• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1995.04a
• /
• pp.86-86
• /
• 1995

The analysis of membrane receptors for hormones and neurotransmitters has progressed considerably by pharmacological and biochemical means and more recently by the use of specific anti-receptor antibodies. A 14-mer peptide (from Phe102 to Leu115 of ${\beta}$2-adrenergic receptor) was synthesized and this peptide was coupled to carrier protein Keyhole Limpet Hemocyanin(KLH) by glutaraldehyde method. A 0.5mg of KLH-coupled peptide was emulsified with equal volume of complete Freund's adjuvant and injected via popliteal lymph node to each of the three Newzealnd White rabbits. Booster injections were repeated at 4 weeks interval for three times with incomplete Freund's adjuvants. One week after the final injection, serum was prepared from ear artery. Nonspecific immunoglobulins were removed by passing the serum through KLH-Sepharose 6B affinity matrix and further by incubation with bovine lung aceton powder. The titer of the antibody for synthetic peptide which was determined by enzyme linked immunosorbent assay(ELISA) was about l/l,000. The antibody produced in this study revealed 67kDa protein band in the western blot of partially purified guinea pig lung ${\beta}$-adrenergic receptor preparation. The antibody inhibited ${\beta}$-adrenergic antaginist [3H] Dihydroalprenolol binding to soluble ${\beta}$-adrenergic receptor by 25% while control sera did not show any inhibitory effects, The result of this study suggests that the peptide sequence selected in this study may play some important roles in adrenergic receptor-ligand interaction.

• The Korean Journal of Nuclear Medicine
• /
• v.31 no.4
• /
• pp.440-451
• /
• 1997

This study was designed to prospect the $^{111}In$-labelled paclitaxel as tumor imaging agent. In order to provide a taxol molecule with a functional group which is able to chelate In-111, taxol-DTPA conjugate and 2'-hemisuccinyltaxol were synthesized by esterification of taxol at C-2'on C-13 carbon with DTPA anhydride and succinic anhydride, respectively. Synthesis yield of the taxol derivatives was 34% for taxol-DTPA and 80% for 2'-hemisuccinyltaxol. Cytotoxicity of the taxol derivatives were measured by MTT method toward cell lines HT29, B16, P388, and CT26. The cytotoxic activities of the taxol derivatives were maintained, although less active than taxol. Radiolabelling of the taxol derivatives were proceeded directly with $^{111}InCl_3$ or indirectly with $^{111}In$-citrate(ligand-exchange method). The ligand-exchange method was not suitable because some precipitates appeared during the reaction. On the contrary, by direct radiolabelling method, we were able to obtain taxol-DTPA-$^{111}In$ in 100% radiochemical yield. However, 2'-hemisuccinyltaxol was not labelled by both methods. Yield and radiochemical purity of the radiolabelled com-pound were determined by HPLC, paper chromatography and instant thin layer chromatography. Taxol-DTPA-$^{111}In$ was characterized to be hydrophilic by lipophilicity test, and nearly non-adhesive to HT29, B16, P388, and CT26 by cell binding affinity test. Binding affinity of the taxol-DTPA-$^{111}In$ complex to serum proteins was also examined by protein precipitation with 30% trichloroacetic acid. The results showed that 30% of the taxol-DTPA-$^{111}In$ complex binds with serum proteins.

• Natural Product Sciences
• /
• v.24 no.2
• /
• pp.88-92
• /
• 2018

The present study was undertaken to investigate the isolated compounds from the stem bark of Garcinia atroviridis as potential cholinesterase inhibitors and the ligand-enzyme interactions of selected bioactive compounds in silico. The in vitro cholinesterase results showed that quercetin (3) was the most active AChE inhibitor ($12.65{\pm}1.57{\mu}g/ml$) while garcinexanthone G (6) was the most active BChE inhibitor ($18.86{\pm}2.41{\mu}g/ml$). It is noteworthy to note that compound 6 was a selective inhibitor with the selectivity index of 11.82. Molecular insight from docking interaction further substantiate that orientation of compound 6 in the catalytic site which enhanced its binding affinity as compared to other xanthones. The nature of protein-ligand interactions of compound 6 is mainly hydrogen bonding, and the hydroxyl group of compound 6 at C-10 is vital in BChE inhibition activity. Therefore, compound 6 is a notable lead for further drug design and development of BChE selective inhibitor.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.180.2-180.2
• /
• 2003

