• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.247-254
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• 2015

In this presentation, I describe the expression and purification of the recombinant liver X receptor β-ligand binding domain proteins in E. coli using a commercially available double cistronic vector, pACYCDuet-1, to express the receptor heterodimer in a single cell as the soluble form. I describe here the expression and characterization of a biologically active heterodimer composed of the liver X receptor β-ligand binding domain and retinoid X receptor α-ligand binding domain. Although many of these proteins were previously seen to be produced in E. coli as insoluble aggregates or "inclusion bodies", I show here that as a form of heterodimer they can be made in soluble forms that are biologically active. This suggests that co-expression of the liver X receptor β-ligand binding domain with its binding partner improves the solubility of the complex and probably assists in their correct folding, thereby functioning as a type of molecular chaperone.

• Journal of the Korean Magnetic Resonance Society
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• v.2 no.1
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• pp.33-40
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• 1998

The cross peak intensities versus mixing times of 2D NOESY spectrum for a corepressor L-trp were simulated for the case of a ligand exchanging between free (AX) and bound (A'X') forms in protein/DNA complex. The direct NOE (I(AX)) of the free ligand exhibited a small positive intensity indicative of the strong dominant influence of the bound ligand. The exchange-mediated NOE peak (I(AX')) was very sensitive to corepressor exchange. However, both diagonal (I(A'A')) and direct NOE (I(A'X')) intensities of the bound ligand were not affected much at initial stage. Both peaks were severely influenced by exchange at mixing times of greater than 100 ms. In conclusion, since the NOE intensity is a function of exchange rate, the exchange effect should be considered to properly extract accurate distance information for bound ligand in the presence of conformational exchange.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.84-87
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• 2006

Batch binding experiments were performed to assess the recovery performance of glyceraldehyde 3-phosphate dehydrogenase (G3PDH) bound to the unshielded and polymer (polyvinyl pyrrolidone. PVP)-shielded dye-ligand (Cibacron Blue 3GA) adsorbent. The adoption of a polymer-shielded, dye-ligand technique facilitated the elution efficiency of bound G3PDH. It was demonstrated that the recovery of G3PDH using polymer-shielded dye-ligand adsorption yielded higher elution efficiency, at 60.5% and a specific activity of 42.3 IU/mg, after a low ionic strength elution (0.15 M NaCl). The unshielded dye-ligand yielded lower elution efficiency. at 6.5% and a specific activity of 10.2 IU/mg.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.973-976
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• 2011

The addition of organic ligand (${\beta}$-diketone or heterocyclic compound) to the europium (III)-containing ionic liquid resulted in bright luminescent soft materials with the molar ratio of europium/ionic liquid (IL)/ligand being 1:3:1 that exhibit bright red light under UV lamp. The luminescent properties such as emission features and lifetime of $^5D_0$ $Eu^{3+}$ excited level are dependent on the organic ligands. The materials were characterized by FT-IR and luminescence spectroscopy. The data shows that at least parts of the ILs (carboxylic acid) are replaced with ${\beta}$-diketone ligand rather than the formation of europium complex with the molar ratio of $Eu^{3+}$:IL: ligand being 1:3:1, while no ILs could be replaced by the heterocyclic ligand such as Bpy and Phen.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.976-981
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• 1997

The magnetic susceptibilities of molybdenum ions with 4d1 electronic configuration in the octahedral crystal field were calculated on the basis of ligand field theory. The experimental magnetic susceptibilities for molybdenum ions, which are stabilized at the octahedral site in the perovskite lattice of Ba2ScMoⅤO6 and Sr2YMoⅤO6, were compared with the theoretical ones. We have tried to fit their temperature dependence of magnetic susceptibility with ligand field parameters, spin-orbit coupling constant ζSO, and orbital reduction parameter κ according to intermediate field coupling and strong field theory. Strong field coupling theory could not explain experimental curves without unrealistically large axial ligand field, since it ignores the mixing up between different state via spin-orbit interaction and ligand field. On the other hand, the intermediate field coupling theory could successfully reproduce experimental data in octahedral and trigonal ligand field. The fitting result demonstrates not only the fact that spin-orbit interaction is primarily responsible for the variation of magnetic behavior but also the fact that effective orbital overlap, enhanced by cubic crystal structure, reduces significantly orbital angular momentum as indicated by κ parameter.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.1
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• pp.56-65
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• 2021

