• Applied Biological Chemistry
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• 제41권8호
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• pp.572-577
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• 1998

The solution conformation of the human insulin precursor, preproinsulin, is described in terms of NMR spectral data. NMR experiments were performed on preproinsulin, whose structure was compared with the NMR structure of native human insulin. Despite the presence of the C-peptide and/or the signal peptide, secondary structure analyses indicate that the native structures of the A and B chains are well conserved even in preproinsulin. The observed relative robustness of the native structure in precursor forms permits further protein engineering experiments where the C-peptide or N-terminal signal sequence can be altered for the purpose of increasing expression or purification yields when producing recombinant human insulin.

• 생약학회지
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• 제12권1호
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• pp.12-14
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• 1981

${\beta}-Sitosteryl-3-O-{\beta}-D-glucopyranoside$ was isolated from the seeds of Plantago asiatica (Plantaginaceae). The assignments of $^{13}C$ NMR spectra of ${\beta}-sitosterol$ and ${\beta}-sitosteryl-3-O-{\beta}-D-glucopyranoside$ were made by comparing with $^{13}C$ NMR spectra of cholesterol and $cholesteryl-3-O-{\beta}-D-glucopyranoside$. Our data indicate that the revision of previous $^{13}C$ NMR spectral assignment is needed.

• 분석과학
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• 제14권1호
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• pp.1-7
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• 2001

6,6-Dichlorobicyclo[3, 1, 0]hexane-3carboxylic acid를 phase transfer catalyst(PTC)로 benzyl triethylamine chloride(BTEA.Cl)를 사용하여 3-cyclopentenecarboxylic acid로부터 합성하였다. $^1H$ NMR과 $^{13}C$ NMR 분석을 통하여 이 화합물은 boat-like conformation을 갖는 것으로 나타났고 carboxyl group은 trans로 존재하는 것으로 나타났다.

• 한국자기공명학회논문지
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• 제17권1호
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• pp.1-10
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• 2013

Metabolomics is the study which detects the changes of metabolites level. Metabolomics is a terminal view of the biological system. The end products of the metabolism, metabolites, reflect the responses to external environment. Therefore metabolomics gives the additional information about understanding the metabolic pathways. These metabolites can be used as biomarkers that indicate the disease or external stresses such as exposure to toxicant. Many kinds of biological samples are used in metabolomics, for example, cell, tissue, and bio fluids. NMR spectroscopy is one of the tools of metabolomics. NMR data are analyzed by multivariate statistical analysis and target profiling technique. Recently, NMR-based metabolomics is a growing field in various studies such as disease diagnosis, forensic science, and toxicity assessment.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1139-1142
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• 2009

Refinement of NMR structures by molecular dynamics (MD) simulations with a solvent model has improved the structural quality. In this study, we applied MD refinement with the generalized Born (GB) implicit solvent model to protein structure determined under membrane-like environments. Despite popularity of the GB model, its applications to the refinement of NMR structures of hydrophobic proteins, in which detergents or organic solvents enclose proteins, are limited, and there is little information on the use of another GB parameter for these cases. We carried out MD refinement of crambin NMR structure in dodecylphosphocholine (DPC) micelles (Ahn et al., J. Am. Chem. Soc. 2006, 128, 4398-4404) with GB/Surface area model and two different surface tension coefficients, one for aquatic and the other for hydrophobic conditions. Our data show that, of two structures by MD refinement with GB model, the one refined with the parameter to consider hydrophobic condition had the better qualities in terms of precision and solvent accessibility.

• 한국자기공명학회논문지
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• 제18권2호
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• pp.82-88
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• 2014

Three bicyclic and one monocyclic sesquiterpenoids were isolated from the marine sponge Topsentia species. Their planar structures were completely determined from a combination of extensive 1D and 2D NMR experiments, and also the relative stereochemistry on the chiral centers were established by the ROESY experiment. Compound 1 was determined as a new stereoisomer. Furthermore, the NMR spectral data for compounds 2 and 4, of which have not been reported, were listed. Four compounds did not show any cytotoxicity, instead compound 4 exhibited moderate antifungal activity against Candida albicans.

