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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Magnetic Resonance Society
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Korean Magnetic Resonance Society
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Volume 8, Issue 2 - Dec 2004
Volume 8, Issue 1 - Jun 2004
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Decreased entropy of unfolding increases the temperature of maximum stability: Thermodynamic stability of a thioredoxin from the hyperthermophilic archaeon Methanococcus jannaschii
Lee, Duck-Yeon ; Kim, Kyeong-Ae ; Kim, Key-Sun ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 1~18
A thioredoxin from hyperthermophile, Methanococcus jannashii (MjTRX) was characterized by use of the differential scanning calorimetry to understand the mechanisms of thermodynamic stability. MjTRX has an unfolding transition temperature of 116.5
, although the maximum free energy of the unfolding (9.9 Kcal/mol) is similar to that of E. coli thioredoxin (ETRX, 9.0 Kcal/mol). However, the temperature of maximum stability is higher than ETRX by 20
, indicating that the unfolding transition temperature increased by shifting the temperature of maximum stability. MjTRX has lower enthalpy and entropy of the unfolding compared to ETRX maintaining a similar free energy of the unfolding. From the structure and the thermodynamic parameters of MjTRX, we showed that the unfolding transition temperature of MjTRX is increased due to the decreased entropy of the unfolding. Decreasing the unfolded state entropy and increasing the folded state entropy can decrease the entropy of the unfolding. In the case of MjTRX, the increased number of proline residues decreased the unfolded state entropy and the increased enthalpy in the folded state increased the folded state entropy.
Structure of CT16 in the C-terminal of Amyloid Precursor Protein Studied by NMR Spectroscopy
Lee, Kyoung-Ik ; Baek, Dong-Ha ; Shin, Song-Yub ; Kim, Yang-Mee ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 19~27
C-terminal fragments of APP (APP-CTs), that contain complete Abeta sequence, are found in neuritic plaques, neurofibrillary tangles and the cytosol of lymphoblastoid cells obtained from AD patients. CT16, Lys649-Asp664 (KKQYTSIHHGVVEVD) has been known as the most toxic part in the C-terminal fragment of amyloid precursor protein (APP). The solution structure of CT16 was investigated using NMR spectroscopy in various membrane-mimicking environments. According to Circular Dichroim (CD) spectra, CT16 has a random structure in aqueous solution, while conformational change was induced by addition of TFE and SDS micelle. Tertiary structure as determined by NMR spectroscopy shows that CT16 has a
-turn conformation in trifluoroethanol-containing aqueous solution.
Metabolic Abnormalities in Idiopathic Parkinson's Diseases with Unilateral Symptoms
Choe, Bo-Young ; Kim, Moon-Chan ; Kim, Bum-Soo ; Lee, Jae-Moon ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 28~36
Authors investigated whether there is a lateral effect of
H MRS observable metabolite ratios between the symptomatic and the nonsymptomatic side in the early stage of Parkinson's disease with unilateral symptom. Localized in vivo
H MR spectroscopy (MRS) was used to measure the metabolite levels in the symptomatic and the nonsymptomatic sides of the lentiform nucleus in Parkinson"s disease with unilateral symptom (N=25). The metabolite ratios of NAA/Cr and Cho/Cr in the symptomatic side were compared with those in the nonsymptomatic side. Significant metabolic lateral effect of NAA/(Cho+Cr) ratio was established between the symptomatic and the nonsymptomatic side of lentiform nucleus in Parkinson's disease with unilateral symptom (p<0.05). The ratio of NAA/(Cho+Cr) homolateral to the sympatomatic side of the patient is also lower than that of the control (P<0.05). On the basis of NAA/Cr ratios of lentiform nucleus between the symptomatic and the nonsymptomatic side, the present
H MRS study shows a significant neuronal laterality in Parkinson's disease with unilateral symptom. In vivo
H MRS may provide a diagnostic marker for neuronal dysfunction in Parkinson's disease with unilateral symptom.
ESR Study on the Thermal Annealing Effects of Irradiated Human Tooth Enamel by X and
Heo, Kyong-Chan ; Ok, Chi-Il ; Moon, Soo-Gil ; Na, Sung-Ho ; Kim, Jang-Whan ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 37~46
When human tooth enamel is exposed to the X-ray or
-rays, free radicals and defects are created in a small quantity of carbonate enclosed in the tooth enamel. The intensity of the ESR signal of the free radicals is almost proportional to the absorbed radiation dose. However this dosimetric character is affected to some extent with the measurement temperature and thermal treatment of the samples. We found that the shape of the ESR signals of the samples is dependent upon the measurement temperature, the thermal annealing prior to the irradiation and that after the irradiation.
EPR Lineshape and g-Factor of the Single Crystal
Son, Phil-Kook ; Hwang, Young-Hun ; Heo, Kyong-Chan ; Kim, Hung-Cheol ; Ok, Chi-Il ; Um, Young-Ho ; Kim, Jang-Whan ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 47~54
We have measured the linewidth and g-factor of EPR signals of the single crystal Mn
as a function of Mn-composition (0.4
0.9). We have investigated the linewidth of Mn
as a function of temperature (100
300 K). From these results EPR linewidth equation could be fitted for experimental data of EPR linewidth. This type of equation is similar to the shape of EPR linewidth of DMS (dulite magnetic semiconductor).or).r).
NMR Probe Development for Investigation of Biosupramolecular Systems
Kim, Andre ; Kang, Shin-Won ; Park, Jang-Su ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 55~61
Biosupramolecular systems such as biological membranes usually fluid under physiological conditions
. Therefore, solid-state NMR has been used to investigate biosupramolecular systems. But solid-state NMR spectra contain a large number of overlapping resonances and are rather difficult to analyze. These problem has to be overcome by selective isotope labeling. We constructed a deuterium NMR probe for AM400 NMR spectrometer, which is mainly used for liquid samples. To overcome the fluidity problem, a saddle type coil was designed. The efficiency was systematically investigated for two kinds of coil geometry, solenoid and saddle types. Our results suggest that solenoids are superior to saddle type coils in the sensitivity. However, the letter fits better to fluid samples such as biosupramolecular systems.
NMR Signal Assignments of the Stereochemical Cycloadducts of Bicyclolactone via Diels-Alder Reaction
Kim, Dae-Sung ; Seo, Chan-Woo ; Cho, Cheon-Gyu ; Won, Ho-Shik ;
Journal of the Korean Magnetic Resonance Society, volume 8, issue 1, 2004, Pages 62~69
Bicyclolactones obtained from the Diels-Alder cycloaddition of 3,5-dibromo-2-pyrone can undergo various palladium catalyzed cross coupling reactions to afford aryl bicyclolactones. The resulting coupled products can be readily converted into various 3-OH cyclohexenes via lactone ring openings, while those bearing dienyl units underwent highly diastereoselective Diels-Alder cycloadditions with selected dienophiles to funish multiply functionalized polycarbocycles. Bromo-bicyclic diene furnished two different diastereomers endo-form (62%) and exo-form (38%) upon cycloadditions with N-Et maleimide (NEM), and their stereochemistries were identified with NMR.