• 한국광물학회지
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• 제21권3호
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• pp.321-329
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• 2008

비정질 규산염 나노입자는 지각에 풍부한 규소와 산소로 이루어진 비다공성 나노입자로서 광물학을 포함한 지구환경과학과 산업적 측면에서 모두 중요한 물질이다. 본 연구에서는 $^{1}H$과 $^{29}Si$ MAS NMR분광분석을 통해 7 nm와 14 nm 규산염 나노입자의 규소와 수소 원자 환경을 측정하고, 입자 크기에 따른 규산염 나노입자 원자 환경 변화를 규명하였다. NMR 스펙트럼의 화학적 이동 값의 이론적 배경을 이해하기 위해 양자화학계간을 통해 $Si_{3}O_{6}H_6,\;Si_{4}O_{5}H_{10},\;Si_{5}O_{4}H_{12}$ 분자계간모델의 화학 차폐를 계산하였다. $^{29}Si$ MAS NMR의 결과, 이중 실라놀(geminal silanol)과 단일 실라놀(single silanol), 실록산(siloxane) 구조의 Si 원자 환경에 해당하는 $Q^2,\;Q^3,\;O^4$가 구분되어 나타나며 입자 크기에 따라 $Q^2,\;Q^3,\;O^4$가 7 nm규산염 나노입자에는 $7{\pm}1%,\;27{\pm}2%,\;66{\pm}2%$, 14 nm 규산염 나노입자에는 $6{\pm}1%,\;21{\pm}2%,\;73{\pm}2%$의 분포를 갖는다. $Q^2,\;Q^3$ 구조는 나노 입자의 표면적에 대부분 존재하는 것으로 예상되었으나, 두 규산염 나노입자의 표면적 차이에 비해 $Q^2,\;Q^3$ 양의 차이가 적으며, 이는 입자 표면 뿐 아니라 입자 내부에도 $Q^2,\;Q^3$ 구조가 존재함을 의미한다. $^{1}H$ MAS NMR 스펙트럼은 물리흡착 된 물(physisorbed water), 수소결합 된 수산기(hydrogen bended silanol), 비 수소결합 된 수산기(non-hydrogen bonded silanol)를 구분하여 나타낸다. 14 nm 비정질 규산염 나노입자에 비해 7nm 나노입자에 약 3.4 배의 수소 원자가 존재하며, 더 강한 수소결합 세기를 갖는다. 전체 수산기 중에서 비 수소결합 된 수산기가 차지하는 비율이 7 nm 규산염 나노입자 보다 14 nm 규산염 나노입자에서 더 높으며, 이는 수소 원자간의 상대적 거리(proximity)가 14 nm 임자에서 더 긴 것을 지시한다. 본 연구결과를 통하여 현재까지 알려지지 않은 규산염 나노입자의 입자의기에 의한 다양한 원자 구조의 변화를 규명하였다.

• 대한화학회지
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• 제36권5호
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• pp.685-691
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• 1992

디포스핀을 포함한 몇가지 $d^8$ 전이금속착물$(MCl_2PP)$은 출발물질 $K_nMCl_m$을 사용하여 합성하였다. 중심금속(M)은 Ni(II), Pd(II), Pt(II), Au(III)이며, 디포스핀(PP)은 bis(diphenylphosphino)methane(dppm), bis(diphenylphosphino)ethane(dppe), bis(diphenylphosphino)propane (dppp) 및 bis(diphenylphosphino)ethylene(dppety)이었다. 착물의 조성이나 특성은 원소분석과 $^1H-NMR$, $^{31}P-NMR$ 및 UV-Visible 스펙트럼을 이용하여 확인하였다. 이들 착물의 촉매적 활성은 3(2H)-furanone 및 cyclic carbonate 생성반응에 대하여 각각 조사하였다. 2-methyl-3-butyn-2-ol로부터 생성물 3(2H)-furanone을 얻은 반응 (1)에서 Ni(II)-, Pd(II)-diphosphine 착물은 좋은 촉매적 효과를 나타내었다. 그러나 이들 diphosphine 착물들은 cyclic carbonate 생성반응 (2)에 대해 촉매제로서의 활성을 거의 나타내지 않았다.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1467-1472
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• 2013

