• 생명과학회지
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• 제14권5호
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• pp.732-740
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• 2004

MCM 단백질의 암세포내에서 과발현 되는 원인을 규명하기 위하여 mcm7, 2 promoter영역의 전사인자 결합 부위의 역할을 조사하였다. 암세포에서 promoter 활성은 정상세포보다 8배정도 높은 활성을 나타내 특유 전사인자의 존재를 시사하였다. Promoter영 역 에는 E2F 결합부위 와 Myc/Max/Mad단백질 결합 부위로 알려진 I-box가 존재한다. 이들 각각의 변이체 promoter를 작성하여 암세포와 정상세포에서 luciferase reporter 활성을 측정하는 것으로 각 영역의 역할을 검토하였다. 그 결과 정상세포 내에서는 강한 repressor존재 또는 활성을 negative로 조절 할 수 있는 complex의 존재로 promoter활성이 조절되는 반면 암세포 내에서는 I-box에 결합하여 promoter를 활성화시키는 특유 단백질의 존재가 시사되었다.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.659-665
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• 2016

The oligosaccharides in human milk constitute a major innate immunological mechanism by which breastfed infants gain protection against infectious diarrhea. Clostridium difficile is the most important cause of nosocomial diarrhea, and the C-terminus of toxin A with its carbohydrate binding site, TcdA-f2, demonstrates specific abolishment of cytotoxicity and receptor binding activity upon diethylpyrocarbonate modification of the histidine residues in TcdA. TcdA-f2 was cloned and expressed in E. coli BL21 (DE3). A human milk oligosaccharide (HMO) mixture displayed binding with TcdA-f2 at 38.2 respond units (RU) at the concentration of 20 μg/ml, whereas the eight purified HMOs showed binding with the carbohydrate binding site of TcdA-f2 at 3.3 to 14 RU depending on their structures via a surface plasma resonance biosensor. Among them, Lacto-N-fucopentaose V (LNFPV) and Lacto-N-neohexaose (LNnH) demonstrated tight binding to TcdA-f2 with docking energy of −9.48 kcal/mol and −12.81 kcal/mol, respectively. It displayed numerous hydrogen bonding and hydrophobic interactions with amino acid residues of TcdA-f2.

• Archives of Pharmacal Research
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• 제13권1호
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• pp.82-96
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• 1990

Ten (E)-and (Z)-isomers of 2-phenylcyclopropylamine (PCA), 1-Me PCA, 2-Me-PCA, N-Me-PCA, and N, N-diMe PCA and fifteen o-. m-, p- isomers of (E) PCA with substituents of Me, Cl, F, OMe, OH were synthesized in this laboratory and tested for the inhibition of rat brain mitochondrial MAO-A and MAO-B. The effects of substituents, their positions, and stereochemistry on the inhibition were assessed for the compounds with substituents at cyclopropyl and amino groups and QSAR analyses were performed using the potency data of ring-substituted compounds. The best correlated QSAR equations are as follows : pI$_{50}$ = 0.804 $\pi^2$-0.834 Blo-1.069 Blm + 0.334 Lp-1.709 HDp +7.897 (r = 0.945, s =0.211, F = 16.691, p = 0.000) for the inhibition of MAO-A;PI$_{50}$= 1.815$\pi$-0.825 $\pi^2$-1.203R + 0.900 Es$^2$ + 0.869 Es$^3$ + 0.796 Es$^4$-0.992 HDp + 0.562 HAo + 3.893 (r = 0.982, s =0.178, F = 23.351, p = 0.000) for the inhibition of MAO-B. Based on the potency difference between stereoisomers of cyclopropylamine-modified compounds and an QSAR cavity near para position, two hydrophobic carities interacting with Me group, a hydrophobic site near para position, and an amino group binding site and that in addition to the same two hydrophotic cavities, hydrophotic area, steric boundaries, hydrogen-acceptor site, and amino group binding site, another steric boundary near para position and a hydrogen donating site near ortho position constitute active sites of MAO-B.

