• Bulletin of the Korean Chemical Society
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• 제29권3호
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• pp.663-665
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• 2008

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제3권12호
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• pp.455-462
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• 2014

최근에는 모바일 기기 자체의 성능뿐만 아니라 무선 네트워크 등의 연관 기술들이 발달함에 따라 모바일 환경에서의 다양한 서비스에 대한 관심이 높아지고 있는 추세이다. 게다가 급증하는 통신 부하 문제가 새로운 이슈로 떠오르면서 단말 간 직접 통신(D2D)과 이에 기반한 단말간의 협력 서비스 방식에 대한 연구가 활발해지고 있다. 본 논문에서는 D2D 기반의 협력 서비스를 위한 스마트 에이전트 시스템을 설계하고 서비스 온톨로지 기반의 동적 서비스 바인딩 기법을 제안한다. 3가지 타입의 에이전트를 설계하여 협력 서비스를 위한 역할을 구분하고, 에이전트의 기능을 서비스 단위로 모델링하여 속성을 기술함으로써 지식 베이스를 구축한다. 제안한 지식 모델인 D2D 협력 서비스 온톨로지는 실시간의 상황이 지속적으로 변화하는 모바일 환경에서 가변적인 상황에 따라 필요한 서비스를 최적의 멤버 기기에게 동적으로 바인딩함으로써 효율적이고 자율적인 협력 서비스를 가능케 할 수 있는 핵심 기술이라 할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제5권3호
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• pp.108-112
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• 1984

Interactions between metal ions and chitosan in solution were studied by spectroscopic and viscometric measurements. $Cu^{++}$-chitosan complex exhibited an absorption band at 265 nm, whereas D-glucosamine complex showed one at 245 nm. The difference in ${\lambda}_{max}$ was attributed to the different amine to $Cu^{2+}$ ratios of the complexes, that is, 2 : 1 for chitosan and 1 : 1 for D-glucosamine. The molar absorptivities and binding constants of the complexes were evaluatatled. The binding of $Cu^{2+}$ to chitosan was cooperative near pH 5, and both intra- and intermolecular chelations depending on chitosan and $Cu^{2+}$concentrations were observed, The intermolecular chelation was stabilized by addition of salts. The cooperative intermolecular chelation of $Ni^{++}$ was also observed at pH 6.2. No significant binding of other divalent ions was observed. The reported high adsorption abilities of chitosan particles for these ions were attributed to the deposition of metal hydroxide aggregates in pores of chitosan particles rather than chelation to amine groups.

• Bulletin of the Korean Chemical Society
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• 제21권5호
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• pp.461-462
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• 2000

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.953-958
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• 2008

A novel anthraquinone diamino-bridged bis($\beta$ -cyclodextrin) 2 was synthesized. The inclusion complexation behaviors of the native $\beta$ -cyclodextrin 1 and the novel bis($\beta$ -cyclodextrin) 2 with guests, such as acridine red (AR), neutral red (NR), ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 2-(p-toluidinyl) naphthalenesulfonate (TNS) and rhodamine B (RhB) were investigation by fluorescence, circular dichroism and 2D NMR spectroscopy. The spectral titrations were performed in phosphate buffer (pH 7.20) at 25 ${^{\circ}C}$ to give the complex stability constants (Ks) and Gibbs free energy changes (−${\Delta}G^0$) for the stoichiometric 1:1 inclusion complexation of host 1 and 2 with guests. The results indicated that the novel bis($\beta$ -cyclodextrin) 2 greatly enhanced the original binding affinity of the native $\beta$ -cyclodextrin 1. Typically, bis($\beta$ -cyclodextrin) 2 showed the highest binding constant towards ANS up to 34.8 times higher than that of 1. The 2D NMR spectra of bis($\beta$ -cyclodextrin) 2 with RhB and TNS were performed to confirm the binding mode. The increased binding affinity and molecular selectivity of guests by bis($\beta$ -cyclodextrin) 2 were discussed from the viewpoint of the size/shape-fit concept and multipoint recognition mechanism.

• BMB Reports
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• 제29권1호
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• pp.1-10
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• 1996

The binding interaction of ethidium to a series of synthetic deoxyoligonucleotides containing a B-Z junction between left-handed Z-DNA and right-handed B-DNA, was studied. The series of deoxyoligonucleotides was designed so as to vary a dinucleotide step immediately adjacent to a B-Z junction region. Ethidium binds to the right-handed DNA forms and hybrid B-Z forms which contain a B-Z junction, in a highly cooperative manner. In a series of deoxyoligonucleotides, the binding affinity of ethidium with DNA forms which were initially hybrid B-Z forms shows over an order of magnitude higher than that with any other DNA forms, which were entirely in B-form DNA The cooperativity of binding isotherms were described by an allosteric binding model and by a neighbor exclusion model. The binding data were statistically compared for two models. The conformation of allosterically converted DNA forms under binding with ethidium is found to be different from that of the initial B-form DNA as examined by CD spectra. The ratio of the binding constant was interestingly correlated to the free energy of base unstacking and the conformational conversion of the dinucleotide. The more the base stacking of the dinucleotide is unstable, or the harder the conversion of B to A conformation, the higher the ratio of the binding constant of ethidium with the allosterically converted DNA forms and with the initial B-Z hybrid forms. DNA sequence around a B-Z junction region affects the binding affinity of ethidium. The results in this study demonstrate that ethidium could preferentially interact with unusual DNA structures.

