• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.125-137
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• 2013

2012년 G 단백질 연결 수용체(G-Protein Coupled Receptors ; GPCR) 연구가 노벨 화학상을 받았다. 상당히 많은 병과 관련되어 있어 잠재력이 크고, 많은 연구가 진행 중이다. 현재 리간드와 단백질간의 정전기적 포텐셜 연구를 통한 예측 연구가 진행되고 있지만, GPCR과 리간드 간의 연구에서 아직 리간드의 전하를 통한 단백질과 리간드간의 상호작용 예측 연구가 되어 있지 않다. 그렇기 때문에 이번 연구에서는 8가지 방법으로 전하(charge)를 띠게 하여서 단백질과 리간드의 상호작용을 계산을 통하여 예측하여 보았다.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1079-1085
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• 1999

An investigation was made of the effect of various transition metal catalysts, ligands, and a promoter on the synthesis of N,N'-diphenylurea(DPU) from nitrobenzene, aniline, and carbon monoxide. Homogeneous Pd and Ni catalysts were found to be highly efficient, giving almost quantitative isolated DPU yields at 100% nitrobenzene conversion. Bidentate ligand, 1,3-bis(diphenylphosphino)proane(dppp) showed much improved activity and significantly different reactivity relative to the usual monodentate $PPh_3$ ligand in the presence of Ni and Pd catalysts. These results were inferred to the effect of the cis coordination of bidentate dppp ligand on the metal. The use of a promoter $Et_4NCl$ was indispensable in the case of $PPh_3$, yet inhibited the reaction if used with dppp. It was possible to reuse the Pd-dppp catalyst system, although the catalytic activity was reduced slowly.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.148-154
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• 1982

The effects of the various ligands on the oscillator strengths of the hypersensitive transitions of Nd(III) and Ho(III) have been studied in aqueous solution. The ligands used in the study are furoate, anthranilate, and squarate. The covalent character of the metal-ligand bond in the complex is discussed on the basis of the correlation diagram between pKa of the ligands and the oscillator strengths of the complexes previously reported.

• Journal of Life Science
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• v.14 no.1
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• pp.14-16
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• 2004

Various ligands function as regulators in the allosteric control of tryptophan synthase. Effects of the monovalent cations and glycerophosphate on the mutant tryptophan synthases were examined in the presence of L-serine. The results showed that these compounds might play roles in the allosteric control of the proteins.

• Journal of the Korean Chemical Society
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• v.24 no.1
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• pp.15-19
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• 1980

CNDO/2, EHT molecular orbital methods are used to investigate the electronic structure and reactivity of glycinato, glycine ester ligands. The results show that bidentate glycinato has a more stable structure, Gly-I with a $105.9^{\circ}$dihedral angle between ${\Delta}O_4C_3C_2$ and ${\Delta}C_3C_2N_1$ than Gly-Ⅱ. The electron inductive effects in the alkyl group substituted glycine ester ligands can also be derived from the calculation. According to the electron density, qN of ligands on the basis of CNDO/2 MO calculations, it is concluded that the stabilities are in the order of glycinato > Gly-Et-ester > Gly-i-Pr-ester > Gly-Me-ester.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.733-737
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• 2006

In this paper, we report the coordination state and structure of $Zn(cyclam)Cl_{2})$ complex that was studied by the Raman spectrum and conductivity method. The complex of zinc(II) ion with 1,4,8,11-tetraazacyclotetradecane(cyclam) ligand is formed in aqueous solution. According to the Raman spectrum of $Zn(cyclam)Cl_{2})$ complex, $H_{2}O$ molecule and $Cl^{-}$ ion compete for the trans coordination site of zinc(II) ion. We also have investigated the competition effect of $H_{2}O$ molecule and $Cl^{-}$ ion by the conductivity method. On addition of 1,4,8,11-tetraazacyclotetradecane(cyclam) ligand to the aqueous $ZnCl_{2}$ solution, 2: 1 electrolyte is changed to 1:1 electrolyte. We suggest the possibility of elimination of heavy metal because of the affinity effect of macrocyclic polyamine(1,4,8.11-tetraazacyclotetradecane) for the heavy metal,.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.212-217
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• 1992