• BMB Reports
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• 제51권11호
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• pp.572-577
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• 2018

Recent studies showed that the PD-1/PD-L1 checkpoint blockade is a dramatic therapy for melanoma by enhancing antitumor immune activity. Currently, major strategies for the PD-1/PD-L1 blockade have mainly focused on the use of antibodies and compounds. Seeking an alternative approach, others employ endogenous proteins as blocking agents. The extracellular domain of PD-1 (ePD1) includes the binding site with PD-L1. Accordingly, we constructed a PD-1-based recombinantly tailored fusion protein (dFv-ePD1) that consists of bivalent variable fragments (dFv) of an MMP-2/9-targeted antibody and ePD1. The melanoma-binding intensity and antitumor activity were also investigated. We found the intense and selective binding capability of the protein dFv-ePD1 to human melanoma specimens was confirmed by a tissue microarray. In addition, dFv-ePD1 significantly suppressed the migration and invasion of mouse melanoma B16-F1 cells, and displayed cytotoxicity to cancer cells in vitro. Notably, dFv-ePD1 significantly inhibited the growth of mouse melanoma B16-F1 tumor cells in mice and in vivo fluorescence imaging showed that dFv-ePD was gradually accumulated into the B16-F1 tumor. Also the B16-F1 tumor fluorescence intensity at the tumor site was stronger than that of dFv. This study indicates that the recombinant protein dFv-ePD1 has an intensive melanoma-binding capability and exerts potent therapeutic efficacy against melanoma. The novel format of the PD-L1-blocked agent may play an active role in antitumor immunotherapy.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3817-3823
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• 2014

Background: The MDM2 oncogene, a negative regulator of p53, has a functional polymorphism in the promoter region (SNP309) that is associated with multiple kinds of cancers including non-melanoma skin cancer. SNP309 has been shown to associate with accelerated tumor formation by increasing the affinity of the transcriptional activator Sp1. It remains unknown whether there are other factors involved in the regulation of MDM2 transcription through a trans-regulatory mechanism. Methods: In this study, SNP309 was verified to be associated with overexpression of MDM2 in tumor cells. Bioinformatics predicts that the T to G substitution at SNP309 generates a stronger E2F1 binding site, which was confirmed by ChIP and luciferase assays. Results: E2F1 knockdown downregulates the expression of MDM2, which confirms that E2F1 is a functional upstream regulator. Furthermore, tumor cells with the GG genotype exhibited a higher proliferation rate than TT, correlating with cyclin D1 expression. E2F1 depletion significantly inhibits the proliferation capacity and downregulates cyclin D1 expression, especially in GG genotype skin fibroblasts. Notably, E2F1 siRNA effects could be rescued by cyclin D1 overexpression. Conclusion: Taken together, a novel modulator E2F1 was identified as regulating MDM2 expression dependent on SNP309 and further mediates cyclin D1 expression and tumor cell proliferation. E2F1 might act as an important factor for SNP309 serving as a rate-limiting event in carcinogenesis.

• 한국자기학회지
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• 제14권1호
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• pp.46-50
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• 2004

