• Title/Summary/Keyword: }NMR$

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Purification and Backbone Assignment of the Hypothetical Protein MTH1821 from Methanobacterium Thermoautotrophicum H

  • Kwak, Soo-Young;Lee, Woong-Hee;Shin, Joon;Ko, Sung-Geon;Lee, Weon-Tae
    • Journal of the Korean Magnetic Resonance Society
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    • v.11 no.2
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    • pp.73-84
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    • 2007
  • MTH1821 (UniProtKB/TrEMBL ID O27849) is a 96-residue hypothetical protein from the open reading frame of Methanobacterium thermoautotrophicum H one of the target organisms of structural genomics pilot project. Proteins which contain conserved sequence compared with MTH1821 have not been discovered yet and the functional and structural information for MTH1821 is not available. Here, we present the sequence-specific backbone resonance using multidimensional heteronuc1ear NMR spectroscopy and propose the secondary structure using GetSBY software. The backbone resonances of N, HN, $C_{\alpha}$, $C_{\beta}$, CO and $H_{\alpha}$ which are necessary for a prediction of secondary structure by GetSBY were assigned about 98% (557/568). The secondary structure of MTH1821 confirmed that it is comprised of four strand regions and two helical regions. This report will provide a valuable resource for the calculation solution structure of MTH1821 and for the other hypothetical protein that is targeted for structural-based functional discovery.

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Phenolic Compounds from Acer tegmentosum Bark (산겨릅나무 수피의 페놀성 화합물)

  • Kwon, Dong-Joo;Bae, Young-Soo
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.6
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    • pp.145-151
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    • 2007
  • To investigate the chemical constituents of Acer tegmentosum, the bark were collected, air-dried and extracted with 70% aqueous acetone. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography on the EtOAc soluble fraction gave five phenolic compounds. Their structures were elucidated as (+)-catechin (1), (-)-epi-catechin (2), Q-epicatechin-3-O-gallate (3), gallic acid (4) and 6'-0-galloylsalidroside (5) on the basis of spectroscopic evidences using $^1H-NMR$, $^{13}C-NMR$, 2D-NMR and MS spectroscopy, (-)-epicatechin-3-Ogallate (3), gallic acid (4), 6'-Ogalloylsalidroside (5) have not been reported in this plant yet.

Microstructure and Thermal Characteristics of Bio-based Terpolymer Made from Terephthalic Acid with Ethylene Glycol, 1,4-Cyclohexane Dimethanol, and Isosorbide (Ethylene Glycol, 1,4-Cyclohexane Dimethanol, Isosorbide와 Terephthalic Acid로 제조되는 바이오기반 삼원공중합체의 미세구조 및 열적 특성)

  • Lee, Sangmook;Kim, Sungki;Hong, In-Kwon
    • Polymer(Korea)
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    • v.39 no.2
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    • pp.287-292
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    • 2015
  • Characterization of a series of bio-based terpolymers containing various amounts of ethylene glycol, 1,4-cyclohexylene dimethanol, and isosorbide units were studied by $^1H$ NMR and $^{13}C$ NMR. The NMR results revealed that they had all random microstructures and that their sequence distribution was affected by the content of isosorbide. From DSC data for the terpolymer series investigated, it was observed that the glass transition temperature increased mainly as the content of isosorbide increased. The glass transition temperatures of terpolymers were estimated from the composition by extended Fox equation.

Cloning, Purification, and Structural Characterization by 1D 1H-NMR of the PDZ domain of the Shank3 protein (Shank3 PDZ 도메인의 동정, 정제 및 1차 NMR 구조분석)

  • Sung, Mee-Sook
    • Journal of Life Science
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    • v.17 no.3 s.83
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    • pp.345-349
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    • 2007
  • We wished to create a set of small molecular weight PDZ domain ligands that may be used in functional studies on the proteins AF6, PSD-95 and Shank. As a starting point, the Shank3 PDZ domain was cloned, purified, and characterized the structure of Shank3 PDZ domain by 1D $^1H-NMR$. The chemical shift dispersion of the proton signals indicates that the purified Shank3 PDZ protein is very pure and globally well folded. Currently, we are working on improving the yield of the protein production for complete NMR structural analysis of the Shank3 PDZ domain.

NMR Chemical Shift for 4d$^n$System (Ⅳ). Calculation of NMR Chemical Shift for 4d$^2$ System in a Strong Crystal Field Environment of Octahedral Symmetry

  • Ahn, Sang-Woon;Oh, Se-Woong;Yang, Jae-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.6 no.5
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    • pp.255-259
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    • 1985
  • The NMR chemical shift arising from 4d electron orbital angular momentum and 4d electron spin dipolar-nuclear Spin angular momentum interactions for a $4d^2$ system in a strong crystal field environment of octahedral symmetry has been investigated when the four fold axis is taken as the quantization axis. The NMR results are comparted with the multipolar shift at various R-values and we find that the exact results are in agreement with the multipolar shift when $R{\geqslant}0.20 nm.$ We also separate the NMR shift into the contribution of the $1/R^5$ and $1/R^7$ terms. It is found that the contribution of the $1/R^5$term to the NMR shift is dominant than the contribution of the $1/R^7$ term. Temperature dependence analysis shows that the $1/T^2$ term is the dominant contribution to the NMR shift for a $4d^2$ system but the contribution of the 1/T term may not negligible. The similar results are obtained for a $4d^1$ system from the temperature dependence analysis.