TSPO, an 18-kDa translocator protein, is a peripheral-type benzodiazepine receptor that has been associated to a variety of biological activities such as apoptosis, steroidogenesis, and cell proliferation. Because TSPO overexpression has been found in various forms of cancer, it has recently become one of the most appealing biological targets for cancer therapies and detection. In order to create new optical imaging agents for improved diagnostics, we synthesized a novel dimeric fluorescent TSPO ligand based on PRB28 structure and SCy5.5. Following the preparation of the novel TSPO ligand, in vivo and ex vivo imaging tests were performed to examine the tumor uptake characteristics of the fluorescent TSPO ligand in a glioma animal model, and it was found that novel TSPO ligand was accumulated in glioma. These results suggested that novel dimeric fluorescent TSPO ligand will be applied to detect glioma.

• Journal of Photoscience
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• v.11 no.1
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• pp.19-23
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• 2004

The sharp-line absorption spectrum of microcrystalline samples of cis-[Cr(cycb)$Cl_2$]Cl (cycb=rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been measured between 13000 and $16000 cm^{-1}$ at temperatures down to 5K. The 77K emission and excitation spectra, and 298 K infrared and visible absorption spectra have also been measured. The nine electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex. The zero-phonon line in the sharp-line absorption spectrum splits into two components by $240 cm^{-1}$ , and the $large ^2$$_E{g}$ splitting can be reproduced by the modem ligand field theory. It is confirmed that nitrogen atoms of the macrocyclic cycb ligand have a strong $\sigma$-donor character, but chloride ligand has weak $\sigma$- nd $\pi$-donor properties toward chromium(III) ion.n.

• Journal of environmental and Sanitary engineering
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• v.21 no.4 s.62
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• pp.49-60
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• 2006

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 - divinylbenzene(DVB) with 1%, 2%, 4% and 8%-crosslinking and 1-aza-18-crown-6 macrocyclic ligand by copolymerization method. Content of chlorine in styrene-DVB copolymer was decreased as crosslink increased and it is because as crosslink increased 1%, 2%, 4% and 8% DVB content increased and crosslink density increased and cavity was reduced. Functional group of resin almost disappeared as C-C1 peak around $700cm^{-1}$ was substituted with 1-aza-18-C-6 macrocyclic ligand and new peak of C-N around $1020cm^{-1}$ appeared, so it was confirmed that styrene-DVB copolymer and ligand were compounded. As crosslink increased in the analysis of element contents, it resulted in the reduction of nitrogen content and it is because as crosslink increased, it led to the reduction of chlorine content in the process of substitution reaction and it affected macrocyclic ligand substituted. Thermo analysis curve of functional synthetic resin decomposed three part of 1-aza-18-C-6, styrene, and DVB. Form of functional synthetic resin showed distortion of its particles as macrocyclic ligand was introduced to styrene-DVB copolymer and hydrogen of ligand caused substitution with chlorine element of styrene molecule.

• Journal of the Korean Chemical Society
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• v.11 no.2
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• pp.56-59
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• 1967

Mixtures of amines can be separated by elution chromatography on a chelating resin, Dowex A-1 loaded with nickel ions based on ligand exchange. Aqueous ammonia is used as the eluent. The method has proved particulary effective for separating aromatic amines.

• Bulletin of the Korean Chemical Society
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• v.19 no.5
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• pp.575-579
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• 1998

The 77 K luminescence and excitation spectra, and 298 K infrared and absorption spectra of $cis-{\Alpha}-[Cr(trien)Cl_2]Cl{\cdot}H_2O$ (trien=triethylenetetramine) have been measured. Ligand field electronic transitions due to spin-allowed and spin-forbidden are assigned. The zero-phonon line in the excitation spectrum splits into two components by $198\; cm^{-1}$, and the large $^2E_g$ splitting can be reproduced by the modern ligand field theory. It is confirmed that nitrogen atoms of the trien ligand have a strong σ-donor character, but chloride ligand has weak σ- and π -donor properties toward chromium(III) ion.