• BMB Reports
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• 제35권2호
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• pp.143-154
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• 2002

The structural and functional aspects of ervatamin B were studied in solution. Ervatamin B belongs to the $\alpha+\beta$ class of proteins. The intrinsic fluorescence emission maximum of the enzyme was at 350 nm under neutral conditions, and at 355 nm under denaturing conditions. Between pH 1.0-2.5 the enzyme exists in a partially unfolded state with minimum or no tertiary structure, and no proteolytic activity. At still lower pH, the enzyme regains substantial secondary structure, which is predominantly $\beta$-sheet conformation and shows a strong binding to 8-anilino-1-napthalene-sulfonic acid (ANS). In the presence of salt, the enzyme attains a similar state directly from the native state. Under neutral conditions, the enzyme was stable in urea, while the guanidine hydrochloride (GuHCl) induced equilibrium unfolding was cooperative. The GuHCl induced unfolding transition curves at pH 3.0 and 4.0 were non-coincidental, indicating the presence of intermediates in the unfolding pathway. This was substantiated by strong ANS binding that was observed at low concentrations of GuHCl at both pH 3.0 and 4.0. The urea induced transition curves at pH 3.0 were, however, coincidental, but non-cooperative. This indicates that the different structural units of the enzyme unfold in steps through intermediates. This observation is further supported by two emission maxima in ANS binding assay during urea denaturation. Hence, denaturant induced equilibrium unfolding pathway of ervatamin B, which differs from the acid induced unfolding pathway, is not a simple two-state transition but involves intermediates which probably accumulate at different stages of protein folding and hence adds a new dimension to the unfolding pathway of plant proteases of the papain superfamily.

• 한국염색가공학회지
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• 제5권3호
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• pp.182-187
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• 1993

The binding isotherms of Methylene Blue with Poly(vinyl pyrrolidone) (PVP) were determined in a Mcllvaine buffer of pH 8.0 at 3$0^{\circ}C$ by a dynamic dialysis methods. The isotherms showed a partition binding which was increase linearly with the increase of free dye concentration in solution. The Scatchard plots for Poly(vinyl pyrrolidone)-Methylene Blue gave a constant value. The results were interpreted by the McGhee and von Hippel theory considering non-cooperative binding. The intrinsic binding constant k, for Poly(vinyl pyrrolidone)-Methylene Blue was 6.02$\ell$/base mol.

• 한국염색가공학회지
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• 제24권4호
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• pp.239-246
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• 2012

The binding isotherms of ionic dyes with Poly(vinylpyrrolidone) in aqueous solution were determined by the dynamic dialysis technique. The shape of the isotherms of cationic dye, C. I. Basic Red 18 with poly(vinlypyrrolidone) showed a partition type. It suggests that the binding involves a non-cooperative mode. Isotherms of an anion dye, a synthesized dye by coupling of diazotized m-trifluoromethylaniline with 2-naphthol-6-sulfonic acid, were sigmoid type and showed multimode interaction. The results were interpreted by the McGhee von Hippel theory. The thermodynamic parameters for the complex formation of the dyes-polymer were calculated from their temperature dependences of the intrinsic binding constant.

• BMB Reports
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• 제31권1호
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• pp.25-30
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• 1998

Kinetic studies of L-Alanine dehydrogenase from Bacillus subtilis-catalyzed reactions in the presence of $Zn^{2+}$ were carried out. The substrate (L-alanine) saturation curve is hyperbolic in the absence of the metal ion but it becomes sigmoidal when $Zn^{2+}$ is added to the reaction mixture indicating the positive cooperative binding of the substrate in the presence of zinc ion. The cooperativity of substrate binding depends on the xinc ion concentration: the Hill coefficients ($n_H$) varied from 1.0 to 1.95 when the zinc ion concentration varied from 0 to $60\;{\mu}m$. The inhibition of AlaDH by $Zn^{2+}$ is reversible and noncompetitive with respect to $NAD^+$ ($K_i\;=\;5.28{\times}10^{-5}\;M$). $Zn^{2+}$ itself binds to AlaDH with positive cooperativity and the cooperativity is independent of substrate concentration. The Hill coefficients of substrate biding in the presence of $Zn^{2+}$ are not affected by the enzyme concentration indicating that $Zn^{2+}$ binding does not change the polymerization-depolymerization equilibria of the enzyme. Among other metal ions, $Zn^{2+}$ appears to be a specific reversible inhibitor inducing conformational change through the intersubunit interaction. These results indicate that $Zn^{2+}$ is an allosteric competitive inhibitor and substrate being a non-cooperative per se, excludes the $Zn^{2+}$ from its binding site and thus exhibits positive cooperativity. The allosteric mechanism of AlaDh from Bacillus subtilis is consistent with both MWC and Koshland's allosteric model.