• BMB Reports
• /
• 제34권6호
• /
• pp.537-543
• /
• 2001

In the present study, an in vitro ELISA system to assess the interaction between Src homology (SH)2 domains and phosphotyrosine that contain peptides was established using purified GST-conjugated SH2 proteins and synthetic biotinylated phosphotyrosine that contain oligopeptides. The SH2 domains bound the relevant phosphopeptides that were immobilized in the streptavidin-coated microtiter plate in a highly specific and dose-dependent manner. The epidermal growth factor receptor (EGFR)-, T antigen (T Ag)-, and platelet-derived growth factor receptor (PDGFR)-derived phosphopeptides interacted with the growth factor receptor binding protein (Grb)2/SH2, Lck/SH2, and phosphatidyl inositol 3-kinase (PI3K) p85/SH2, respectively. No cross-reactions were observed. Competitive inhibition experiments showed that a short phosphopeptide of only four amino acids was long enough to determine the binding specificity. Optimal concentrations of the GST-SH2 fusion protein and phosphopeptide in this new ELISA system for screening the binding blockers were chosen at 2nM and 500nM, respectively. When two candidate compounds were tested in our ELISA system, they specifically inhibited the Lck/SH2 and/or p85/SH2 binding to the relevant phosphopeptides. Our results indicate that this ELISA system could be used as an easy screening method for the discovery of specific binding blockers of protein-protein interactions via SH2 domains.

• BMB Reports
• /
• 제36권2호
• /
• pp.207-213
• /
• 2003

Peroxisome proliferator-activated receptors (PPARs) are orphan nuclear hormone receptors that are known to control the expression of genes that are involved in lipid homeostasis and energy balance. PPARs activate gene transcription in response to a variety of compounds, including hypolipidemic drugs. Most of these compounds have high affinity to the ligand-binding domain (LBD) of PPARs and cause a conformational change within PPARs. As a result, the receptor is converted to an activated mode that promotes the recruitment fo co-activators such as the steroid receptor co-activator-1 (SRC-1). Based on the activation mechanism of PPARs (the ligand binding to $PPAR{\gamma}$ induces interactions of the receptor with transcriptional co-activators), we performed Western blot and ELISA. These showed that the indomethacin, a $PPAR{\gamma}$ ligand, increased the binding between $PPAR{\gamma}$ and SRC-1 in a ligand dose-dependent manner. These results suggested that the in vitro conformational change of $PPAR{\gamma}$ by ligands was also induced, and increased the levels of the ligand-dependent interaction with SRC-1. Collectively, we developed a novel and useful ELISA system for the mass screening of $PPAR{\gamma}$ ligands. This screening system (based on the interaction between $PPAR{\gamma}$ and SRC-1) may be a promising system in the development of drugs for metabolic disorders.

• 대한수의학회지
• /
• 제44권2호
• /
• pp.251-257
• /
• 2004

This study was designed to determine optimal condition for expression of cloned Shigatoxin2e(Stx2e) gene from transformed E. coli PED18, to compare the cytotoxicity titer between cloned Stx2e and Stx2e from original strain, and to confirm of receptor binding affinity of Stx2e for use of development of receptor binding ELISA to detect of Stx2e. The optimum composition of medium for expression of Stx2e gene in E.coli host-vector system was definded as the medium containing 0.5% glucose and 0.5 mM IPTG. The cytotoxicity titer of expressed Stx2e for Vero cell was 1000 fold higher than that of Stx2e from original strain AY93258. The binding affinity of Stx2e to receptor globotetraosyl ceramide($Gb_4$) was confirmed by immunobloting.

• 한국양식학회지
• /
• 제15권1호
• /
• pp.31-37
• /
• 2002

이 연구는 무지개송어, O. mykiss 간세포 배양을 이용해 합성화학물질인 2,4-Dichlorophenoxy acetic acid (2,4-D)가 vitellogenin (VTG) 합성과 estrogen (E$_2$) - estrogen receptor (ER) binding affinity에 미치는 영향을 조사하였다. 간세포는 2일간 전 배양한 후에 E, (2$\times$10$\^$-6/ M) 또는 2,4-D (10$\^$-9/∼10$\^$-6/ M)를 배지에 첨가해 5일간 배양한 후, VTG과 E$_2$-ER binding affinity를 SDS-PAGE와 ELISA를 이용해 각각 조사하였다. 사용된 2,4-D의 농도는 세포의 형태, 생존력 및 DNA 함량에는 영향을 미치지 않았다. 또한, 2,4-D는 VTG의 합성에도 어떠한 영향도 미치지 않았으나 E$_2$-ER binding affinity를 억제하였다. 이 binding affinity는 2,4-D의 농도가 증가할수록 증가하는 경향을 나타내어 10$\^$-7/과 10$\^$-6/ M에서 25%와 30%를 각각 억제하였다. 이 결과들은 비록 2,4-D가 VTG의 합성에는 영향을 미치지 않지만, ER에서 xeno-estrogenic contaminant로서 행동하는 것을 제시하였다.