The thermodynamic parameters for the formation of gadolinium benzoate have been determined in the ionic medium of 0.1 M $NaClO_4$ at $25^{\circ}C$ in aqueous solution. The thermodynamic results indicate that the complex is stabilized by the excess entropy effect caused by the dehydration of reacting ions. The especially high stability of Gd(III)-benzoate compared to the monodentate ligand complexes might be ascribed to the conjugation effect of the benzene ring in the benzoate ligand. IR spectra show that benzoate anion acts as a bidentate ligand toward $Gd^{3+}$ to form a chelate ring in solid state. Magnetic susceptibility data of the compound were also obtained and well described by Curie-Weiss law in the temperature range 80${\sim}$300K.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.585-590
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• 2003

Cobalt oxygen carrier complex N,N'-ethylenebis(3-methoxysalycylideneiminato)cobalt(II), Co(3MeOsalen) was prepared at $25{\circ}C$. UV and visible absorption spectra of the complex and hydrazobenzene were studied in non-aqueous solvent methanol in the range of wavelength 200-600 nm. The oxidation of hydrazobenzene by oxygen in non-aqueous solvent is catalysed by Co(3MeOsalen). In the presence of triphenylphosphine($PPh_3$), the rate decreases in methanol. This is presumably attributable to the coordination of $PPh_3$ to the Co(3MeOsalen), resulting in the catallytically inactive compound. The initial rates of the oxidation of hydrazobenzene with the ligand triphenylphosphine were measured by the theoretical values of the rates, Rate=$k_1+k_2K_1[P]/1+K_1[P]+K_1K_2[P]^2$. This fact would be a poorer σ-donor ligand than methanol.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.36-41
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• 1998

In this study, the extraction of Co(Ⅱ) and Cu(Ⅱ) into chloroform solution of dithizone, distribution ratios, extractabilities and extraction rate constants of the metal complexes were compared in each case with which thiocyanate ion was or not used as the auxiliary ligand. The use of the thiocyanate ion increased threefold the distribution ratio for Co(Ⅱ) complex in a basic solution and twofold for Cu(Ⅱ) complex in a wide pH range. And the extractability was also augmented from about 90 to 99 for Co(Ⅱ) and from 95 to 99 for Cu(Ⅱ) in a given period. The extraction rate constants were $k_1\;:\;1.2{\times}10^5$, $k_2\;:\;1.34{\times}10^{17}\; mol^{-1}dm^3s^{-1}$ in case of Co(Ⅱ) and$k_1\;:\;1.1{\times}10^8$, $k_2\;:\;2.83{\times}10^{10}\; mol^{-1}dm^3s^{-1}$ in case of Cu(Ⅱ) on the extraction of dithizonate complexes into chloroform solution.

• Journal of Life Science
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• v.23 no.10
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• pp.1216-1222
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• 2013

NK cells are lymphoid immune cells that participate in innate immunity to protect against foreign pathogens and transforming cells. It is known that the activity of NK cells is regulated by a balance between activating and inhibitory signals rather than specific antigens. One important activating signal is mediated by the NKG2D receptor, which recognizes NKG2D ligands on cancer cells. Therefore, tumor cells that express sufficient amounts of NKG2D ligands could be eliminated by NKD2D+ cells, including NK cells. Oncogenes drive tumor cells to apoptosis resistant and uncontrolled proliferation by altered expression of many critical genes. Therefore, the expression of NKG2D ligands may be affected by oncogenes. This study focused on increasing the susceptibility of cancer cells to NK cells by regulating the expression of NKG2D ligands influenced by three oncogenes: k-ras, wnt, and c-myc. We demonstrated that inhibition of k-ras and c-myc increased the expression of NKG2D ligands and enhanced the susceptibility of cancer cells to NK cells. On the contrary, inhibition of the wnt pathway decreased MICA and ULBP1 transcripts. Although the decreased transcription of NKG2D ligands by inhibition of the wnt pathway, surface proteins of NKG2D ligands were not changed, and the susceptibility of HCT-116 cells was unaffected. The results demonstrate that the transcription of NKG2D ligands are regulated deferentially by the k-ras, c-myc, and wnt pathways and that the cytotoxicity of NK cells solely depends on the amount of surface NKG2D ligands.