Cathepsin K, a cysteine protease of the papain superfamily, is predominantly expressed in osteoclasts and has been postulated as a target for the treatment of osteoporosis. Crystallographic and structure-activity studies on a series of azepanone-based diamino and acyclic ketone derivative inhibitors of cathepsin K have led to the design and identification. X-ray structure of the cysteine protease cathepsin K (1NL6) co-crystalized with an inhibitor with 2.8${\AA}$ resolution was used to predict the protein-ligand interactions and to estimate the binding affinity from the docking score by FlexX module. (omitted)

• Korean Journal of Microbiology
• /
• v.54 no.4
• /
• pp.330-342
• /
• 2018

The Streptavidin and Biotin system has been studied most extensively as the high affinity non-covalent binding of Biotin to STR ($K_D=10^{-14}M$) and four Biotin binding sites in tetrameric Streptavidin makes this system useful for the production of multivalent antibody. For the application of this system, we cloned Streptavidin amplified from Streptomyces avidinii chromosome by PCR and fused to gene of hAY4 single-chain Fv antibody specific to death receptor 4 (DR4) which is a receptor for tumor necrosis factor ${\alpha}$ related apoptosis induced ligand. The hAY4 single-chain Fv antibody fused to Streptavidin expressed in Escherichia coli showed 43 kDa monomer in heated SDS-PAGE. However, this fusion protein shown in both non-heated SDS-PAGE and Size-exclusion chromatography exhibited 172 kDa as a tetramer suggesting that natural tetramerization of Streptavidin by non-covalent association induced hAY4 single-chain Fv tetramerization. This fusion protein retained a Biotin binding activity similar to natural Streptavidin as shown in Ouchterlony assay and ELISA. Death receptor 4 antigen binding activity of purified hAY4 single-chain Fv fused to Streptavidin was also confirmed by ELISA and Westernblot. In addition, surface plasmon resonance analysis showed 60-fold higher antigen binding affinity of the hAY4-STR than monomeric hAY4 ScFv due to tetramerization. In summary, hAY4 single-chain Fv fused to Streptavidin fusion protein was successfully expressed and purified as a soluble tetramer in E. coli and showed both Biotin and DR4 antigen binding activity suggesting possible production of bifunctional and tetrameric ScFv antibody.

• Molecules and Cells
• /
• v.39 no.2
• /
• pp.156-162
• /
• 2016

Estrogen receptor ${\alpha}$ (ER-${\alpha}$), which is involved in bone metabolism and breast cancer, has been shown to have transcriptional targets. Dlx3 is essential for the skeletal development and plays an important role in osteoblast differentiation. Various osteogenic stimulators and transcription factors can induce the protein expression of Dlx3. However, the regulatory function of ER-${\alpha}$ in the Dlx3 mediated osteogenic process remains unknown. Therefore, we investigated the regulation of Dlx3 and found that ER-${\alpha}$ is a positive regulator of Dlx3 transcription in BMP2-induced osteoblast differentiation. We also found that ER-${\alpha}$ interacts with Dlx3 and increases its transcriptional activity and DNA binding affinity. Furthermore, we demonstrated that the regulation of Dlx3 activity by ER-${\alpha}$ is independent of the ligand (estradiol) binding domain. These results indicate that Dlx3 is a novel target of ER-${\alpha}$, and that ER-${\alpha}$ regulates the osteoblast differentiation through modulation of Dlx3 expression and/or interaction with Dlx3.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2156-2164
• /
• 2017