• 미생물학회지
• /
• 제52권1호
• /
• pp.10-17
• /
• 2016

항체의 특이적 결합을 분석하는 효소면역분석법은 항원의 탐지를 위해 주로 horseradish peroxidase (HRP) 또는 alkaline phosphatase (AP) 등의 효소를 사용한다. 이때 효소를 주로 화학적으로 항체에 결합시켜 사용하게 되는데 이 과정이 복잡하며 불규칙하게 일어나서 항체 및 효소의 기능을 감소시키게 된다. 또한 대부분의 효소면역분석법에서는 주로 일차 항체의 항원결합을 탐지하기위해 이차 항체를 사용하는데, 즉 이차 항체에 결합한 효소의 기질발색에 의해 일차 항체의 항원결합을 탐지하므로 이차 항체가 요구 되어질 뿐만 아니라 이차 항체의 일차 항체에 대한 반응을 위한 부가적인 배양시간이 필요하다. 더욱 더 중요한 것은 이차 항체만의 비특이적 항원 결합 역시 제거되어져야 한다. 본 연구에서는 대장균의 genomic DNA로부터 PCR을 통해 alkaline phosphatase 유전자(Sadeghi et al., 2008)를 증폭 분리한 다음 이를 TRAIL (tumor necrosis factor ${\alpha}$ related apoptosis induced ligand) receptor인 death receptor 4 (DR4)에 특이적으로 결합하는 hAY4 single-chain Fv (ScFv)에 융합시킨 재조합 ScFv-AP 형태로 대장균에서 발현시켜 정제하였다. 정제된 hAY4 ScFv-AP는 SDS-PAGE에서 단량체(monomer) 분자량인 73.8 kDa을 나타내었다. 그러나 size-exclusion chromatography(SEC)에서는 147.6 kDa을 나타내는 결과를 통해 hAY4 ScFv-AP는 AP의 자연적인 비공유결합에 의해 이량체(dimeric form)형성이 유도되어짐을 확인하였다. 또한 ELISA, Western blot 그리고 immunocytochemistry에서 이차 항체 없이 일차 항체 hAY4 ScFv에 직접 융합된 AP의 기질발색에 의해 ScFv 일차 항체의 특이적 항원결합을 나타내었다. 요약하면 hAY4 ScFv와 대장균의 alkaline phosphatase 유전자를 융합시켜 대장균에서 수용성 형태로 성공적으로 정제하였으며 정제된 ScFv-AP 융합단백질은 ELISA, Western blot 및 immunocytochemistry에서 항원결합력을 나타냈으며 또한 구매에 따른 고비용, 부가적인 배양시간 및 비특이적 결합에 의한 오류 등의 문제점을 갖는 이차 항체를 사용하지 않고 직접적인 항원결합력을 나타내었다.

• 미생물학회지
• /
• 제54권4호
• /
• pp.330-342
• /
• 2018

Streptavidin (STR)과 Biotin system은 Biotin의 Streptavidin에 대한 높은 비공유 친화력(non-covalent affinity; $K_D=10^{-14}M$)과 4 Biotin 결합부위를 갖는 Streptavidin의 tetramer 구조로 인해 복수의 항원결합부위 및 복수의 항원특이성을 갖는 항체를 제조할 수 있기 때문에 가장 활발하게 연구되고 있다. 이 system을 활용하기 위해 우리는 Streptomyces avidinii 염색체 DNA로부터 PCR을 통해 Streptavidin (STR) 유전자를 증폭하고 이를 TRAIL (tumor necrosis factor ${\alpha}$ related apoptosis induced ligand) receptor인 death receptor 4 (DR4)에 특이적으로 결합하는 hAY4 single-chain Fv 항체유전자에 융합시켰다. 대장균에서 발현시킨 STR에 융합된 hAY4 ScFv (hAY4-STR) 항체는 가열시킨 SDS-PAGE에서 43 kDa monomer를 나타내었다. 그러나 가열하지 않은 SDS-PAGE와 Size-exclusion chromatography에서는 tetramer인 172 kDa을 나타내었는데 이는 hAY4 ScFv-STR 항체가 STR의 자연적인 비공유결합에 의해 유도된 tetramer를 형성하고 있음을 나타내고 있다. 본 융합 단백질은 Ouchterlony assay와 ELISA에서 보여주는 것처럼 자연 Streptavidin과 유사한 Biotin 결합력을 유지하고 있었다. ELISA와 Westernblot을 이용하여 정제된 hAY4-STR 융합항체의 DR4 항원결합력 또한 확인하였다. 게다가 표면 플라즈몬 공명(surface plasmon resonance) 분석에서 hAY4 ScFv-STR tetramer는 tetramerization에 의해 hAY4 ScFv monomer보다 60배 더 높은 항원결합력을 나타내었다. 요약하면 hAY4 ScFv-STR 융합단백질은 E. coli에서 soluble tetramer로 성공적으로 발현 및 정제되었으며 Biotin과 DR4 항원에 동시에 결합함을 보여 주었다. 이는 bifunctional and tetrameric ScFv 항체를 제조 할 수 있음을 제시해 주고 있다.