• Bulletin of the Korean Chemical Society
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• 제15권1호
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• pp.12-14
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• 1994

p-Fluorophenyl bicyclo[3.2.l]oct-6-en-2-yl cation (3) prepared in $FSO_3H-SO_2-CIF$ solution at -90$^{\circ}$C and examined by fluorine-19 nmr spectroscopy. The nmr data give a clear evidence for the formation of a stabilized ${\pi}$-bridging cation species in superacids. The degree of ${\pi}$delocalization in this cation is found to be inferior to the onset of nonclassical stabilization in 2-norbornenyl cation.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.198-202
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• 2004

Hydrogen bond is an important factor in the structures of carbohydrates. Because of great strength, short range, and strong angular dependence, hydrogen bonding is an important factor stabilizing the structure of carbohydrate. In this study, conformational properties and the hydrogen bonds in GlcNAc( ${\beta}$1,3)Gal(${\beta}$)OMe in DMSO are investigated through NMR spectroscopy and molecular dynamics simulation. Lowest energy structure in the adiabatic energy map was utilized as an initial structure for the molecular dynamics simulations in DMSO. NOEs, temperature coefficients, SIMPLE NMR data, and molecular dynamics simulations proved that there is a strong intramolecular hydrogen bond between O7' and HO3' in GlcNAc( ${\beta}$1,3)Gal(${\beta}$)OMe in DMSO. In aqueous solution, water molecule makes intermolecular hydrogen bonds with the disaccharides and there was no intramolecular hydrogen bonds in water. Since DMSO molecule is too big to be inserted deep into GlcNAc(${\beta}$1,3)Gal(${\beta}$)OMe, DMSO can not make strong intermolecular hydrogen bonding with carbohydrate and increases the ability of O7' in GlcNAc(${\beta}$1,3)Gal(${\beta}$)OMe to participate in intramolecular hydrogen bonding. Molecular dynamics simulation in conjunction with NMR experiments proves to be efficient way to investigate the intramolecular hydrogen bonding existed in carbohydrate.

• 공업화학
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• 제10권4호
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• pp.628-634
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• 1999

유기첨가제인 ${\omega}$-phenylalkylammonium 염이 sodium dodecyl sulfate(SDS)의 미셀계면에 결합되는 배향과 미셀속으로 유기염이 침투되는 정도를 $^{1}H\;NMR$ 자료를 이용하여 연구하였다. SDS의 메틸렌 양성자들의 높은장 쪽으로의 화학이동 값의 변화는 유기염의 농도에따라 선형적으로 변하게 되는데 이것은 유기염이 미셀내에 삽입되는 증거이다. 유기염의 알킬기의 길이가 길어질수록 벤젠고리의 양성자들과 계면활성제의 메틸렌 양성자들은 공명 신호들이 더욱 높은장 쪽으로 이동됨을 보여주었다. 유기염들은 알킬암모늄기를 미셀의 계면 밖으로 배향하며 벤젠고리는 미셀의 중심을 향하여 palisade 층까지 침투한다고 생각된다. 유기 첨가제는 알킬기의 길이가 길어질수록 SDS 미셀의 palisade 층으로 더욱 깊이 침투하여 혼합미셀를 형성한다고 생각한다.

• Journal of Ginseng Research
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• 제38권3호
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• pp.194-202
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• 2014

Background: Ginsenosides, the major ingredients of Panax ginseng, have been studied for many decades in Asian countries as a result of their wide range of pharmacological properties. The less polar ginsenosides, with one or two sugar residues, are not present in nature and are produced during manufacturing processes by methods such as heating, steaming, acid hydrolysis, and enzyme reactions. $^1H$-NMR and $^{13}C$-NMR spectroscopic data for the identification of the less polar ginsenosides are often unavailable or incomplete. Methods: We isolated 21 compounds, including 10 pairs of 20(S) and 20(R) less polar ginsenosides (1-20), and an oleanane-type triterpene (21) from a processed ginseng preparation and obtained complete $^1H$-NMR and $^{13}C$-NMR spectroscopic data for the following compounds, referred to as compounds 1-21 for rapid identification: 20(S)-ginsenosides Rh2 (1), 20(R)-Rh2 (2), 20(S)-Rg3 (3), 20(R)-Rg3 (4), 6'-O-acetyl-20(S)-Rh2 [20(S)-AcetylRh2] (5), 20(R)-AcetylRh2 (6), 25-hydroxy-20(S)-Rh2 (7), 25-hydroxy-20(S)-Rh2 (8), 20(S)-Rh1 (9), 20(R)-Rh1 (10), 20(S)-Rg2 (11), 20(R)-Rg2 (12), 25-hydroxy-20(S)-Rh1 (13), 25-hydroxy-20(R)-Rh1 (14), 20(S)-AcetylRg2 (15), 20(R)-AcetylRg2 (16), Rh4 (17), Rg5 (18), Rk1 (19), 25-hydroxy-Rh4 (20), and oleanolic acid 28-O-b-D-glucopyranoside (21).