Refinement of protein NMR structures using atomistic force field and implicit solvent model: Comparison of the accuracies of NMR structures with Rosetta refinement

  • Jee, Jun-Goo
    • Journal of the Korean Magnetic Resonance Society
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    • v.26 no.1
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    • pp.1-9
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    • 2022
  • There are two distinct approaches to improving the quality of protein NMR structures during refinement: all-atom force fields and accumulated knowledge-assisted methods that include Rosetta. Mao et al. reported that, for 40 proteins, Rosetta increased the accuracies of their NMR-determined structures with respect to the X-ray crystal structures (Mao et al., J. Am. Chem. Soc. 136, 1893 (2014)). In this study, we calculated 32 structures of those studied by Mao et al. using all-atom force field and implicit solvent model, and we compared the results with those obtained from Rosetta. For a single protein, using only the experimental NOE-derived distances and backbone torsion angle restraints, 20 of the lowest energy structures were extracted as an ensemble from 100 generated structures. Restrained simulated annealing by molecular dynamics simulation searched conformational spaces with a total time step of 1-ns. The use of GPU-accelerated AMBER code allowed the calculations to be completed in hours using a single GPU computer-even for proteins larger than 20 kDa. Remarkably, statistical analyses indicated that the structures determined in this way showed overall higher accuracies to their X-ray structures compared to those refined by Rosetta (p-value < 0.01). Our data demonstrate the capability of sophisticated atomistic force fields in refining NMR structures, particularly when they are coupled with the latest GPU-based calculations. The straightforwardness of the protocol allows its use to be extended to all NMR structures.

7Li MAS NMR studies of Li4P2O7 and LiFePO4 materials (LiFePO4와 Li4P2O77Li MAS NMR 특성 연구)

  • Han, Doug-Young;Park, Nam-Sin;Lee, Sang-Hyuk;Lee, Hak-Man;Kim, Chang-Sam
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.1
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    • pp.15-20
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    • 2011
  • [ $^7Li$ ]Magic Angle Spinning (MAS) NMR spectroscopy has been used to study the lithium local environments in $Li_4P_2O_7$ and$LiFePO_4$ materials. The purpose of this study was to know the structure of the solid electrolyte interphase (SEI) in lithium ion cells composed of $LiFePO_4$ as cathode material. $Li_4P_2O_7$ and $LiFePO_4$ were prepared by a solid-state reaction. The $^7Li$ MAS NMR experiments were carried out at variable temperatures in order to observe the local structure changes at the temperatures in $Li_4P_2O_7$ system. The $^7Li$ MAS NMR spectra of in $Li_4P_2O_7$ indicate that the lithium local environments in $Li_4P_2O_7$ were not changed in the temperature range between $27^{\circ}C$ and $97^{\circ}C$ Through this work, we confirmed that the small amount of $Li_4P_2O_7$ less than 5.0 wt% in $LiFePO_4$ could be clearly measured by the $^7Li$ MAS NMR spectroscopy at high spinning rate over than 11 kHz.

NMR/MRI Superconducting Magnet Technologies: Recent Activities at MIT Francis Bitter Magnet Laboratory

  • Yukikazu Iwasa;Lee, Haigun
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.1
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    • pp.1-12
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    • 2003
  • In this paper we present a brief description and summary results of each of our recent activities in three areas, all devoted to NMR and MRI superconducting magnet technologies: 1) development of a high-field LTS / HTS NMR magnet; 2) development of a novel digital flux injector for slightly resistive NMR magnets; and 3) a proposal fer a low-cost MRI magnet system based on $MgB_2$ composite and an innovative cryogenic design / operation concept.

Spectroscopic Studies of Gas Hydrates (가스 하이드레이트의 분광학적 연구)

  • Kim, Do-Youn;Lee, Heun;Seo, Yu-taek
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.615-617
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    • 2005
  • [ $^{13}C$ ] NMR spectra were obtained for pure $CH_4$ hydrate in order to identify hydrate structure and cage occupancy of guest molecule. The NMR technique can provide both qualitative and quantitative hydrate characteristics. The moles of methane captured into pure $CH_4$ hydrate per mole of water were found to be similar to the full occupancy value. The overall results drawn from this study can be usefully applied to storage and transportation of natural gas.

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