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Yi, Jong-Jae,Kim, Won-Je,Rhee, Jin-Kyu,Lim, Jongsoo,Lee, Bong-Jin,Son, Woo Sung Korean Magnetic Resonance Society 2017 Journal of the Korean Magnetic Resonance Society Vol.21 No.1
Dynamic properties of proteins can present key information on protein-ligand and protein-protein interaction. Despite their usefulness, the properties of protein dynamics have not been obtained easily due to protein stability and short-term measurement. Here, it is shown that combined method for analysis of dynamical properties. It utilizes predicted order parameter and NMR relaxation data such as $T_1$, $T_2$, and heteronuclear NOE. The suggested method could be used to know the flexibility of protein roughly without precise dynamical parameters such as order parameters through model-free analysis.
Sang-Yeon Lee,Hyun Been Choi,Mina Park,Il Soon Choi,Jieun An,Ami Kim,Eunku Kim,Nahyun Kim,Jin Hee Han,Min young Kim,Seung min Lee,Doo-Yi Oh,Bong Jik Kim,Nayoung Yi,Nayoung, K. D. Kim,Chung Lee,Woong-Y 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
Loss-of-function variant in the gene encoding the KCNQ4 potassium channel causes autosomal dominant nonsyndromic hearing loss (DFNA2), and no effective pharmacotherapeutics have been developed to reverse channel activity impairment. Phosphatidylinositol 4,5-bisphosphate (PIP2), an obligatory phospholipid for maintaining KCNQ channel activity, confers differentialpharmacological sensitivity of channels to KCNQ openers. Through whole-exome sequencing of DFNA2 families, we identified three novel KCNQ4 variants related to diverse auditory phenotypes in the proximal C-terminus (p.Arg331Gln), the C-terminus of the S6 segment (p.Gly319Asp), and the pore region (p.Ala271_Asp272del). Potassium currents in HEK293T cells expressing each KCNQ4 variant were recorded by patch-clamp, and functional recovery by PIP2 expression or KCNQ openers was examined. In the homomeric expression setting, the three novel KCNQ4 mutant proteins lost conductance and were unresponsive to KCNQ openers or PIP2 expression. Loss of p.Arg331Gln conductance was slightly restored by a tandem concatemer channel (WT-p.R331Q), and increased PIP2 expression further increased the concatemer current to the level of the WT channel. Strikingly, an impaired homomeric p.Gly319Asp channel exhibited hyperactivity when a concatemer (WT-p.G319D), with a negative shift in the voltage dependence of activation. Correspondingly, a KCNQ inhibitor and chelation of PIP2 effectively downregulated the hyperactive WTp. G319D concatemer channel. Conversely, the pore-region variant (p.Ala271_Asp272del) was nonrescuable under any condition. Collectively, these novel KCNQ4 variants may constitute therapeutic targets that can be manipulated by the PIP2 level and KCNQregulating drugs under the physiological context of heterozygous expression. Our research contributes to the establishment of a genotype/mechanism-based therapeutic portfolio for DFNA2.
Electromagnetic wave absorption properties of composites with ultrafine hollow magnetic fibers
Yi, Jin Woo,Lee, Sang Bok,Kim, Jin Bong,Lee, Sang Kwan,Park, O Ok Elsevier 2014 Journal of magnetism and magnetic materials Vol.361 No.-
Ultrafine hollow magnetic fibers were prepared by electroless plating using hydrolyzed polyester fiber as a sacrificial substrate. These hollow fibers can be served for lightweight and efficient electromagnetic (EM) absorbing materials. As observed from SEM and EDS analysis, hollow structures consisting of Ni inner layer and Fe or Fe-Co outer layer were obtained. By introducing Co onto Fe, oxidation of the Fe layer was successfully prevented making it possible to enhance the complex permeability compared to a case in which only Fe was used Polymeric composites containing the hollow fibers with different weight fractions and fiber lengths were prepared by a simple mixing process. The electromagnetic wave properties of the composites were measured by a vector network analyzer and it was found that the hollow magnetic fibers show a clear resonance peak of the complex permittivity around the X-band range (8-12 GHz) and the resonance frequency strongly depends on the fiber concentration and length. A possible explanation for the unique resonance is that the hollow fibers possess relatively low electrical conductivity and a long mean free path due to their oxidized phase and hollow structure. The calculated FM wave absorption with the measured FM wave properties showed that the composite containing 30 wt% hollow Ni/Fe-Co (7:3) fibers in length of 180 mu m exhibited multiple absorbance peaks resulting in a broad absorption bandwidth of 4.2 GHz. It is obvious that this multiple absorbance is attributed to the resonance characteristic of the composite. (C) 2014 Elsevier B.V. All rights reserved
Yi, Sang-Bong,Oh, Chang Whan,Lee, Seung-Yeol,Choi, Seon-Gyu,Kim, Taesung,Yi, Keewook Elsevier 2016 Lithos Vol.246 No.-
