoter from - 3.0 kb to + 100 base pair was inserted into the gene expression monitoring GFP vector purchased from Clontech. This construct was transfected into the PC 12 and fibroblast cells and the fluorescence image was captured by two kinds of methods. One is using cheaper CCD camera and other is SIT-CCD camera. or the higher sensitivity of the fluorescence image, we developed the multiple image grabbing program. As a results, the fluorescence image by conventional CCD camera have the similar sensitivity compared with that of the SIT-camera by applying the multiple image grabbing programs. By this system. it will be possible to construct the fluorescence monitoring system with lower cost. And gene expression in real time by fluorescence image will be possible without changing the fluorescence images.

• KSBB Journal
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• 제28권5호
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• pp.310-314
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• 2013

Antifreeze peptide from Myoxocephalus octodecemspinosus was overexpressed and purified in Escherichia coli. Green fluorescence protein-AFP chimera was constructed by integrating gfp and afp genes. Produced GFP-AFP chimera protein was purified using polyhistidine tag which was inserted at C-terminus. By addition of GFP-AFP chimera protein, freezing point of elution buffer was decreased from $-13^{\circ}C$ to $-20^{\circ}C$. This result suggested that GFP-AFP chimera can be considered as a potential candidate of novel inhibitor for gas hydrates.

• 생명과학회지
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• 제17권2호통권82호
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• pp.293-297
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• 2007

형광단백질 (green fluorescent protein, GFP)은 생물공정을 살피데 지표 단백질로 유용하게 사용이 된다. 본 연구에서는 쌀세포에서 외래 단백질의 발현양상을 관찰하기 위해서, 표지 단백질로 GFP를 형질전환 후 이것에서 유도된 현탁세포에서 GFP의 발현 양상을 관찰하였다. 형질전환시 GFP의 발현을 위한 프로모터로 RAmysE를 사용하였으며 이것은 배양액 중에서 당이 고갈되었을 때 강력히 작동된다. 그래서 본 연구에서는 배양액 중에 다양한 슈크로오스 농도로 쌀세포를 배양하여 세포의 성장양태 및 GFP의 발현양에 미치는 영향을 관찰한 결과 세포의 성장은 12%의 당농도에서 7.06g/L로 최적이였으며 GFP는 당을 가장 적게 사용한 3%에서 최적임을 알 수가 있었다. 이것은 세포의 성장과 GFP의 생산에 사용된 당이 반대로 영향을 미침을 알 수가 있었으며 향후 최적의 대량배양을 위해서는 세포의 성장과 산물의 생산시기를 분리한 이단계 배양법이 필요함을 암시한다.

• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.404-409
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• 2004

We fabricated photo-sensor for fluorescence detection in LOC. LOC is high throughput screening system. Our LOC screens biochemical reaction of protein using the immunoassay, and converts biochemical reaction into electrical signal using LIF(Laser Induced Fluorescence) detection method. Protein is labeled with rhodamine intercalating dye and finger PIN photodiode is used as photo-sensor We measured fluorescence emission of rhodamine dye and analyzed tendency of fluorescence detection, according to photo-sensor size, light intensity, and rhodamine concentration. Detection current was almost linearly proportional to two parameters, intensity and concentration, and was inversely proportional to photo-sensor size. Integrated LOC consists of optical-filter deposited photo-sensor and PDMS microchannel detected 50 (pg/${mu}ell$) rhodamine. For integrated LOC including light source, we used green LED as the light source and measured emitted fluorescence.

• 산업기술연구
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• 제29권B호
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• pp.115-119
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• 2009

Green fluorescent protein (GFPuv) was displayed on the surface of ethanol-producing bacteria Zymomonas mobilis using N-terminal domain of ice nucleation protein (INP) as an anchoring motif. To evaluate the ice nucleation protein as plausible anchor motif in Z. mobilis, GFPuv gene was subcloned into Zymomonas expression vector yielding pBBR1MCS-3/pPDC/INPN/GFPuv plasmid., INP-GFPuv fusion protein was expressed in Z. mobilis and its fluorescence was verified by confocal microscopy. The successful display of GFPuv on Zymomonas mobilis suggest that INP anchor motif could be used for future fusion partner in Z. mobilis strain improvement.

• Journal of Microbiology and Biotechnology
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• 제22권9호
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• pp.1271-1278
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• 2012

Genetic fusion of two proteins frequently induces beneficial effects to the proteins, such as increased solubility, besides the combination of two protein functions. Here, we study the effects of the bacterial surface layer protein SgsE from Geobacillus stearothermophilus NRS 2004/3a on the folding of a C-terminally fused enhanced green fluorescent protein (EGFP) moiety. Although GFPs are generally unable to adopt a functional confirmation in the bacterial periplasm of Escherichia coli cells, we observed periplasmic fluorescence from a chimera of a 150-amino-acid N-terminal truncation of SgsE and EGFP. Based on this finding, unfolding and refolding kinetics of different S-layer-EGFP chimeras, a maltose binding protein-EGFP chimera, and sole EGFP were monitored using green fluorescence as indicator for the folded protein state. Calculated apparent rate constants for unfolding and refolding indicated different folding pathways for EGFP depending on the fusion partner used, and a clearly stabilizing effect was observed for the SgsE_C fusion moiety. Thermal stability, as determined by differential scanning calorimetry, and unfolding equilibria were found to be independent of the fused partner. We conclude that the stabilizing effect SgsE_C exerts on EGFP is due to a reduction of degrees of freedom for folding of EGFP in the fused state.