• Journal of Periodontal and Implant Science
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• 제29권3호
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• pp.663-676
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• 1999

Porphyromonas gingivalis, a Gram negative, anaerobic, asaccharolytic rod, is one of the most frequently implicated pathogens in human periodontal disease and has a requirement for hemin for growth. A 30 kDa (heated 24 kDa) hemin-binding protein whose expression is both hemin and iron regulated has recently been purified and characterized in this oral pathogen. This study has identified a hemin-binding P. gingivalis protein by expression of a P. gingivalis genomic library in Escherichia coli, a bacterium which does not require or transport exogenous hemin. A library of genomic DNA fragments from P. gingivalis was constructed in plasmid pUC18, transformed into Escherichia coli strain $DH5{\alpha}$ , and screened for recombinant clones with hemin-binding activity by plating onto hemin-containing agar. Of approximately 10,000 recombinant E. coli colonies screened on LB-amp-hemin agar, 10 exhibited a clearly pigmented phenotype. Each clone contained various insert DNA. The Hind III fragment transferred to the T7 RNA polymerase/promoter expression vector system produced a sligltly smaller (21 kDa) protein, a precursor form, immunoreactive to the antibody against the 24 kDa protein, suggesting that the cloned DNA fragment probably carried an entire gene for the 24 kDa hemin-binding protein.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.925-928
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• 1999

The process of transcription is the major point at which gene expression is regulated. The jun and fos families of eukaryotic transcription factor heterodimerize to form complexes capable of binding 5'-TGAGTCA-3'DNA elements (AP-1 binding site). To search for the inhibitors of the jun-fos-DNA complex formation, several natural products extracts were screened and methanol extract of tanshen (the dried roots of Salvia miltiorrhiza Bunge) showed remarkable inhibitory activity. The active compounds of the extracts were purified using re-peated column chromatography and recrystallization. Their structures were identified as tanshinone I and tanshinone IIA. Through the electrophoresis mobility shift assay and cell cytotoxicity test, tanshinone I and tanshinone IIA were identified as inhibitors that suppress not only AP-1 function but also the cell proliferation. Tanshinone I also suppressed the jun-fos-DNA complex formation in TPA-induced NIH 3T3 cells.

• Nutritional Sciences
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• 제8권1호
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• pp.23-27
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• 2005

The major garlic component, Allicin [diallylthiosulfinate, or (R, S)-diallyldissulfid-S-oxide] is known for its medicinal effects, such as antihypertensive activity, microbicidal activity, and antitumor activity. Allicin and diallyldisulfide, which is a converted form of allicin, inhibited the cholesterol level in hepatocytes, in vivo and in vitro. The metabolism of allicin reportedly occurs in the microsomes of hepatocytes, predominantly with the contribution of cytochrome P-450. However, little is known about how allicin affects the genes involved in the activity of hepatocytes in vivo. In the present study, we used the short-term intravenous injection of allicin to examine the in vivo genetic profile of hepatocytes. Allicin up-regulate ten genes in the hepatocytes. For example, the interferon regulator 1 (IRF-I), the wingless-related MMTV (mouse mammary tumor virus) integration site 4 (wnt-4), and the fatty acid binding protein 1. However, allicin down-regulated three genes: namely, glutathione S-transferase mu6, a-2-HS glycoprotein, and the corticosteroid binding globulin of hepatocytes. The up-regulated wnt-4, IRF-1, and mannose binding lectin genes can enhance the growth factors, cytokines, transcription activators and repressors that are involved in the immune defense mechanism. These primary data, which were generated with the aid of the Atlas Plastic Mouse 5 K Microarray, help to explain the mechanism which enables allicin to act as a therapeutic agent, to enhance immunity, and to prevent cancer. The data suggest that these benefits of allicin are partly caused by the up-regulated or down-regulated gene profiles of hepatocytes. To evaluate the genetic profile in more detail, we need to use a more extensive mouse genome array.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1875-1878
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• 2013

• 약학회지
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• 제53권4호
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• pp.228-234
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• 2009

Topoisomerase I (Topo I) participates in the DNA replication, transcription, and repair. Binding of Topo I inhibitor to the Topo I-DNA cleavage complex forms stabilized ternary complex which blocks DNA religation and ultimately causes cell death. Camptothecin (CPT) and its derivatives have been among the most effective anticancer drugs by inhibition of topo I. However, efforts to synthesize non-CPT drugs have been actively going on because the CPT derivatives have several limitations such as poor solubility, short half-life, and side effects. As an indenoisoquinoline, NSC314622 is not as potent as CPT, but its chemical stability and slower reversibility of the cleavage complex made it a good lead compound. Recently, a series of indenoisoquinoline analogues were synthesized with substituted dimethoxy or methylenedioxy on the aromatic ring and alkylamino on the lactam nitrogen. Some of them showed quite good Topo I inhibitory activity. Using the computer docking program, Surflex-Dock, indenoisoquinoline analogues were docked into the human Topo I-DNA cleavable complex. The docking results showed that the compounds with activity better than NSC314622 intercalated between the -1 and +1 base pairs at the cleavage site, but those with little or no activities did not appear to intercalate. These results could be useful to design new Topo I inhibitors improved than CPT.

