• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.671-676
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• 1998

In the present study, we first examined whether the changes in the DNA binding activities of the transcription factors, cAMP response element binding protein (CREB) and activator protein-1 (AP-1) mediate the long-term effects of morphine in differentiated SH-SY5Y human neuroblastoma cells. The increases in CREB and AP-1 DNA binding activities were time-dependent up to 6 days of morphine treatment (1, 4, and 6 days). However, the significant reduction in the DNA binding activities of CREB and AP-1 was observed after 10 days of chronic morphine $(10\;{\mu}M)$ administration. Secondly, we examined whether the changes of CREB and AP-1 DNA binding activities could be modulated by dopamine and haloperidol. Dopamine cotreatment moderately increased the levels of the CREB and AP-1 DNA binding activities induced by 10 days of chronic morphine treatment, and haloperidol cotreatment also resulted in a moderate increase of the CREB and AP-1 DNA binding activities. However, dopamine or haloperidol only treatment showed a significant increase or decrease of the CREB and AP-1 DNA binding activities, respectively. In the case of acute morphine treatment, the CREB and AP-1 DNA binding activities were shown to decrease in a time-dependent manner (30, 60, 90, and 120 min). Taken these together, in differentiated SH-SY5Y cells, morphine tolerance seems to involve simultaneous changes of the CREB and AP-1 DNA binding activities. Our data also suggest the possible involvement of haloperidol in prevention or reversal of morphine tolerance at the transcriptional level.

• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.163-171
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• 1989

To investigate the protein binding characteristics of cephalothin, the effects of ionic strength, pH and temperature on the binding of cephalothin to bovine serum albumin (BSA) were studied by UV difference spectrophotometric method. With increasing ionic strength at constant PH and temperature, association constant decreased, but the number of binding sites sites was about 2 constantly. It may be deduced that the binding process is not only due to electrostatic forces. And the increased association constant at high ionic strength is explained by conformational changes of BSA from complex to subunits. The pH effect on the affinity of interaction indicated that the binding affinity of drug is higher in the neutral region than in the alkaline region. And, at high pH value, the number of binding sites decreased from 2 to 1 because of the conformational changes of BSA in alkaline region. The decrease in binding affinity of BSA to drug with increasing temperature was characteristic of an exothermic reaction. And the negative sign of ${\Delta}G^{\circ}$ meant that the binding process occurs spontaneously under the experimental conditions. In cephalothin-BSA complex formation, since the net enthalpy change value and entropy change value are positive, it is assumed that hydrophobic bindings are predominant in this binding process.

• Molecules and Cells
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• v.40 no.5
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• pp.355-362
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• 2017

The ${\beta}2$ integrins are cell surface transmembrane proteins regulating leukocyte functions, such as adhesion and migration. Two members of ${\beta}2$ integrin, ${\alpha}M{\beta}2$ and ${\alpha}X{\beta}2$, share the leukocyte distribution profile and integrin ${\alpha}X{\beta}2$ is involved in antigen presentation in dendritic cells and transendothelial migration of monocytes and macrophages to atherosclerotic lesions. ${\underline{R}}eceptor$ for ${\underline{a}}dvanced$ ${\underline{g}}lycation$ ${\underline{e}}nd$ ${\underline{p}}roducts$ (RAGE), a member of cell adhesion molecules, plays an important role in chronic inflammation and atherosclerosis. Although RAGE and ${\alpha}X{\beta}2$ play an important role in inflammatory response and the pathogenesis of atherosclerosis, the nature of their interaction and structure involved in the binding remain poorly defined. In this study, using I-domain as a ligand binding motif of ${\alpha}X{\beta}2$, we characterize the binding nature and the interacting moieties of ${\alpha}X$ I-domain and RAGE. Their binding requires divalent cations ($Mg^{2+}$ and $Mn^{2+}$) and shows an affinity on the sub-micro molar level: the dissociation constant of ${\alpha}X$ I-domains binding to RAGE being $0.49{\mu}M$. Furthermore, the ${\alpha}X$ I-domains recognize the V-domain, but not the C1 and C2-domains of RAGE. The acidic amino acid substitutions on the ligand binding site of ${\alpha}X$ I-domain significantly reduce the I-domain binding activity to soluble RAGE and the alanine substitutions of basic amino acids on the flat surface of the V-domain prevent the V-domain binding to ${\alpha}X$ I-domain. In conclusion, the main mechanism of ${\alpha}X$ I-domain binding to RAGE is a charge interaction, in which the acidic moieties of ${\alpha}X$ I-domains, including E244, and D249, recognize the basic residues on the RAGE V-domain encompassing K39, K43, K44, R104, and K107.

