• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.510-514
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• 2011

Based on first-principles LCAO method, we study the electronic and atomic structures of DNA nucleobases adenine (A), thymine (T), guanine (G), and cytosine (C) adsorbed on graphene surfaces. The ${\pi}-{\pi}$ stacking interactions between graphene and nucleobases lead to the bilayer geometries similar to the Bernal stacked graphite. Through the density of states and charge density analyses, it is found that nucleobases are physisorbed on graphene by dispersive interactions with negligible charge exchange. Our calculations reproduce the atomic structures obtained in previous plane wave calculations accurately with much less computation, and well describe the delocalized ${\pi}-{\pi}$ interactions in graphene-nucleobases system, indicating that the LCAO method is very efficient for investigating graphene-bio systems.

• 한국식품영양과학회지
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• 제12권1호
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• pp.1-6
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• 1983

인삼(人蔘)과 오가피중(五加皮中)의 핵산계(核酸系) 성분(成分)을 HPLC로 분리(分離) 정량(定量)하여 다음과 같은 결과를 얻었다. 1. 동일한 원료수삼에서 제조한 백삼(白蔘)과 홍삼(紅蔘)의 핵산유리염기(核酸遊離鹽基)와 nucleoside의 조성이 거의 같았다. 2. 인삼(人蔘)과 오가피(五加皮)중의 nucleosides 함량에서 adenosine, guanosine, cytidine 등이 특징적(特徵的)인 차이(差異)를 나타냈으며 인삼속(人蔘屬)이 약(約) 3배(倍)이상 많게 나타났다. 그러나 tymidine과 inosine은 오가피속(五加皮屬)이 다소 많았다. 3. nucleobase 함량면에서는 인삼(人蔘)이나 오가피간(五加皮間)에 비슷한 함량으로 1~2mg/100g를 함유했다.

• Asian-Australasian Journal of Animal Sciences
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• 제4권2호
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• pp.161-164
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• 1991

A rapid and accurate method is described for the determination of nucleo-bases in rumen micro-organisms. A procedure to satisfactorily hydrolyse the micro-organisms involving reaction with a mixture of readily volatile organic acids (acetic and formic acids) under high pressure, is proposed, and optimal conditions for an analytical procedure with reversed phase HPLC is described. The following nucleobases contents (mmol/kg DM) of rumen micro-organisms were found: Adenine (Ade), 82.62; Guanine (Gua), 61.34; Cytosine (Cyt), 84.61; Thymine (Thy), 35.74; Uracil (Ura), 68.62; Hypoxanthine (Hxn), 13.06; Xanthine (Xn), 8.35. Total purine-N content (g/kg N) of rumen micro-organisms were 99.60. The nucleic acid N content (g/kg N) of microbial isolates were: RNA-N, 109.9; DNA-N, 50.9.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3794-3796
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• 2010

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.2906-2910
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• 2011

A fluorescent nucleoside analogue, $^AC$, featuring two non-complementary nucleobases linked through an ethynyl group, was synthesized. The extended ${\pi}$-conjugation imparts $^AC$ with red-shifted absorbance (relative to adenine and cytosine) and pale-blue fluorescence. It spontaneously forms nanoparticles, which exhibit considerably enhanced fluorescence, without the help of any additional stabilizing agent. The DMSO/water ratio was an important factor influencing the construction of the NPs. X-ray crystallography confirmed the structure of $^AC$; dynamic light scattering and scanning electron microscopy confirmed the existence of the nanoparticles.

• 분석과학
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• 제8권3호
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• pp.313-319
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• 1995

표면강화 라만분광학을 이용하여 단일전자 산화반응으로 형성된 발암성 벤조피렌 유도체가 nucleobase와 반응하여 생성된 첨가 생성물을 분석하였다. 표면강화 라만분광학을 이용하여 아데닌 또는 구아닌과 같이 각기 다른 종류의 nucleobase와 결합하여 형성된 첨가생성물을 구분하여 분석할 수 있었고 또한 nucleobase 분자의 다른 부분에 결합하여 형성된 이성길체를 라만분광스펙트럼을 통하여 구분하여 분석이 가능하였다. N7Ade-BP에 대한 검정곡선의 선형도 범위는 20 picogram/${\mu}l$에서 800 nanogram/${\mu}l$였고, 본 실험 조건하에서의 검출한계는 $20{\mu}l$의 샘플을 이용하고 20 picogram/${\mu}l$였다.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3658-3662
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• 2010