• Biomolecules & Therapeutics
• /
• 제3권4호
• /
• pp.266-272
• /
• 1995

The analysis of membrane receptors for hormones and neurotransmitters has progressed considerably by pharmacological and biochemical means and more recently through the use of specific antibodies. To generate and characterize a moloclonal antibody against $\beta$-adrenergic receptor, a synthetic $\beta$2-adrenergic receptor peptide (Phe-Gly-Asn-Phe-Trp-Cys-Phe-Trp-Thr-Ser-lle-Asp-Val-Leu) which may comprise part of $\beta$-adrenergic receptor ligand binding pocket was coupled to Keyhole Limpet Hemocyanin (KLH) and used as an immunogen. Male BALB/C mice were immunized with this antigen and the immunized spleen was fused with myeloma SP2/0-Ag14 cells to produce monoclonal antibodies. Two clones were obtained but one of monoclonal antibodies, mAb5G09, was used throughout in this study because the other clone, mAb5All showed weak immunoreactivity against KLH as well. The mouse monoclonal antibody mAb5G09 produced in this study showed immunoreactivity to peptide-KLH conjugates and also to human A43l cells and guinea pig lung $\beta$2-adrenergic receptor as revealed by ELISA and western blot. In the course of determination of the effects of mAb5G09 on $\beta$-receptor ligand binding, it was observed that mAb5G09 specifically bound $\beta$-adrenergic radioligand [$^3$H]dihydroalprenolol (DHA) with a dissociation constant (Kd) of 60 nM. The [$^3$H]DHA binding activity of mAb5G09 had characteristics of immunoglobulins and the binding activity was not observed in the control anti-KLH monoclonal antibody. The monoclonal antibody, mAb5G09 produced in this study may provide useful models for the study of the structure of receptor binding sites.

• Journal of Microbiology and Biotechnology
• /
• 제27권7호
• /
• pp.1336-1344
• /
• 2017

Hepatitis B virus (HBV) is a major cause of liver cirrhosis and hepatocellular carcinoma. With recent identification of HBV receptor, inhibition of virus entry has become a promising concept in the development of new antiviral drugs. To date, 10 HBV genotypes (A-J) have been defined. We previously generated two murine anti-preS1 monoclonal antibodies (mAbs), KR359 and KR127, that recognize amino acids (aa) 19-26 and 37-45, respectively, in the receptor binding site (aa 13-58, genotype C). Each mAb exhibited virus neutralizing activity in vitro, and a humanized version of KR127 effectively neutralized HBV infection in chimpanzees. In the present study, we constructed a humanized version (HzKR359-1) of KR359 whose antigen binding activity is 4.4-fold higher than that of KR359, as assessed by competitive ELISA, and produced recombinant preS1 antigens (aa 1-60) of different genotypes to investigate the binding capacities of HzKR359-1 and a humanized version (HzKR127-3.2) of KR127 to the 10 HBV genotypes. The results indicate that HzKR359-1 can bind to five genotypes (A, B, C, H, and J), and HzKR127-3.2 can also bind to five genotypes (A, C, D, G, and I). The combination of these two antibodies can bind to eight genotypes (A-D, G-J), and to genotype C additively. Considering that genotypes A-D are common, whereas genotypes E and F are occasionally represented in small patient population, the combination of these two antibodies might block the entry of most virus genotypes and thus broadly neutralize HBV infection.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1995년도 춘계학술대회
• /
• 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.

• 약학회지
• /
• 제37권4호
• /
• pp.420-426
• /
• 1993

To effectively purify of IL-1 inhibitor from human febrile urine, we have established monoclonal antibody that reacts with human recombinant interleukin l$\beta$(IL-1$\beta$). The antibody, designated ON-1, was highly specific to IL-1$\beta$ and no cross-reaction with other cytokines(IL-l$\alpha$ and IL-4) was observed. As the results of ELISA inhibition assay and Western blotting method, it was further identified that ON-1 had high binding specificity with IL-1$\beta$. IL-1 receptor binding material from febrile patient urine was effectively purified with affinity column chromatography which conjugated with ON-1. This urinary material inhibited the thymocyte proliferation in a dosedependent manner. IL-l$\beta$ induced thymocyte proliferation activity was inhibited to 67.3% at 6 $\mu\textrm{g}$ of the purified urinary material. The result may suggest that this urinary material the purified urinary material. The result may suggest that this urinary material will have antagonic effect on IL-1 action mechanism and act IL-l$\beta$ inhibitor.