자성 garnet $Y_3$F $e_{5}$ $O_{12}$의 Y자리에 Ce이 치환된 $Y_{3-x}$C $e_{x}$F $e_{5}$ $O_{12}$(x=0.0, 0.1, 0.2, 0.3) 분말을 졸-겔법으로 합성하였다. $Y_{3-x}$C $e_{x}$F $e_{5}$ $O_{12}$의 결정학적 자기적 성질을 X-선 회절기(XRD), 진동시료 자화율 측정기(VSM)및 Mossbauer분광기를 이용하여 연구하였다. $Y_{3-x}$C $e_{x}$F $e_{5}$ $O_{12}$의 결정구조는 cubic이며, 격자상수는 x = 0.0에서 0.3까지 치환하였을 때 12.3758 $\pm$ 0.0005 $\AA$부터 12.4062 $\pm$ 0.0005 $\AA$으로 선형적으로 증가함을 보였다. VSM 측정 결과 $Y_{3-x}$C $e_{x}$F $e_{5}$ $O_{12}$의 포화 자화(saturation magnetization) 값은 거의 변화가 없었던 반면, 보자력(coercivity) 값은 $Y_3$F $e_{5}$ $O_{12}$과 $Y_{2.9}$C $e_{0.1}$F $e_{5}$ $O_{12}$일때 각각 18.3 Oe에서 5.8 Oe로 감소하였다. 이들 시료의 Mossbauer spectrum을 13K부터 Neel온도까지 측정을 하였다. Fe원자 위치의 분포를 고려하여 16a와 24d에 site의 2set으로 분석하였으며, 또한 $Y_{3-x}$C $e_{x}$F $e_{5}$ $O_{12}$의 자성 이온간의 상호작용을 Neel 이론으로 해석할 수 있었으며 개별 부격자간의 초교환 상호작용의 세기를 결정하였다. Debye 온도를 분석 결과 24d site 의 고체의 굳기가 16a site 경우보다 더 큰 것으로 분석 되었다.te 의 고체의 굳기가 16a site 경우보다 더 큰 것으로 분석 되었다.다. 분석 되었다.다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.581-588
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• 2007

To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.

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

• Journal of Microbiology and Biotechnology
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• 제2권1호
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• pp.56-65
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• 1992

The complete nucleotide sequence of the Bacillus circulans F-2 RSDA gene, coding for raw starch digesting a-amylase (RSDA), has been determined. The RSDA structure gene consists of an open reading frame of 2508 bp. Six bp upstream of the translational start codon of the RSDA is a typical gram-positive Shine-Dalgarno sequence and the RSDA encodes a preprotein of 836 amino acids with an Mr of 96, 727. The gene was expressed from its own regulatory region in E. coli and two putative consensus promoter sequences were identified upstream of a ribosome binding site and an ATG start codon. Confirmation of the nucleotide sequence was obtained and the signal peptide cleavage site was identified by comparing the predicted amino acid sequence with that derived by N-terminal analysis of the purified RSDA. The deduced N-terminal region of the RSDA conforms to the general pattern for the signal peptides of secreted prokaryotic proteins. The complete amino acid sequence was deduced and homology with other enzymes was compared. The results suggested that the Thr-Ser-rich hinge region and the non-catalytic domain are necessary for efficient adsorption onto raw substrates, and the catalytic domain (60 kDa) is necessary for the hydrolysis of substrates, as suggested in previous studies (8, 9).

• Molecules and Cells
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• 제44권2호
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• pp.88-100
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• 2021

Anoctamin 6/TMEM16F (ANO6) is a dual-function protein with Ca2+-activated ion channel and Ca2+-activated phospholipid scramblase activities, requiring a high intracellular Ca2+ concentration (e.g., half-maximal effective Ca2+ concentration [EC50] of [Ca2+]i > 10 μM), and strong and sustained depolarization above 0 mV. Structural comparison with Anoctamin 1/TMEM16A (ANO1), a canonical Ca2+-activated chloride channel exhibiting higher Ca2+ sensitivity (EC50 of 1 μM) than ANO6, suggested that a homologous Ca2+-transferring site in the N-terminal domain (Nt) might be responsible for the differential Ca2+ sensitivity and kinetics of activation between ANO6 and ANO1. To elucidate the role of the putative Ca2+-transferring reservoir in the Nt (Nt-CaRes), we constructed an ANO6-1-6 chimera in which Nt-CaRes was replaced with the corresponding domain of ANO1. ANO6-1-6 showed higher sensitivity to Ca2+ than ANO6. However, neither the speed of activation nor the voltage-dependence differed between ANO6 and ANO6-1-6. Molecular dynamics simulation revealed a reduced Ca2+ interaction with Nt-CaRes in ANO6 than ANO6-1-6. Moreover, mutations on potentially Ca2+-interacting acidic amino acids in ANO6 Nt-CaRes resulted in reduced Ca2+ sensitivity, implying direct interactions of Ca2+ with these residues. Based on these results, we cautiously suggest that the net charge of Nt-CaRes is responsible for the difference in Ca2+ sensitivity between ANO1 and ANO6.