Metabolomics is a field that studies systematic dynamics and secretion of metabolites from cells to understand biological pathways based on metabolite changes. The metabolic profiling of intact human colorectal tissues was performed using high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, which was unnecessary to extract metabolites from tissues. We used two different groups of samples, which were defined as normal and cancer, from 9 patients with colorectal cancer and investigated the samples in NMR experiments with a water suppression pulse sequence. We applied target profiling and multivariative statistical analysis to the analyzed 1D NMR spectra to identify the metabolites and discriminate between normal and cancer tissues. Cancer tissue showed higher levels of arginine, betaine, glutamate, lysine, taurine and lower levels of glutamine, hypoxanthine, isoleucine, lactate, methionine, pyruvate, tyrosine relative to normal tissue. In the OPLS-DA (orthogonal partial least square discriminant analysis), the score plot showed good separation between the normal and cancer groups. These results suggest that metabolic profiling of colorectal cancer could provide new biomarkers.

• 농업과학연구
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• 제45권3호
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• pp.455-461
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• 2018

Deoxynivalenol (DON), a Fusarium mycotoxin, causes health hazards for both humans and livestock. Therefore, the aim of this study was to investigate the metabolic profiles of the liver, serum, and urine of piglets fed DON using proton nuclear magnetic resonance ($^1H-NMR$) spectroscopy. The $^1H-NMR$ spectra of the liver, serum, and urine samples of the piglets provided with feed containing 8 mg DON/kg for 4 weeks were aligned and identified using the icoshift algorithm of MATLAB $R^2013b$. The data were analyzed by multivariate analysis and by MetaboAnalyst 4.0. The DON-treated groups exhibited discriminating metabolites in the three different sample types. Metabolic profiling by $^1H-NMR$ spectroscopy revealed potential metabolites including lactate, glucose, taurine, alanine, glycine, glutamate, creatine, and glutamine upon mycotoxin exposure (variable importance in the projection, VIP > 1). Forty-six metabolites selected from the principal component analysis (PCA) helped to predict sixty-five pathways in the DON-treated piglets using metabolite sets containing at least two compounds. The DON treatment catalyzed the citrate synthase reactions which led to an increase in the acetate and a decrease in the glucose concentrations. Therefore, our findings suggest that glyceraldehyde-3-phosphate dehydrogenase, citrate synthase, ATP synthase, and pyruvate carboxylase should be considered important in piglets fed DON contaminated feed. Metabolomics analysis could be a powerful method for the discovery of novel indicators underlying mycotoxin treatments.

• 공업화학
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• 제4권3호
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• pp.505-514
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• 1993

올리고글리세롤 모노라우레이트 에스테르류를 단계적인 합성 방법으로 monoglycerol monolaurate, diglycerol monolaurate, symmetrical triglycerol monolaurate 및 symmetrical tetraglycerol monolaurate 등을 85~95%의 높은 수율로 각각 제조하였다. 그리고 이 화합물들에 대한 TLC 및 관크로마토그래피를 행하여 순수한 물질로 잘 분리 정제하였고, IR 및 $^1H\;NMR$로 구조를 확인하였다.

• Natural Product Sciences
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• 제6권2호
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• pp.91-95
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• 2000

A phytochemical investigation of the aqueous ethanolic flower extract of Tamarix tetragyna led to the isolation and characterization of the hitherto unknown conjugates, kaempheride 3,7-dipotassium sulphate and kaempferol 3,4'-dipotassium sulphate as well. Twelve known flavonol compounds, including kaempheride 3-potassium sulphate and kaempheride $3-O-{\beta}-glucuronide$ were also isolated and identified. $^1H-\;and\;^{13}C-NMR$ spectra for the known kaempheride derivatives have been recorded and assigned for the first time. Structures of all compounds were established by conventional methods of analysis and confirmed by $^1H-,\;^{13}C-NMR$ and mass spectral analysis.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.69-79
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• 2011