• Animal cells and systems
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• 제10권1호
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• pp.1-6
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• 2006

Previous studies showed that Cdc7 kinase of Schizosaccharomyces pombe phosphorylated the minichromosome maintenance (Mcm) complex efficiently in the presence of spMcm10 protein. The biochemical properties of the phosphorylated Mcm complexes were examined to understand the activation mechanism of the Mcm complex by Cdc7 kinase. The phosphorylation of Mcm complex in the presence of spMcm10 by Cdc7 kinase did not affect the stability of the Mcm complex containing all six subunits, and the changes in the sedimentation properties were not observed after the phosphorylation. The reconstitution of the Mcm complex using the purified proteins showed that the phosphorylation of Mcm2 proteins did not affect the interactions between Mcm proteins. The phosphorylation of the Mcm2-7 complex at the same condition also did not activate the other biochemical activities such as DNA helicase and single stranded (ss) DNA binding activities. On the other hand, spMcm10 protein that was used for the stimulation of Mcm phosphorylation showed single stranded DNA binding activity, and inhibited the DNA helicase activity of the Mcm4/6/7 complex. These inhibitory effects were reduced by the addition of Cdc7 kinase, suggesting that the phosphorylation by Cdc7 kinase decreased the interactions between spMcm10 and the Mcm complex. Taken together, these results suggested that the phosphorylation by Cdc7 kinase alone is not sufficient for the remodeling and the activation of the Mcm complex, and the additional factors or the phosphorylations might be required for the activation of the Mcm complex.

• 미생물학회지
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• 제33권2호
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• pp.118-124
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• 1997

이전의 연구에서 우리는 CheY-OmpR 융합단백질인 'Chp'을 제조하여 ompF와 ompC 유전자에 미치는 영향을 조사하였다(6). 본 연구에서는 Chp의 활성 및 작용기작을 in vivo와 in vitro 실험을 통해 알아보았다. 융합단백질 Chp은 OmpR과 마찬가지로 DNA에 염기서열 특이적인 결합을 하지만, 유전자의 전사 활성 기능은 나타내지 않았다. 따라서 Chp의 ompF/C 유전자의 발현에 대한 효과는 DNA 결합 부위에 대한 OmpR과의 경쟁에 의해 나타나는 것으로 결론지을 수 있다. 그러나, in vivo와 in vitro 실험에서 Chp의 인산화에 따른 DNA 결합력 변화는 관찰할 수 없었다. Chp이 ompR 유전자의 발현을 증가시키는 것이 관찰되었는데, OmpR도 이와 같은 효과를 나타내었으며, 배지의 삼투압을 변화시켰을 때와 EnvZ 돌연변이체에서도 ompR 유전자의 발현변화가 관찰되었다.

• Animal cells and systems
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• 제6권4호
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• pp.311-315
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• 2002

The RAD4 gene is essential for nucleotide excision repair in Saccharomyces cerevisiae. It has been known that the deduced amino acid sequence of Rad4 protein contains three DNA-dependent ATPase/helicase motifs. To determine the biochemical activities and functional role of RAD4 the Rad4 protein was expressed and purified. Immunoblot analysis showed a specific band of 21 kDa, which was well-matched with the size of open reading frame of the RAD4 gene. The purified Rad4 protein had no detectable helicase activity. However, the protein could interact with double stranded oligonucleotides, as judged by mobility shift assay. This result suggests that the Rad4 protein is a DNA binding protein.

• 약학회지
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• 제42권1호
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• pp.46-52
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• 1998

Retroviral integrase is required for integration of viral DNA into the host cell chromosome. Human immunodeficiency virus type-1 integrase was partially purified as a part of a fusion protein linked to a maltose-binding protein and characterized in terms of an endonucleolytic activity. The concentration of the fusion protein purified through an amylose column was about 12mg/ml. Indicating that the solubility of the fusion protein is highly increased by the presence of a maltose-binding protein, considering that the integrase protein alone is poorly solubilized. The endonucleolytic activity of the fusion protein was detected at 0.1 to 1.OmM $Mn^{++}$ ion, but not at any concentrations tested of $Mn^{++}$ ion.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.51-56
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• 1999

Plastids, which are organelles unique to plant cells, bear their own genome that is organized into DNA-protein complexes (nucleoids). Regulation of gene expression in the plastid has been extensively investigated because this organelle plays an important role in photosynthesis. Few attempts, however, have been made to characterize the regulation of plastid gene expression at the chromosomal structure, using plastid nucleoids. In this report, we summarize the recent progress in the characterization of DNA-binding proteins in plastids, with special emphasis on CND41, a DNA binding protein, which we recently identified in the choloroplast nucleoids from photomixotrophically cultured tobacco cells. CND41 is a protein of 502 amino acids which consisted of a transit peptide of 120 amino acids and a mature protein of 382 amino acids. The N-terminal of the 'mature' protein has lysine-rich region which is essential for DNA-binding. CNA41 also showed significant identities to some aspartyl proteases. Protease activity of purified CND41 has been recently confirmed and characterized. On the other hand, characterization of accumulation of CND41 both in wild type and transgenic tobacco with reduced amount of CND41 suggests that CND41 is a negative regulator in chloroplast gene expression. Further investigation indicated that gene expression of CND41 is cell-specifically and developmentally regulated as well as sugar-induced expression. The reduction of CND41 expression in transgenic tobacco also brought the stunted plant growth due to the reduced cell length in stem. GA3 treatment on apical meristem reversed the dwarf phenotype in the transformants. Effects of CND41 expression on GA biosynthesis will be discussed.