• Corrosion Science and Technology
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• v.7 no.6
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• pp.307-314
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• 2008

The influence of a moist atmosphere on $90^{\circ}$ domain switching under a sustained electric field, stress corrosion cracking of an indentation crack in water and an aggressive solution, and the relation between penetrating crack propagation and domain switching were studied using $BaTiO_3$ single crystal. The results indicate that enlarging the domain switching zone and crack propagation could be facilitated by a moist atmosphere or an aggressive solution due to the indentation residual stress. A moist atmosphere exerts remarkable influence upon the polarization of $BaTiO_3$ single crystal under a sustained electric field, and the surface energy of the c domain was much lower than that of the a domain. Domain switching ahead of a penetrating indentation crack tip was an essential requirement for crack propagation under constant stress.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.281-284
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• 2012

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.95-98
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• 2015

Reverse gyrase is a hyperthermophile specific protein which introduces positive supercoils into DNA molecules. Reverse gyrase consists of an N-terminal helicase-like domain and a C-terminal topoisomerase domain. The helicase-like domain shares the three-dimensional structure with two tandem RecA-folds (H1 and H2), in which the subdomain H2 is interrupted by the latch domain (H3). To understand the physical property of the hyperthermophile-specific protein, two subdomains af_H1 and af_H23 have been cloned into E. coli expression vector, pET28a. The $^{15}N$-labeled af_H1 and af_H23 proteins were expressed and purified for heteronuclear NMR study. The af_H1 protein exhibits the well-dispersion of amide signals in its $^1H/^{15}N$-HSQC spectra and thus further NMR study continues to be progressed.

• BMB Reports
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• v.53 no.2
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• pp.94-99
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• 2020

Brain cytoplasmic 200 RNA (BC200 RNA) is proposed to act as a local translational modulator by inhibiting translation after being targeted to neuronal dendrites. However, the mechanism by which BC200 RNA inhibits translation is not fully understood. Although a detailed functional analysis of RNA motifs is essential for understanding the BC200 RNA-mediated translation-inhibition mechanism, there is little relevant research on the subject. Here, we performed a systematic domain-dissection analysis of BC200 RNA to identify functional RNA motifs responsible for its translational-inhibition activity. Various RNA variants were assayed for their ability to inhibit translation of luciferase mRNA in vitro. We found that the 111-200-nucleotide region consisting of part of the Alu domain as well as the A/C-rich domain (consisting of both the A-rich and C-rich domains) is most effective for translation inhibition. Surprisingly, we also found that individual A-rich, A/C-rich, and Alu domains can enhance translation but at different levels for each domain, and that these enhancing effects manifest as cap-dependent translation.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1120-1126
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• 2013

The syndecan family consists of four transmembrane heparan sulfate proteoglycans present in most cell types and each syndecan shares a common structure containing a heparan sulfate modified extracellular domain, a single transmembrane domain and a C-terminal cytoplasmic domain. To get a better understanding of the mechanism and function of syndecan-4 which is one of the syndecan family, it is crucial to investigate its three-dimensional structure. Unfortunately, it is difficult to prepare the peptide because it is membrane-bound protein that transverses the lipid bilayer of the cell membrane. Here, we optimize the expression, purification, and characterization of transmembrane, cytoplasmic and short extracellular domains of syndecan4 (syndecan-4 eTC). Syndecan-4 eTC was successfully obtained with high purity and yield from the M9 medium. The structural information of syndecan-4 eTC was investigated by MALDI-TOF mass (MS) spectrometry, circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that syndecan-4 eTC had an ${\alpha}$-helical multimeric structure like transmembrane domain of syndecan-4 (syndecan-4 TM) in membrane environments.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.256-262
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• 2006

purpose of this study was to examine the effect of Small-Scale Chemistry(below SSC) Lab Program on academic achievement and science-related affective domain of high school students. For this study, SSC Lab Program was developed on the basis of analyzing the chemistry part of the high school science textbook in the 7th curriculum. The experimental group was received SSC experiment lessons(below SSC group), and the comparison group was received traditional lessons. According to the result of this study, there was a significant difference (p<.01) between a SSC group and a comparison group in academic achievement. Also, there were significant differences in science-related affective domain, especially interest and scientific attitude. It showed that SSC Lab Program was more effective to improve the academic achievement and science-related affective domain. Student perceptions on SSC Lab Program were also discussed. Majority of students thought that SSC lab program was an effective and interesting way in science study.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.17-17
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• 2003

tRNA (m¹ G37) methyltransferase (TrmD) catalyze s the trans for of a methyl group from S-adenosyl-L-methionine (AdoMet) to G/sup 37/ within a subset of bacterial tRNA species, which have a residue G at 36th position. The modified guanosine is adjacent to and 3' of the anticodon and is essential for the maintenance of the correct reading frame during translation. We have determined the first crystal structure of TrmD from Haemophilus influenzae, as a binary complex with either AdoMet or S-adenosyl-L-homocysteine (AdoHcy), as a ternary complex with AdoHcy/phosphate, and as an apo form. The structure indicates that TrmD functions as a dimer (Figure 1). It also suggests the binding mode of G/sup 36/G/sup 37/ in the active site of TrmD and catalytic mechanism. The N-terminal domain has a trefoil knot, in which AdoMet or AdoHcy is bound in a novel, bent conformation. The C-terminal domain shows a structural similarity to DNA binding domain of trp or tot repressor. We propose a plausible model for the TrmD₂-tRNA₂ complex, which provides insights into recognition of the general tRNA structure by TrmD (Figure 2).

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.67-71
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• 1996

The plasmid pK8 was constructed to verify the existence of an adenylate domain in peptide synthetase by using pGC12. 1.2 kb fragment, coding tyrocidine synthetase 1 (123 kDa) was deleted, and 79.6 kDa one was expressed in Escherichia coli XL1-blue. The truncated multienzyme activated phenylalanine and substrate analogues with comparable kinetics as the over expressed synthetase. ATP-[$^{32}P$]PPi exchange reaction was measured for the enzyme assay.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1353-1358
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• 2006

We investigated in vitro T-cell inhibitory activity and bioavailability of small chemical inhibitors for Lck SH2 domain, which had a different scaffold such as an amide bond, reduced amide bond, N-methyl amide bond, thioamide bond, and urethane bond. Each of these compounds, with its particular scaffold, showed a different logP value, stability against serum enzyme, stability in buffer solution, and in vitro T-cell inhibitory activity. Overall results indicated that the SH2 inhibitor containing urethane bond can be a new lead compound because of its superior bioavailability, potent in vitro T-cell inhibitory activity, and facile synthesis.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4201-4203
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• 2012