• Mass Spectrometry Letters
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• 제6권3호
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• pp.80-84
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• 2015

Here, we demonstrate the use of MALDI-TOF as a fast and simple analytical approach to evaluate the DNA-binding capability of various peptides. Specifically, by varying the amino acid sequence of the peptides consisting of lysine (K) and tryptophan (W), we identified peptides with strong DNA-binding capabilities using MALDI-TOF. Mass spectrometric analysis reveals an interesting novel finding that lysine residues show sequence selective preference, which used to be considered as mediator of electrostatic interactions with DNA phosphate backbones. Moreover, tryptophan residues show higher affinity to DNA than lysine residues. Since there are numerous possible combinations to make peptide oligomers, it is valuable to introduce a simple and reliable analytical approach in order to quickly identify DNA-binding peptides.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1183-1189
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• 2021

Autodisplay of a multimeric protein complex on a cell surface is limited by intrinsic factors such as the types and orientations of anchor modules. Moreover, improper folding of proteins to be displayed often hinders functional cell surface display. While overcoming these drawbacks, we ultimately extended the applicability of the autodisplay platform to the display of a protein complex. We designed and constructed a cell surface attachment (CSA) system that uses a non-covalent protein-protein interaction. We employed the high-affinity interaction mediated by an orthogonal cohesin-dockerin (Coh-Doc) pair from Archaeoglobus fulgidus to build the CSA system. Then, we validated the orthogonal Coh-Doc binding by attaching a monomeric red fluorescent protein to the cell surface. In addition, we evaluated the functional anchoring of proteins fused with the Doc module to the autodisplayed Coh module on the surface of Escherichia coli. The designed CSA system was applied to create a functional attachment of dimeric α-neoagarobiose hydrolase to the surface of E. coli cells.

• BMB Reports
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• 제28권6호
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• pp.552-555
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• 1995

Treatment of microsomal vesicles isolated from etiolated Pisum sativum L cv. Alaska epicotyl tissue with agents inhibiting protein dephosphorylation, namely NaF and/or ATP, resulted in increased binding of the phytotropin NPA to the putative auxin efflux carriers localized on the plasma membrane. The phytotropin effect was especially conspicuous if the vesicles were simultaneously treated with Triton X-100. Kinetic analysis of the binding indicated the existance of two distinct sites for NPA, each having different affinities. Increased binding of the phytotropin to the membrane where protein dephosphorylation was inhibited was attributable to the increased ligand affinity of both sites. Treatment of tissue segments with flubride was found to enhance in vivo auxin transport. Implications of covalent modification of the auxin efflux carrier complex for the regulation of membrane transport of auxin molecules are discussed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 International Symposium
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• pp.111-124
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• 2003

기존의 오염물질을 제거하는 많은 화학적-물리적 정화 방법은 고비용과 오랜 시간을 요구하는 처리 과정 등의 단점을 갖고 있는 경우가 많았다. 따라서 흙과 수(水)환경내로 유입된 오염물질을 빠른 시간 내에 제거 할 수 있는 대안이 요구 되었다. 흙에 유출된 화합 물질 중 상당양은 흙에 의해 격리, 구속되고 이로 인해 일단 구속된 오염물질은 물과 유기 용매에 의해서도 잘 추출되지 않는 것으로 보고 되고 있다. 이러한 흙에 의한 오염물질의 비유동성(immobilization) 과정은 오염물질의 제거 기술의 대안으로 평가 될 수 있다. 기존 연구자들의 연구 결과, 화학적 혹은 물리적 반응 작용을 통해 오염물질을 흙을 구성하는 물질에 구속할 수 있음이 증명되었다. 이러한 과정 중 환경적 측면에서 볼 때, 화학적 반응이 더 우수하다 할 수 있다. 이는 강한 공유결합(covalent bonds)으로 연결될 경우 미생물의 활동이나 화학 처리로도 이를 분리하기 어렵기 때문이다. 리그닌(lignin) 분해에서 발생하는 휴믹(humic) 물질 등이 안정 된 화학적 연결을 통해 흙 매질 내에 오염물질과 결합하는 대표적 물질이다. 인위적으로 제조된 많은 화학물질은 자연적에서 발생하는 휴민산 발생원(humic acid precursors)과 닮았다. 따라서 화학물은 부식 과정(humifications process)동안 부식토(humus) 내로 병합(incorporate)되어 진다. 일단 이렇게 구성된 결합체는 생물체와 오염물질과의 반응을 방지하여 오염물질로 인한 생물체로의 독성을 감소시키는 역할을 하게 된다. 본 논문에서는 이러한 흙의 유기물(organic matter)와 오염물질과의 결합체에 대한 평가로서 다음의 항목에 대한 고찰이 이루어져야 함을 강조하였다. (a)결합체에서 생물체(biota)와의 반응에 의해 오염물질은 감소되는가\ulcorner (b) 모(parent) 화합물과 비교하여 복합체 생성물(complexed products)이 얼마나 덜 유독한가\ulcorner 그리고 (c)지하수 오염이 오염물질의 유동성 구속에 의해 얼마나 감소되는지\ulcorner

