• Textile Coloration and Finishing
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• v.10 no.5
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• pp.32-38
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• 1998

Glycolides were polymerized by PPG or Pluronic(PN) to give A-B-A block copolyesters consisting of polyglycolide(A) and polypropylene glycol(B) or polyglycolide(A) and PN (B). Lactones were easily copolymerized with polyethers by ester interchange reaction even in the absence of catalyst. It is because PPG and PN are telechelic polyethers having hydroxy groups on their both ends. When the feed ratio of PPG(M$_{n}$=4,000) and PN(M$_{n}$=11,500) were over 5 and 10 wt% .elative to glycolide, respectively, the polymerization of glycolide took place from the terminus hydroxy groups of PPG or PN to produce the desired A-B-A block copolymers in high yields. The molecular weights of the copolymers, which estimated from the monomer conversions and the feed ratios of PPG and PN, could be controlled by changing the kind of terminus hydroxy of polyether and the feed molar ratio of PPG and PN. PN.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1484-1490
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• 2010

In the Streptomyces hygroscopicus JCM4427 geldanamycin biosynthetic gene cluster, five putative regulatory genes were identified by protein homology searching. Among those genes, gel14, gel17, and gel19 are located downstream of polyketide synthase genes. Gel14 and Gel17 are members of the LAL family of transcriptional regulators, including an ATP/GTP-binding domain at the N-terminus and a DNA-binding helix-turn-helix domain at the C-terminus. Gel19 is a member of the TetR family of transcriptional regulators, which generally act to repress transcription. To verify the biological significance of the putative regulators in geldanamycin production, they were individually characterized by gene disruption, genetic complementation, and transcriptional analyses. All three genes were confirmed as positive regulators of geldanamycin production. Specifically, Gel17 and Gel19 are required for gel14 as well as gelA gene expression.

• Biomolecules & Therapeutics
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• v.14 no.2
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• pp.96-101
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• 2006

Amyloid$\beta(A{\beta})$ has been reported have an effect on the induction of oxidative stress that involves the functional and structural abnormalities in Alzheimer's disease. As a role of a radical scavenger, a green tea treatment was found have some inhibitory effect on the neurodegenerative process. The aim of this study was to determine if green tea catechin (GTC) reduces in transgenic model. To test this, transgenic mice carrying neuronspecific enolase (NSE) controlled C-terminus (105) of APP (APP-C105) were created and treated them with a low ana high dose of GTC for 6 months. Herein, we conclude that transgenic mice expressing NSE/APP-C105 were successfully created and the GTC-treated group exhibited significant reduction in body weight. Thus, GTC might be a good prevention of obesity or good treatment for AD patient.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1441-1447
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• 2006

The light perception and phototransformation of phytochromes are the first process of the phytochrome-mediated light signal transduction. The chromophore ligation and its photochromism of various site-specific and deletion mutants of pea phytochrome A and bacterial phytochrome-like protein (Cph1) were analyzed in vitro. Serial truncation mutants from the N-terminus and C-terminus indicated that the minimal N-terminal domain for the chromophore ligation spans from the residue 78 to 399 of pea phytochrome A. Site-specific mutants indicated that several residues are critical for the chromophore ligation and/or photochromism. Histidine-324 appears to serve as an anchimeric residue for photochromism through its H-bonding function. Isoleucine-80 and arginine-383 playa critical role for the chromophore ligation and photochromism. Arginine-383 is presumably involved in the stabilization of the Pfr form of pea phytochrome A. Apparently, the amphiphilic ${\alpha}$-helix centered around the residue-391 is in the chromophore pocket and critical for the chromophore ligation.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.381-385
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• 1999

Taq DNA polymerase from Thermus aquaticus has been shown to be very useful in a polymerase chain reaction. Taq DNA polymerase has a domain at the amino terminus (residues 1 to 290) that has 5'-3' exonuclease activity and a domain at the C-terminus that catalyzes the polymerase reaction. Taq DNA polymerase is classified into the Pol I family, which is represented by E. coli DNA polymerase I. The alignment of amino acid sequences for the 5'-3' exonuclease domains of the Pol I family DNA polymerases shows ten highly conserved carboxylic amino acids. Crystallographic studies suggested that six of the carboxylic amino acids are clustered within a 7 $\AA$ radius by chelating three metal ions in the active site. Those six carboxylic residues are mutagenized to alanines in order to better understand their function. All six carboxylic residues, Asp l8, Glu1l7, Asp1l9, Asp120, Asp142, and Aspl44, are crucial for catalysis of 5'-3' exonuclease.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.58-58
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• 2003

The envelope glycoprotein of HIV, gp41, mediates the membrane fusion with human cells. The extracellular domain of gp41 has two helical regions. The N-terminus helical region (N-helix) forms trimeric coiled coil, interacts with the C-terminus helical region (C-helix) of gp41 to form a stable helical bundle structure. In this study, we have shown that the N-helix of gp41 has membrane interacting and disrupting abilities. It was localized into the interface of the lipidic phase and head group of the membrane. In contrast, the N-helix region with membrane fusion defective mutations could not bind to membrane. In addition, the N-helix bound on the membrane was released from the membrane by the C-helix, and the complex of the N- and C-helix did not interact with membrane. These results suggested that the membrane binding ability of the N-helix is necessary for the fusion activity of gp41, and such property is possibly controlled by the C-helm.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.139-145
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• 2020

Polo-like kinase 1 (Plk1) is a key protein in mitosis and has been validated as a target for tumor therapy. It is well known to highly overexpress in many kinds of tumor, which has been implicated as a potential biomarker for tumor treatment and diagnosis. Plk1 consists of two domains, the N-terminus kinase domain and the C-terminus polo-box domain (PBD). The inhibitors have been developed for PBD of Plk1, which were shown a high level of affinity and selectivity for Plk1 that led to mitotic arrest and apoptotic cell death. This review discusses the inhibitors for PBD of Plk1 that are suitable for in vivo tumor treatment. They can be further extended for developing in vivo imaging probes for early diagnosis of tumor.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.374-378
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• 1997

Glutathione S-transferase (GST) was purified from Pseudomonas sp. DJ77, and its N-terminal sequence was determined to be MKLFISPGACSL. A specific tyrosyl residue in the vicinity of the N terminus is conserved in all the known cytosolic GSTs and has been shown to function as a catalytic residue in $\alpha$, $\mu$, $\pi$ class GSTs from mammals. However, Pseudomonas sp. DJ77 GST has the Phe-4 and Ile-5 instead of Tyr in N-terminus. Its replacement with tyrosine did not significantly affect the enzyme activity. Results from in vitro biochemical analyses were confirmed by the in vivo activity-based CDNB growth inhibition analyses. Our results clearly indicate that GST of Pseudomonas sp. DJ77 has a novel reaction mechanism different from that of mammalian GSTs.

• 대한약리학회:학술대회논문집
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• 2006.10a
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• pp.114.1-114.1
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• 2006

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.932-934
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• 2000