A new bis-Ru(II) complex, in which two [Ru(1,10-phenanthroline)$_2$dipyrido[3,2-a:2',3'-c]phenazine]$^{2+}$ were tethered by a 1,3-bis(4-pyridyl)propane linker, was synthesized and its binding mode and stoichiometry to DNA was investigated by optical spectroscopy including linear dichroism (LD) and fluorescence intensity measurement. The magnitude of the negatively reduced LD signal of the bis-Ru(II) complex in the dipyrido[3,2-a:2',3'-c]phenazine (DPPZ) ligand absorption region appeared to be similar compared to that in the DNA absorption region, which is considered to be a diagnostic for DPPZ ligand intercalation. The binding stoichiometry measured from its LD magnitude and enhanced fluorescence intensity corresponds to one ligand per three DNA bases, effectively violating the nearest neighbouring site exclusion model for classical DNA intercalation. This observation is in contrast with monomer analogue [Ru(1,10-phenanthroline)$_2$dipyrido[3,2-a:2',3'-c]phenazine]$^{2+}$, which is saturated at the DPPZ ligand to DNA base ratio of 0.25, or one DPPZ ligand per four nucleobases.

• 대한화학회지
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• 제34권4호
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• pp.331-339
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• 1990

cis-diamminedichloroplatinum (II)에서 아민리간드가 변화할 때, 항암성과 백금원자의 전자구조 사이의 관계를 연구하였고, 또 이러한 착물과 DNA base인 1-methylcytosine의 상호작용에 대한 메카니즘을 알기 위해서 백금(II)착물들을 분자궤도함수론적으로 연구하였다. 그 결과, 백금착물에서 중심금속의 atomic charge가 항암성에 영향을 미치고 있음을 알았다. 또한 백금착물과 1-methylcytosine의 결합은 리간드에서 금속원자로 전하이동을 하였고, 이 때 Pt(II)의 6p-orbital이 중요한 하고 있음을 발견한다. Pt-N3결합성은 $\alpha$ 와 $\pi$ 성분을 포함하고 있으며, 실험한 값과 비교할 때 비교할 때 항암성이 큰 백금착물일수록 Pt-N3 결합이 강하게 형성하고 있었다.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1519-1526
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• 2010

The behavior of peptide or protein solutes in saline aqueous solution is a fundamental topic in physical chemistry. Addition of ions can strongly alter the thermodynamic and physical properties of peptide molecules in solution. In order to study the effects of added ionic salts on protein conformation and dynamics, we have used the molecular dynamics (MD) simulations to investigate the behavior of Staphylococcus aureus Hfq protein under two different ionic concentrations: 0.1 M NaCl and 1.0 M NaCl in presence and absence of RNA (a hepta-oligoribonucleotide AU5G). Hfq, a global regulator of gene expression is highly conserved and abundant RNA-binding protein. It is already reported that in vivo the increase of ionic strength results in a drastic reduction of Hfq affinity for $Q{\beta}$ RNA and reduces the tendency of aggregation of Escherichia coli host factor hexamers. Our results revealed the crucial role of 0.1 M NaCl Hfq system on the bases with strong hydrogen bonding interactions and by stabilizing the aromatic stacking of Tyr42 residue of the adjacent subunits/monomers with the adenine and uridine nucleobases. An increase in RNA pore diameter and weakened compactness of the Hfq-RNA complex was clearly observed in 1.0 M NaCl Hfq system with bound RNA. Aggregation of monomers in Hfq and the interaction of Hfq with RNA are greatly affected due to the presence of high ionic strength. Higher the ionic concentration, weaker is the aggregation and interaction. Our results were compatible with the experimental data and this is the first theoretical report for the experimental study done in 1980 by Uhlenbeck group for the present system.