• BMB Reports
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• v.29 no.6
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• pp.525-529
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• 1996

Ligand binding properties of muscarinic acetylcholine receptors (mAChRs) in the nematode Caenorhabditis elegans (C. elegans) were characterized by using filtration binding assays. Scatchard analysis using $[^{3}H]N-methylscopolamine$ ($[^{3}H]NMS$) showed that the dissociation constant ($K_d$) and the maximum binding value ($B_{max}$) were $3.3{\pm}0.8{\times}10^{10}$ M and $9.0{\pm}1.1$ fmol/mg protein, respectively. Binding competition experiments indicated that the affinities of C. elegans mAChRs to atropine, scopolamine, and oxotremorine were similar to those of mammalian mAChRs. Pirenzepine binding experiments revealed that the binding pattern of mAChRs in C. elegans closely resembled that of mAChRs in rat brain, suggesting that the receptors consist primarily of Ml subtype. The affinity of mAChRs for oxotrernorine was significantly affected by guanylylimidodiphosphate (Gpp(NH)p), a non hydrolyzable GTP analog, suggesting that mAChRs in C. elegans might be coupled to G proteins. The data presented here indicate the possibility that C. elegans provides a living animal model to study the action mode of the muscarinic cholinergic system.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.537-540
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• 2006

Over the past few decades, a considerable number of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in modeling of ionic flows. However, the majority of these researches have not dealt with the chloride binding isotherm based on the mechanism, although chloride binding capacity can significantly impact on the total service life of concrete under marine environment. The purpose of this study is to develop the model of chloride binding isotherm based on the individual mechanism. It is well known that chlorides ions in concrete can be present; free chlorides dissolved in the pore solution, chemical bound chlorides reacted with the hydration compounds of cement, and physical bound attracted to the surface of C-S-H grains. First, sub-model for water soluble chloride content is suggested as a function of pore solution and degree of saturation. Second, chemical model is suggested separately to estimate the response of binding capacity due to C-S-H and Friedel's salt. Finally, physical bound chloride content is estimated to consider a surface area of C-S-H nano-grains and the distance limited by the Van der Waals force. The new model of chloride binding isotherm suggested in this study is based on their intrinsic binding mechanisms and hydration reaction of concrete. Accordingly, it is possible to characterize chloride binding isotherm at the arbitrary stage of hydration time and arbitrary location from the surface of concrete. Comparative study with experimental data of published literature is accomplished to validity this model.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2753-2757
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• 2014

INtegrase Interactor 1 protein (INI1/hSNF5) or BRG1-associated factor 47 (BAF47) is a SWI/SNF-related matrix associated actin dependent regulator of chromatin subfamily B member. DNA binding domain of INI1/hSNF5 is cloned into E.coli expression vectors, pET32a and purified as a monomer using size exclusion chromatography. NMR data show that $INI1^{DBD}$ has folded state with high population of ${\alpha}$-helices. By fluorescence-quenching experiments, binding affinities between $INI1^{DBD}$ and two double stranded DNA fragments were determined as $29.9{\pm}2.6{\mu}M$ (GAL4_1) and $258.7{\pm}5.8$ (GAL4_2) ${\mu}M$, respectively. Our data revealed that DNA binding domain of INI1/hSNF5 binds to transcriptional DNA sequences, and it could play an important role as a transcriptional regulator.

• 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.

• BMB Reports
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• v.45 no.10
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• pp.577-582
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• 2012

single-minded (sim) is a master regulatory gene that directs differentiation in the central nervous system during Drosophila embryogenesis. Recent identification of the mesectoderm enhancer (MSE) of sim has led to the hypothesis that two Snail (Sna)-binding sites in the MSE may repress sim expression in the presumptive mesoderm. We provide evidence here that three Sna-binding sites proximal to the sim promoter, but not those of the MSE, are responsible for the mesodermal repression of sim in vivo. Using transgenic embryos injected with lacZ transgenes, we showed that sim repression in the mesoderm requires the three promoter-proximal Sna-binding sites. These results suggest that Sna represses the mesectodermal expression of sim by directly repressing the nearby promoter, and not by quenching adjacent transcriptional activators in the MSE. These data also showed how the MSE, lacking the three proximal Sna-binding sites, reproduced the endogenous pattern of sim expression in transgenic embryos.

• Journal of Photoscience
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• v.11 no.32
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• pp.65-69
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• 2004

The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.16-20
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• 2014

KR-31064 was developed for the strong angiotensin II receptor antagonist among the one of pyridyl imidazol series compounds. To investigate the receptor-ligand binding characteristics of this nonpeptide antagonist, binding experiments were deployed in various conditions and ex vivo contractile responses were tested toward the standard compound, losartan. Receptor binding experiments with radiolabeled angiotensin II, the $IC_{50}$ value for KR-31064 resulted 0.67 nM without any activities toward type 2 angiotensin II receptor. The comparative potency against losartan was more than 18 fold and the specific activity in type 1 angiotensin II receptor was more than 10,000 fold comparing to the type 2 receptor. Scatchard analysis of saturation binding data showed KR-31064 acted on the receptor in a competitive mode. KR-31064 inhibited the contractile response derived by angiotensin II ($pK_B$: 9.86) similar to that of losartan with decreased maximum signals. As a potent and specific type 1 angiotensin II receptor antagonist, KR-31064 may have possibilities for the development of diagnostic ligands that can be used as tools for various biochemical research experiments and non-invasive diagnostics.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.49-52
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• 2011

