• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1885-1888
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• 2005

• BMB Reports
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• 제31권4호
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• pp.307-327
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• 1998

Cytochrome c peroxidase (CcP) is a yeast mitochondrial enzyme which catalyzes the reduction of hydrogen peroxide to water using two equivalents of ferrocytochrome c. The CcP/cytochrome c system has many features which make it a very useful model for detailed investigation of heme protein structure/function relationships including activation of hydrogen peroxide, protein-protein interactions, and long-range electron transfer. Both CcP and cytochrome c are single heme, single subunit proteins of modest size. High-resolution crystallographic structures of both proteins, of one-to-one complexes of the two proteins, and a number of active-site mutants are available. Site-directed mutagenesis studies indicate that the distal histidine in CcP is primarily responsible for rapid utilization of hydrogen peroxide implying significantly different properties of the distal histidine in the peroxidases compared to the globins. CcP and cytochrome c bind to form a dynamic one-to-one complex. The binding is largely electrostatic in nature with a small, unfavorable enthalpy of binding and a large positive entropy change upon complex formation. The cytochrome c-binding site on CcP has been mapped in solution by measuring the binding affinities between cytochrome c and a number of CcP surface mutations. The binding site for cytochrome c in solution is consistent with the crystallographic structure of the one-to-one complex. Evidence for the involvement of a second, low-affinity cytochrome c-binding site on CcP in long-range electron transfer between the two proteins is reviewed.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.823-826
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• 2001

In the initial process of photosynthesis, a biological electron transfer system, photoelectric conversion occurs and then long-range electron transfer takes place very efficiently in one direction through the biomolecules. The metal/insulator/metal structured device consisting of GFP, viologen, cytochrome c hetero-thin film was presented based on the biomimesis. GFP, viologen, and cytochrome c was used as an electron sensitizer, a mediator, and an electron acceptor. Cytochrome c molecules and viologen molecules were deposited by Langmuir-Blodgett (LB) technique, and GFP molecules were adsorbed by self-assembly method (SAM). Surface morphology of hetero-thin film was analyzed by scanning tunneling microscopy (STM). Local photoswitching effects of a proposed photodiode were verified by current-voltage measurements using hybrid STM/I-V measurement system.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.18-18
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• 2005

Photoinduced electron transport process in nature such as photoelectric conversion and long-range electron transfer in photosynthetic organisms are known to occur not only very efficiently but also unidirectionally through the functional groups of biomolecules. The basic principles in the development of new functional devices can be inspired from the biological systems such as molecular recognition, electron transfer chain, or photosynthetic reaction center. By mimicking the organization of the biological system, molecular electronic devices can be realized $artificially^{1)}$. The nano-fabrication technology of biomolecules was applied to the development of nano-protein chip for simultaneously analyzing many kinds of proteins as a rapid tool for proteome research. The results showed that the self-assembled protein layer had an influence on the sensitivity of the fabricated bio-surface to the target molecules, which would give us a way to fabricate the nano-protein chip with high sensitivity. The results implicate that the biosurface fabrication using self-assembled protein molecules could be successfully applied to the construction of nanoscale bio-photodiode and nano-protein chip based on electrical detection.

• Bulletin of the Korean Chemical Society
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• 제17권7호
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• pp.616-621
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• 1996

The transfer of excitation energy from solvent to solute in polystyrene films doped with 2-(2'-hydroxyphenyl)benzothiazole (HBT) which undergoes intramolecular proton transfer in excited electronic state has been studied by employing steady state and time-resolved fluorescence measurements. The degree of Forster overlap between donor and acceptor molecule in this system is estimated to be moderate. Energy transfer efficiency increases with solute concentration at low concentration range and levels off at high concentration. It is observed that the excimer form of polystyrene is largely involved in energy transfer process. Photostability of HBT in polystyrene to UV light is also investigated to get insight into the long wavelength absorption band of HBT which was observed upon electron radiation.