HP0827 has two RNP motif which is a very common protein domain involved in recognition of a wide range of ssRNA/DNA.We acquired 3D NMR spectra of HP0827 which shows well dispersed and homogeneous signals which allows us to assign 98% of all $^1H_N$, $^{15}N$, $^{13}C_{\alpha}$, $^{13}C_{\beta}$ and $^{13}C$=O resonances and 90% of all sidechain resonances. The sequence-specific backbone resonance assignment of HP0827 can be used to gain deeper insights into the nucleic acids binding specificity of HP0827 in the future study. Here, we report secondary structure prediction of HP0827 derived from NMR data. Additionally, ssRNA/DNA binding assay studies was also conducted. This study might provide a clue for exact function of HP0827 based on structure and sequence.

• 한국자기공명학회논문지
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• 제16권2호
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• pp.172-184
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• 2012

The prokaryotic molecular chaperone Hsp33 achieves its holdase activity upon response to oxidative stress particularly at elevated temperature. Despite many structural studies of Hsp33, which were conducted mainly by X-ray crystallography, the actual structures of the Hsp33 in solution remains controversial. Thus, we have initiated NMR study of the reduced, inactive Hsp33 monomer and backbone NMR assignments were obtained in the present study. Based on a series of triple resonance spectra measured on a triply isotope-[$^2H/^{13}C/^{15}N$]-labeled protein, sequence-specific assignments of the backbone amide signals observed in the 2D-[$^1H/^{15}N$]TROSY spectrum could be completed up to more than 96%. However, even considering the small portion of non-assigned resonances due to the lack of sequential connectivity, we confirmed that the total number of observed signals was quite smaller than that expected from the number of amino acid residues in Hsp33. Thus, it is postulated that peculiar dynamic properties would be involved in the solution structure of the inactive Hsp33 monomer. We expect that the present assignment data would eventually provide the most fundamental and important data for the progressing studies on the 3-dimensional structure and molecular dynamics of Hsp33, which are critical for understanding its activation process.

• 한국자기공명학회논문지
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• 제16권2호
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• pp.162-171
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• 2012

SAV2228 has an OB (Oligomer-Binding)-motif which is frequently used for nucleic acid recognition. To characterize the activity of translation initiation factor-1 (IF-1) from Staphylococcus aureus, SAV2228 was expressed and purified in Escherichia coli. We acquired 3D NMR spectra showing well dispersed and homogeneous signals which allow us to assign 94.4% of all $^1HN$, $^{15}N$, $^{13}C{\alpha}$, $^{13}C{\beta}$ and $^{13}CO$ resonances. We could predict a secondary structure of SAV2228 using TALOS and CSI from NMR data. SAV2228 was consisted of one ${\alpha}$-helix and five ${\beta}$-sheets. The predicted secondary structure, ${\beta}-{\beta}-{\beta}-{\alpha}-{\beta}-{\beta}$, was similar to other bacterial IF-1, but it was not completely same to the eukaryotic one. Assigned NMR peaks and secondary structre prediction can be used for the study on interaction with nucleic acid in the future.

• Journal of Ginseng Research
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• 제40권3호
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• pp.245-250
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• 2016

Background: Ginsenosides are the major effective ingredients responsible for the pharmacological effects of ginseng. Malonyl ginsenosides are natural ginsenosides that contain a malonyl group attached to a glucose unit of the corresponding neutral ginsenosides. Methods: Medium-pressure liquid chromatography and semipreparative high-performance liquid chromatography were used to isolate purified compounds and their structures determined by extensive one-dimensional- and two-dimensional nuclear magnetic resonance (NMR) experiments. Results: A new saponin, namely malonyl-ginsenoside Re, was isolated from the fresh flower buds of Panax ginseng, along with malonyl-ginsenosides Rb1, Rb2, Rc, Rd. Some assignments for previously published $^1H$- and $^{13}C$-NMR spectra were found to be inaccurate. Conclusion: This study reports the complete NMR assignment of malonyl-ginsenoside Re, $Rb_1$, $Rb_2$, Rc, and Rd for the first time.