• KSBB Journal
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• 제16권2호
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• pp.115-122
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• 2001

Molecular imprinting has now been established as a technique which allows the creation of tailor-made binding sites for many classes of compounds. MIPs were prepared by covalent and non-covalent chemical bonding systems, by interactions between functional monomer and template. The shape of MIP is divided to particle and membrane. MIP membranes can be prepared by surface imprinting, in-situ polymerization, wet phase inversion and the dry phase inversion method. MIPs have been mainly used for analytical separation and biosensor systems to separate and detect chiral compounds and materials with similar structures. However the application of MIP by the chemical industries is still in its infancy stages. This review summarizes the preparative characteristics and applications of MIP with respect to chiral separations and biosensors.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.689-692
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• 2001

An imprinting technique with labile covalent interactions has been developed in the design of new polymer catalysts. The template monomer 2 was prepared and copolymerized with DVB or EDMA to provide the polymer with a cavity having the shape of th e transition state of the reaction as well as binding sites for the substrate and catalytic functionalities. The rate of hydrolysis of diphenyl carbonate (1) in the presence of the imprinted polymer IP-DVB-THF was found to be 120 times faster than the background uncatalyzed reaction. A Km of 32 mM and a kcat of 1.8 ${\times}$ 10-3min-1 were observed from Michaelis-Menten kinetics with the imprinted polymer IP-DVB-THF.

• 대한화학회지
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• 제63권1호
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• pp.24-28
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• 2019

In this work, we discuss where the failure of Kohn-Sham Density Functional Theory (DFT) occurs in weak interactions. We have adopted density-corrected density functional calculations and dispersion correction separately to find out whether the failure is due to density-driven error or functional error. The results of Benzene Ar complex, one of the most common examples of van der Waals interactions, show that DFT calculations of van der Waals interaction suffer from functional error, rather than density-driven error. In addition, errors in DFT calculations of the S22 dataset, which contains small to relatively large (30 atoms) complexes with non-covalent interactions, are governed by functional errors.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.749-752
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• 2013

Trehalose-tethered monomeric and dimeric berberines were synthesized in 50% and 30% from the reaction of berberrubine with 6-tosyl-${\alpha}$,${\alpha}^{\prime}$-trehalose and 6,6'-ditosyl-${\alpha}$,${\alpha}^{\prime}$-trehalose, respectively, and fully characterized by MS (HR and ESI) and NMR ($^1H$, $^{13}C$, COSY and HSQC). Spectrophotometric and spectrofluorimetric titrations indicated that compared with berberine, trehalose-tethered monomeric berberine had comparable DNA-binding affinity toward calf-thymus DNA, whereas trehalose-spaced dimeric berberine exhibited higher DNA-binding affinity. The potential application of these conjugates is also briefly discussed.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.709-710
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• 2000

유전자센서 기술은 biomedical analysis를 위해 일반적으로 고체 상에 고정화된 DNA 분자를 이용한다. 이 센서의 검출능력은 주로 capture probe의 서열뿐만 아니라 oligonucleotide의 고체 상에 고정화 방법에 달려있다. 본 연구에서는 glass 표면에 DNA 분자를 고정화시키는 두 가지 다른 방법을 비교하였고 유전자센서의 구성에 대해 검토하였다.

• Journal of Photoscience
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• 제11권1호
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• pp.29-33
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• 2004

The mechanism of interaction of cyanocobalamin (CB) with bovine serum albumin (BSA) has been investigated by spectrofluorometric and circular dichroism methods. Association constant for the CB-BSA system showed that the interaction is non-covalent in nature. Binding studies in the presence of an hydrophobic probe, 8-anilino-l-naphthalene sulphonic acid, sodium salt (ANS) showed that there is hydrophobic interaction between CB and ANS and they do not share common sites in BSA. Stern-Volmer analysis of fluorescence quenching data showed that the fraction of fluorophore (protein) accessible to the quencher (CB) was close to unity indicating thereby that both tryptophan residues of BSA are involved in drug-protein interaction. The rate constant for quenching, greater than $10^{10}$ $M^{-1}$ $s^{-1}$, indicated that the drug binding site is in close proximity to tryptophan residue of BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CB to BSA involves hydrophobic bonds predominantly. Significant increase in concentration of free drug was observed for CB in presence of paracetamol. Circular dichroism studies revealed the change in helicity of BSA due to binding of CB to BSA.