• 한국염색가공학회지
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• 제26권4호
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• pp.305-310
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• 2014

In this study, we presented a newly synthesized pyrene-naphthalene diimide(NDI)-pyrene triad. The optical and structural properties were examined using various characterization techniques. A donor-acceptor-donor triad molecule exhibited a strong charge transfer, though there existed neither intramolecular nor intermolecular hydrogen bonding sites, due to the formation of preferential complementary complex between pyrene and NDI. Powder XRD measurement revealed a sharp and distinctive X-ray patterns, indicating the presence of microcrystalline-like structure. POM images showed anisotropic fingerprint texture similar to that of cholesteric phase, and SEM images showed numerous columnar structures with length of 1 to $10{\mu}m$. Above observation clearly demonstrated that ${\pi}$-complementary NDI-pyrene interactions in the traid was strong enough to form columnar aggregates in the long range.

• 생명과학회지
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• 제14권5호
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• pp.752-760
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• 2004

Nitrogenase 촉매에서 Fe-단백질을 포함하는 [4Fe-4S] 클라스터의 기능은 기질의 결합과 환원 자리를 포함하는 MoFe-단백질로 핵산 의존 전자 주개로 작용하는 것이다. 이러한 방법의 Fe-단백질의 기능은 Mofe-단백질과 상호작용을 위해 적합한 구조를 갖추며 전자 전달을 위한 추진력을 제공하기 위해 산화 환원 퍼텐셜을 변화시키는 능력에 의존한다. Nitrogenase Fe-단백질에 MgADP가 결합한 (혹은 떨어진) 구조적 정보는 핵산 결합 자리로부터 MoFe-단백질과의 결합력을 조절하기 위한 장거리 상호작용 메커니즘을 제시한다. 스위치 I과 II의 두 가지 경로가 뉴클레오티드의 신호전달 메커니즘을 담당한다. MgADP가 결합된 Fe-단백질의 구조는 Fe 단백질이 핵산과 결합할 때 관찰되는 [4Fe-4S] 클라스터의 생물리학적 특성 변화의 기초를 제공한다. 스위치, I과 II의 핵산 의존 신호전달 경로에서 특정 아미노산이 치환된 nitrogenase Fe-단백질의 구조들이 X-선 회절법에 의해서 결정되었다. 이들 경로는 아미노산 치환 연구, 구조 분석, 유사한 핵산 의존 신호전달 경로에 이용된 다른 단백질 등에 의해서도 분석되었다. 이들 경로가 거대분자 착물 형성과 분자간 전자 전달을 위한 MgADP 결합과 가수분해의 신호전달 경로로의 타당성이 조사되었다. 이러한 결과는 nitrogenase Fe 단백질과 MoFe-단백질 착물에서 Fe-단백질의 변이와 상호작용의 생물리학적 및 생화학적 특성을 위한 기초적 자료를 제공할 것이다.

• 한국식품조리과학회지
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• 제25권2호
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• pp.252-259
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• 2009

본 연구에서는 식품의 곰팡이 초기오염 검출에 사용할 수 있는 ergosterol 분석용 바이오센서를 개발하고자 $MWNT-NH_2$ 유리탄소전극을 제작하고, cholesterol oxidase의 고정화를 통해 효소반응기를 제작하여, 바이오센서의 전기 화학적 ergosterol 검출장치를 구성하였다. FT-IR을 통해 MWNT에 기능기가 잘 도입되었음을 확인하였고, cholesterol oxidase 효소 고정화 시 coupling efficiency는 99% 이었다. 제작한 $MWNT-NH_2$ 유리탄소전극의 $H_2O_2$ 용액에 대한 농도별 전류를 분석한 결과 $1{\times}10^{-5}{\sim}8{\times}10^{-5}$ M 농도에서 우수한 선형관계를 나타내었고 검출한계는 $10^{-7}$ M이었다. 본 연구에서 제작한 ergosterol 센서를 이용하여 ergosterol에 대한 반응을 측정한 결과 $1.0{\times}10^{-6}{\sim}1.0{\times}10^{-5}$ M의 농도에서 좋은 선형관계를 나타내어 고감도로 ergosterol을 정량할 수 있는 것으로 확인되어 식품의 곰팡이 오염을 확인하는데 유용하게 사용될 수 있을 것으로 보인다.