• Molecules and Cells
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• v.44 no.11
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• pp.805-829
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• 2021

CCCTC-binding factor (CTCF) critically contributes to 3D chromatin organization by determining topologically associated domain (TAD) borders. Although CTCF primarily binds at TAD borders, there also exist putative CTCF-binding sites within TADs, which are spread throughout the genome by retrotransposition. However, the detailed mechanism responsible for masking the putative CTCF-binding sites remains largely elusive. Here, we show that the ATP-dependent chromatin remodeler, chromodomain helicase DNA-binding 4 (CHD4), regulates chromatin accessibility to conceal aberrant CTCF-binding sites embedded in H3K9me3-enriched heterochromatic B2 short interspersed nuclear elements (SINEs) in mouse embryonic stem cells (mESCs). Upon CHD4 depletion, these aberrant CTCF-binding sites become accessible and aberrant CTCF recruitment occurs within TADs, resulting in disorganization of local TADs. RNA-binding intrinsically disordered domains (IDRs) of CHD4 are required to prevent this aberrant CTCF binding, and CHD4 is critical for the repression of B2 SINE transcripts. These results collectively reveal that a CHD4-mediated mechanism ensures appropriate CTCF binding and associated TAD organization in mESCs.

• Archives of Pharmacal Research
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• v.19 no.4
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• pp.269-274
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• 1996

The binding interactions between human serum albumin (HSA) and the edible food dyes amaranth, tartrazine and sunset yellow have been studied. Intrinsic association constants and the free energy changes associated with dye-protein binding at physiological pH for amaranth and tartrazine, and at two different pH values for sunset yellow have been calculated from ultrafiltration data. The temperature dependence $(20-40^{\circ}C)$ of the intrinsic association constants at pH 7.4 for amaranth-HSA and tartrazine-HSA mixtures have been measured, from which a plot of the van't Hoff isochore exhibits a marked change in slope around $30^{\circ}C$ indicating a possible change in protein conformation. The number of dye binding sites on HSA is reported for all the above conditions. HSA-ligand binding enthalpies have been used in conjunction with the N-B transitional binding enthalpy for HSA, to calculate the enthalpy for the N-B transition when ligands are bound with the protein.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.414-419
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• 1994

This study was trying to find what physical changes occurred to albumin when it reacted with estrogen and other ligands. Each concentration of human serum albumin with 100$\mu$l estradiol reacted at the highest binding capacity of 280nm. In addition, 1 hr of reaction time showed the highest binding rate. Conformational changes in human serum albumin with dietylstillbesterol and N-ethyl-maleimide produced strong binding capacities. The changes were immediate and they did not increase or decrease over time. Effects of human serum albumin with estriol induced no interaction each other. The binding capacity of human serum albumin with vitamin D$_2$was lower than estradiol. and the highest binding rate showed 1 hr of reaction time. Vitamin D$_2$ was very similar to the binding capacity of estradiol.

• YAKHAK HOEJI
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• v.32 no.3
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• pp.182-186
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• 1988

Binding of four cephalosporins(cefaclor, cefpiramide, ceftazidime, ceforanide) to bovine serum albumin was studied. Difference spectrophotometry was employed to evaluate the nature and the degree of association of cephalosporin-albumin complex. 2-(4'-hydroxybenzen azo) benzoic acid was used as the uv spectrophotometric probe for measuring the binding of cephalosporins to bovine serum albumin. Competitive bindings between cephalosporins and probe were observed. For the binding of cephalosporins to bovine serum albumin, three binding sites were identified. The binding constants of cefaclor, ceforanide, ceftazidime and cefpiramide were $12.57\;{\times}\;10^{-2}M^{-1}$, $6.49\;{\times}\;10^{-2}M^{-1}$, $4.70\;{\times}\;10^{-2}M^{-1}$ and $6.20\;{\times}\;10^{-2}M^{-1}$ respectively.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.35-40
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• 2005

Interaction of twelve erythromycin A analogues with 50S ribosomal subunit were studied employing AutoDock 3.0.5. Results showed that all active macrolides bound at the same binding site with erythromycin A in contrast to the inactive analogues which bound at location slightly different than erythromycin A. The binding site showed consistency with the X-ray data from the perspectives of hydrogen bonding and hydrophobic interactions formed by erythromycins, roxithromycin, azithromycin, cethromycin and telithromycin with the ribosome. The inactive derivatives of erythromycin A anhydride showed higher binding free energy, while 5-desosaminyl erythronolides A and B even though having quiet similar values of binding free energy with the active analogues, docked at binding sites which are quiet different than the active analogues. These results suggest the molecular docking technique can be used in predicting the binding of erythromycin A analogues to their ribosomal target.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.109-117
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• 2006

The Rev binding to Rev Responsive Element (RRE) of HIV-1 mRNA plays an important role in the HIV-I viral replication cycle. The disruption of the Rev-RRE interaction has been studied extensively in order to develop a potential antiviral drug. In order to provide the basis for a more promising approach to develop a Rev-RRE binding inhibitor against HIV-I infection, it is necessary to understand the binding modes of the aminoglycoside antibiotics to RRE. In the present study, the binding mode of a modified antibiotic, a neamine conjugated with pyrene and arginine (NCPA), to RRE has been studied by the methods of $T_m$ measurement and spectroscopic analysis of RRE with or without antibiotics. The results confirmed that NCPA competes with Rev in binding to RRE.

• 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.