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered as an antitumor agent owing to its ability to induce apoptosis of cancer cells without imparting toxicity toward most normal cells. TRAIL is produced in poor yield because of its insoluble expression in the cytoplasm of E. coli. In this study, we achieved soluble expression of TRAIL by fusing maltose-binding protein (MBP), b'a' domain of protein disulfide isomerase (PDIb'a'), or protein disulfide isomerase at the N-terminus of TRAIL. The TRAIL was purified using subsequent immobilized metal affinity chromatography and amylose-binding chromatography, with the tag removal using tobacco etch virus protease. Approximately 4.5 mg of pure TRAIL was produced from 125 ml flask culture with a purification yield of 71.6%. The endotoxin level of the final product was $0.4EU/{\mu}g$, as measured by the Limulus amebocyte lysate endotoxin assay. The purified TRAIL was validated and shown to cause apoptosis of HeLa cells with an $EC_{50}$ and Hill coefficient of $0.6{{\pm}}0.03nM$ and $2.41{\pm}0.15$, respectively. The high level of apoptosis in HeLa cells following administration of purified TRAIL indicates the significance and novelty of this method for producing high-grade and high-yield TRAIL.

• Journal of Life Science
• /
• v.22 no.7
• /
• pp.863-870
• /
• 2012

Rhodopsin, a dim light photoreceptor, has been regarded as one of the model systems for the structural and functional study of G protein-coupled receptors (GPCRs). Constitutively active mutant GPCRs leading to the activation of heterotrimeric GDP/GTP-binding protein signaling in the absence of ligand binding are of interest for the study of the activation mechanism in GPCRs. The present study focused on the opsin mutant E134Q/M257Y, which showed a moderate level of constitutive activity and the formation of two distinct rhodopsin chromophores with absorption maxima of 500 nm and 380 nm, depending on the presence of an inverse agonist, 11-cis-retinal, and an agonist, all-trans-retinal, respectively. Reconstitution of the mutant rhodopsin upon incubation with different ratios of 11-cis-retinal and the all-trans-retinal, as well as upon sequential binding of the two retinals, indicated its preferential binding to 11-cis-retinal. The thermal stability of the 11-cis-retinal-bound form of the E134Q/M257Y mutant was lower than that of the mutants containing a single replacement but higher than that of the all-trans-retinal-bound forms. The mutant also showed a lower stability in its opsin state as compared with that of the wild-type opsin but had little effects on the binding affinity to 11-cis-retinal. Information obtained in this study will be helpful for analyzing the structural changes associated with the activation of rhodopsin and GPCRs.

• Clinical and Experimental Reproductive Medicine
• /
• v.23 no.3
• /
• pp.247-268
• /
• 1996

