• Corrosion Science and Technology
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• 제7권6호
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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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• 제33권1호
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• pp.281-284
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• 2012

• 한국자기공명학회논문지
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• 제19권2호
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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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• 제53권2호
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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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• 제34권4호
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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.

• 대한화학회지
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• 제50권3호
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• pp.256-262
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• 2006

연구의 목적은 Small-Scale Chemistry(SSC)를 적용한 수업이 고등학생의 과학성취도 및 과학관련 정의적 특성에 미치는 효과를 알아보는 것이다. 이를 위해 제 7차 교육과정의 고등학교 과학 교과서 화학영역에 대한 SSC 실험 프로그램을 개발하였다. 실험집단에는 SSC 실험 프로그램을 적용하고 비교 집단에서는 교과서를 중심으로 한 전통적 실험 수업을 실시하여 사전-사후 과학성취도 및 과학관련 정의적 영역의 변화를 조사하였다. 연구결과에 의하면 SSC 실험 프로그램을 적용하여 수업한 실험집단의 성취도가 교과서 내용의 전통적인 실험수업을 실시한 비교집단에 비해 유의미하게 높았다(p<.01). 과학관련 정의적 영역의 경우, 흥미와 과학적 태도 영역에서도 SSC 실험집단이 비교집단에 비해 유의미하게 높은 것으로 나타났다(p<.05). 또한 SSC 적용 수업에 대한 학생들의 인식을 살펴본 결과 학생들은 대부분 과학학습에 있어 효과적이고 흥미 있는 수업이라고 응답하였으며, 과학성취도와 정의적 영역의 변화를 잘 설명해주고 있었다.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2003년도 춘계학술연구발표회
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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).

• 한국미생물·생명공학회지
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• 제24권1호
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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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• 제27권9호
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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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• 제33권12호
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• pp.4201-4203
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• 2012