<P><B>Abstract</B></P> <P>Triassic coeval mafic and intermediate magmatism occurred in the area suggested to be the southern margin of the North China Craton (NCC) in the Gyeonggi Massif (GM) of the Korean Peninsula. This study investigates aspects of the mafic and intermediate magmatism using SHRIMP zircon ages and whole-rock chemical and isotopic Sr–Nd data. The mafic and intermediate rocks intruded into a basement paragneiss in three areas (Yangpyeong, Odesan and Yangyang) within the GM at ca. 230Ma. The paragneiss was metamorphosed in both the Paleoproterozoic and Triassic. Gabbros (hornblende gabbro and pyroxene–mica gabbro) from the study areas exhibit strong light REE (LREE) enrichment relative to chondrite (La<SUB>N</SUB>/Yb<SUB>N</SUB> =11.1–30.6) and a high LILE/HFSE pattern, Ta–Nb–P–Ti troughs and positive Ba–K–Pb–Sr spikes on the N-MORB-normalized multi-element variation diagram. These features are typical characteristics of arc-related gabbros. The gabbros also show strongly enriched initial isotopic compositions (<SUP>87</SUP>Sr/<SUP>86</SUP>Sr<SUB>(i)</SUB> =0.7100–0.7137; ε<SUB>Nd</SUB>(t)=−13.1 to −19.7). The coeval intermediate intrusive rocks also exhibit whole-rock chemical and isotopic features (<SUP>87</SUP>Sr/<SUP>86</SUP>Sr<SUB>(i)</SUB> =0.7099–0.7143; ε<SUB>Nd</SUB>(t)=−10.8 to −18.6) similar to those of the gabbros. The mafic and intermediate intrusive rocks plot in the within-plate and/or post-collisional fields on tectonic discrimination diagrams. These data indicate that the mafic and intermediate magmatism in the study areas occurred during the Triassic post-collisional relaxation period via partial melting of sub-continental lithospheric mantle (SCLM) that was enriched in a subduction environment prior to (or during) the Permo-Triassic continental collision between the NCC and the South China Craton (SCC). The highly enriched mantle signatures revealed by the gabbros from the study areas are matched to the enriched features identified in Cretaceous mafic igneous rocks (ca. 130Ma) on the southern margin of the NCC. Thus, this study suggests that the lithospheric mantle beneath the Yangpyeong, Odesan and Yangyang areas are comparable to the SCLM of the NCC southern margin. The highly enriched nature of mafic and intermediate rocks from the study areas indicates that their source is the SCLM that was metasomatized by Permian to early Triassic subduction–continental collision processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mafic and intermediate magmatism may have occurred during post-collisional setting. </LI> <LI> The magma source of these rocks appears to be the enriched sub-continental lithospheric mantle (SCLM). </LI> <LI> This lithospheric mantle is comparable to the SCLM of the southern margin of the North China Craton. </LI> </UL> </P>
Yi, Young-Joo,Lee, In-Kyoung,Lee, Sang-Myeong,Yun, Bong-Sik The Korean Society of Mycology 2016 Mycobiology Vol.44 No.1
Davallialactone (DAVA) is a hispidin analogue derived from the medicinal fungus Phellinus baumii. We examined the effect of DAVA on in vitro fertilization (IVF) of pigs. Boar spermatozoa were incubated in fertilization medium with varying concentrations of DAVA, then sperm motility and reactive oxygen species (ROS) level were evaluated. Higher sperm motility was found following the addition of 0.5 or $1{\mu}M$ DAVA after incubation than addition of other concentrations or controls. ROS level decreased significantly with the addition of DAVA. The rate of normal fertilization was higher in the presence of $1{\mu}M$ DAVA (65.1%) than were those of other concentrations or controls (45.4~59.4%), and the highest total fertilization rate (mono- and polyspermic oocytes) was observed at $1{\mu}M$ DAVA (83%). In conclusion, addition of DAVA to fertilization medium improved sperm motility, and reduced ROS level so as to potentially improve sperm-oocyte binding in IVF, suggesting the potential of a compound isolated from mushrooms in assisted reproductive technology for humans and animals.
Characterization of pH-dependent structural properties of hydrolase PncA using NMR
Yi, Jong-Jae,Kim, Won-Je,Rhee, Jin-Kyu,Lim, Jongsoo,Lee, Bong-Jin,Son, Woo Sung Korean Magnetic Resonance Society 2018 Journal of the Korean Magnetic Resonance Society Vol.22 No.4
Catalytic enzyme Pyrazinamidase (PncA) from Mycobacterium tuberculosis can hydrolyze substrate pyrazinamide (PZA) to pyrazoic acid (POA) as active form of compound. Using NMR spectroscopy, pH-dependent catalytic properties were monitored including metal binding mode during converting PZA to POA. There seems to be a conformational change through zinc binding in active site from the perturbation of peak intensities in series of 2D HSQC spectra the conformation changes through zinc binding.
Identification of Enzymatic Catalysis of PncA using <sup>1</sup>H-NMR
Yi, Jong-Jae,Kim, Won-Je,Rhee, Jin-Kyu,Lim, Jongsoo,Lee, Bong-Jin,Son, Woo Sung Korean Magnetic Resonance Society 2017 Journal of the Korean Magnetic Resonance Society Vol.21 No.3
Pyrazinamidase (PncA) from Mycobacterium tuberculosis is the hydrolytic enzyme (hydrolase) that can hydrolyze substrate PZA to active form pyrazoic acid (POA). To investigate hydrolytic reaction of M. tuberculosis PncA, 1D NMR spectra were monitored at various molar ratios of PncA and PZA. The line-width of PZA was changed as PncA was added into PZA with different molar ratios. These results suggested that determination of PncA enzymatic activity could potentially serve as an indirect measure of PZA susceptibility.