Competitive binding of $C_{60}$ and $C_{70}$ to meso-substituted porphyrins was studied by mass spectrometry (MS). Electrospray ionization MS was employed to acquire the mass spectra of 1 : 1 porphyrin-fullerene complexes formed in a mixture of mesosubstituted porphyrin and fullerite to determine the ratio of complexes between $C_{60}$ and $C_{70}$. Matrix-free laser desorption ionization MS was used to obtain the mass spectra of fullerite to measure the mole fraction of $C_{60}$ and $C_{70}$. The binding constant ratio ($K_{70}$/$K_{60}$) was determined from the mass spectral data. The difference in standard Gibbs free energy change, ${\Delta}({\Delta}G^o)_{70-60}$, for the competitive binding of $C_{60}$ and $C_{70}$ was calculated from $K_{70}$/$K_{60}$. Of the five porphyrins, tetraphenyl, tetra(4-pyridyl), tetra(4-carboxyphenyl), tetra(3,5-di-tert-butylphenyl), and tetra(pentafluorophenyl) porphyrins, the first three non-bulky porphyrins yield negative values of ${\Delta}({\Delta}G^o)_{70-60}$, whereas the other two bulky porphyrins result in positive values of ${\Delta}({\Delta}G^o)_{70-60}$. This result indicates that $C_{70}$ binding to porphyrin is thermodynamically favored over $C_{60}$ binding in non-bulky porphyrins, but disfavored in bulky ones. It also suggests that the binding mode of $C_{70}$is different between non-bulky and bulky porphyrins, which is in line with previous experimental findings of the "side-on" binding to non-bulky porphyrins and the $C_{60}$-like "end-on" binding to bulky porphyrins.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.530-530
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• 2000

The host defense system or immune system of all modern animals has their roots in very ancient organisms. After analyzing literature data concerning properties of invertebrates and vertebrates lectins we suggest that mechanism of mannans recognition may exist in marine invertebrates, as a universal mechanism for homeostasis maintenance and host defense, and mannan-binding lectins family of vertebrates has ancient precursor, as was shown for another S-type lectins family. We carried out the screening of mannan-binding type lectin among different species of echinoderms inhabiting in Piter the Grate Bay, the sea of Japan. As a result, the C-type lectins (SJL-32) specific for high mannose glycans was isolated from the coelomic plasma of the sea cucumbers Stichopus japonicus by ion-exchange chromatography on a DEAE-Toyopearl 650M, affinity chromatography on a mannan-Sepharose 6B and gel filtration on a Sephacryl S-200. SJL-32 is homodimer with molecular mass about 32 kDa on SDS-PAGE under non-reducing conditions. Protein part of the lectin has high conteins Asn, Glu, Ser. Hemagglutination of trypsin-treated O blood group human erythrocytes by SJL-32 was competitively inhibited by high-branched -D-mannan composed of -1,2 and -1,6 linked D-mannopyranose residues. In contrast, a variety of mono-, oligo-, and polysaccharides composed of residues of galactose and fucose showed absence or little inhibitory activities. The lectin activity strong depends on Ca2+ concentration, temperature and pH. Monospecific polyclonal antibodies were obtained to the lectin. As was shown by ELISA assay, antibodies to SJL-32 cross-reacted with human serum mannan-binding lectin. This data allows making conclusion about common antigenic determinants and structural homology of both lectins. In our opinion, SJL-32 belongs to evolutionary high conservative mannan-binding lectins (MBLs) family and takes part in the host defense against pathogenic microorganisms.

• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.255-260
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• 1994

There are some reports about the influences of free fatty acids on the albumin binding of drugs. But they were concerned to the limited free fatty acids, mostly of azapropazone-warfarin bidning site bound drugs and determination of dissociation and association constants by stopped flow technique. These data were not enough to make conculsions for the general tendency of free fatty acid to albumin binding. Therefore the influence of various saturated fatty acids of $C_{10{\sim}20}$, oleic acid and linoleic acid as unsaturated fatty acids to albumin binding of warfarin and dansylsarcosine were studied by equilibrium dialysis. The concentration of free drug was determined by spectrophotometer according to the molar ratios of 0, 0.5, 1, 2 and 4 between free fatty acid and albumin. There were significant increasing in the free durg concentration of warfarin and dansylsarcosine when the molar ratio for capric acid, lauric acid and palmitic acid was 4. The free warfarin concentration was increased significantly at a molar ratio of 4 between oleic acid and albumin. Therefore the albumin binding of durgs can be variated significantly by increased free fatty acid of diabetics and cause to the pharmacokinetic variation between healthy and diabetics.