It has been known for a long time that gonadotropins and steroid hormones play a pivotal role in a series of reproductive biological phenomena including the maturation of ovarian follicles and oocytes, ovulation and implantation, maintenance of pregnancy and fetal growth & development, parturition and mammary development and lactation. Recent investigations, however, have elucidated that in addition to these classic hormones, multiple growth factors also are involved in these phenomena. Most growth factors in reproductive organs mediate the actions of gonadotropins and steroid hormones or synergize with them in an autocrine/paracrine manner. The insulin-like growth factor(IGF) system, which is one of the most actively investigated areas lately in the reproductive organs, has been found to have important roles in a wide gamut of reproductive phenomena. In the present communication, published literature pertaining to the intrauterine IGF system will be reviewed preceded by general information of the IGF system. The IGF family comprises of IGF-I & IGF-II ligands, two types of IGF receptors and six classes of IGF-binding proteins(IGFBPs) that are known to date. IGF-I and IGF-II peptides, which are structurally homologous to proinsulin, possess the insulin-like activity including the stimulatory effect of glucose and amino acid transport. Besides, IGFs as mitogens stimulate cell division, and also play a role in cellular differentiation and functions in a variety of cell lines. IGFs are expressed mainly in the liver and messenchymal cells, and act on almost all types of tissues in an autocrine/paracrine as well as endocrine mode. There are two types of IGF receptors. Type I IGF receptors, which are tyrosine kinase receptors having high-affinity for IGF-I and IGF-II, mediate almost all the IGF actions that are described above. Type II IGF receptors or IGF-II/mannose-6-phosphate receptors have two distinct binding sites; the IGF-II binding site exhibits a high affinity only for IGF-II. The principal role of the type II IGF receptor is to destroy IGF-II by targeting the ligand to the lysosome. IGFs in biological fluids are mostly bound to IGFBP. IGFBPs, in general, are IGF storage/carrier proteins or modulators of IGF actions; however, as for distinct roles for individual IGFBPs, only limited information is available. IGFBPs inhibit IGF actions under most in vitro situations, seemingly because affinities of IGFBPs for IGFs are greater than those of IGF receptors. How IGF is released from IGFBP to reach IGF receptors is not known; however, various IGFBP protease activities that are present in blood and interstitial fluids are believed to play an important role in the process of IGF release from the IGFBP. According to latest reports, there is evidence that under certain in vitro circumstances, IGFBP-1, -3, -5 have their own biological activities independent of the IGF. This may add another dimension of complexity of the already complicated IGF system. Messenger ribonucleic acids and proteins of the IGF family members are expressed in the uterine tissue and conceptus of the primates, rodents and farm animals to play important roles in growth and development of the uterus and fetus. Expression of the uterine IGF system is regulated by gonadal hormones and local regulatory substances with temporal and spatial specificities. Locally expressed IGFs and IGFBPs act on the uterine tissue in an autocrine/paracrine manner, or are secreted into the uterine lumen to participate in conceptus growth and development. Conceptus also expresses the IGF system beginning from the peri-implantation period. When an IGF family member is expressed in the conceptus, however, is determined by the presence or absence of maternally inherited mRNAs, genetic programming of the conceptus itself and an interaction with the maternal tissue. The site of IGF action also follows temporal (physiological status) and spatial specificities. These facts that expression of the IGF system is temporally and spatially regulated support indirectly a hypothesis that IGFs play a role in conceptus growth and development. Uterine and conceptus-derived IGFs stimulate cell division and differentiation, glucose and amino acid transport, general protein synthesis and the biosynthesis of mammotropic hormones including placental lactogen and prolactin, and also play a role in steroidogenesis. The suggested role for IGFs in conceptus growth and development has been proven by the result of IGF-I, IGF-II or IGF receptor gene disruption(targeting) of murine embryos by the homologous recombination technique. Mice carrying a null mutation for IGF-I and/or IGF-II or type I IGF receptor undergo delayed prenatal and postnatal growth and development with 30-60% normal weights at birth. Moreover, mice lacking the type I IGF receptor or IGF-I plus IGF-II die soon after birth. Intrauterine IGFBPs generally are believed to sequester IGF ligands within the uterus or to play a role of negative regulators of IGF actions by inhibiting IGF binding to cognate receptors. However, when it is taken into account that IGFBP-1 is expressed and secreted in primate uteri in amounts assessedly far exceeding those of local IGFs and that IGFBP-1 is one of the major secretory proteins of the primate decidua, the possibility that this IGFBP may have its own biological activity independent of IGF cannot be excluded. Evidently, elucidating the exact role of each IGFBP is an essential step into understanding the whole IGF system. As such, further research in this area is awaited with a lot of anticipation and attention.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.7
• /
• pp.4347-4352
• /
• 2013

Aim: To investigate the molecular mechanisms underlying triggering of apoptosis by hesperetin using in silico and in vitro methods. Methods: The mechanism of binding of hesperetin with NF-${\kappa}B$ and other apoptotic proteins like BAX, BAD, $BCL_2$ and $BCL_{XL}$ was analysed in silico using Schrodinger suite 2009. In vitro studies were also carried out to evaluate the potency of hesperetin in inducing apoptosis using the human prostate cancer PC-3 cell line. Results: Hesperetin was found to exhibit high-affinity binding resulting from greater intermolecular forces between the ligand and its receptor NF-${\kappa}B$ (-7.48 Glide score). In vitro analysis using MTT assay confirmed that hesperetin reduced cell proliferation ($IC_{50}$ values of 90 and $40{\mu}M$ at 24 and 48h respectively) in PC-3 cells. Hesperetin also downregulated expression of the anti-apoptotic gene $BCL_{XL}$ at both mRNA and protein levels and increased the expression of pro-apoptotic genes like BAD at mRNA level and BAX at mRNA as well as protein levels. Conclusion: The results suggest that hesperetin can induce apoptosis by inhibiting NF-${\kappa}B$.