• Title/Summary/Keyword: helix

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Structural characterization of HBx-interacting protein using NMR spectroscopy

  • Lee Young-Tae;Kim Byoung-Kook;Kim Key-Sun;Choi Byong-Seok
    • Journal of the Korean Magnetic Resonance Society
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    • v.9 no.2
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    • pp.122-137
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    • 2005
  • The hepatitis B virus X protein (HBx) is highly linked with liver diseases and the development of hepatocellular carcinoma. HBx-interacting protein (XIP) has been shown to abolish the transactivation functions of HBx. Here, we define the structural characteristics and HBx binding properties of XIP. Under physiological conditions, XIP was composed mainly of random-coils but significant helicity was induced in the hydrophobic condition. NMR spectroscopy defined the secondary structure of XIP in the presence of sodium dodecyl sulfate. Four putative helices were mapped to the amino acids 8-12, 32-38, 42-54 and 82-91. Any deletion of defined putative helices in XIP led to loss of binding to HBx, and truncated mutant lacking last putative helix decreased helicity more than that it could. Our results suggest that XIP requires its entire sequence for HBx binding and it may be under drastic conformational change when binds to HBx.

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Backbone 1H, 15N, and 13C resonance assignments and secondary structure prediction of SAV2228 (translation initiation factor-1) from Staphylococcus aureus

  • Kim, Do-Hee;Jang, Sun-Bok;Lee, Bong-Jin
    • Journal of the Korean Magnetic Resonance Society
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    • v.16 no.2
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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.

Purification and NMR studies on Phosphatase domain of UBLCP1

  • Oh, Hyo-Sun;Ko, Sung-Geon;Moon, Sun-Jin;Shin, Hang-Cheol;Lee, Weon-Tae
    • Journal of the Korean Magnetic Resonance Society
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    • v.13 no.2
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    • pp.126-134
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    • 2009
  • UBLCP1 is composed of Ubiquitin Like domain and RNA Polymerase II Phosphatase I domain. Phosphatase domain (25.9KDa) has been cloned into the E.coli using pET32a vector with TEV protease cleavage site and successfully purified as a monomer using affinity chromatography and histidine tag was cleaved with TEV protease for structural studies. Our results indicated that the Phosphatase domain showed well-defined folded structure based on data from one-dimensional and two-dimensional NMR spectroscopy. Data form circular dichroism also suggested that Phosphatase domain consisted of both ${\alpha}$ -helix and ${\beta}$ -sheet. This information will be used for detailed structural study of UBLCP1.

Simple Aesthetic Correction for Patients with Acute Auriculocephalic Angle

  • Lee, Byung Mi;Kang, Seok Joo;Sun, Hook
    • Archives of Craniofacial Surgery
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    • v.16 no.1
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    • pp.24-28
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    • 2015
  • Background: Acute auriculocephalic angle refers to an ear with helix that is spaced closely to the cranium. An increasing number of patients with acute auriculocephalic angle wish to undergo corrective operation for aesthetic purposes. However, there is a paucity of data regarding acute auriculocephalic angle. This paper proposes a treatment protocol for patients with acute auriculocephalic angle. Methods: We performed a retrospective analysis of patients undergoing acute auriculocephalic angle (4 patients, 6 ears). Patient records were reviewed for demographic data as well as auricular measurements at preoperative, immediate postoperative and final follow-up evaluations. Results: All of the patients were men with a mean age of 36.5 years (range, 23-52 years). The mean follow-up period was 47.5 months (range, 28-60 months). Postoperative auriculocephalic angle was close to the normal auriculocephalic angle ($25^{\circ}-30^{\circ}$) without notable scars. Moreover, the patients had minimal contractions of the skin flaps without any hematoma or relapse. Conclusion: We propose the following three treatment protocols for patients with acute auriculocephalic angle: the posterior auricular muscle should be sufficiently released, the mastoid area should be augmented using implants, the skin should be repositioned with a superior auricular flap.

Functional Studies of Cysteine Residues in Human Glutathione S-Transferase P1-1 by Site-Directed Mutagenesis

  • Park, Hui Jung;Lee, Gwang Su;Gong, Gwang Hun
    • Bulletin of the Korean Chemical Society
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    • v.22 no.1
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    • pp.77-83
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    • 2001
  • To gain further insight into the relationship between structure and function of glutathione S-transferase (GST), the four cysteine mutants, C14S, C47S, C101S and C169S, of human GST P1-1 were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized glutathione (GSH). The catalytic activities of the four mutant enzymes were characterized with five different substrates as well as by their binding to four different inhibitors. Cys14 seems to participate in the catalytic reaction of GST by stabilizing the conformation of the active-site loop, not in the GSH binding directly. The substitution of Cys47 with serine significantly reduces the affinity of GSH binding, although it does not prevent GSH binding. On the other hand, the substitution of Cys101 with serine appears to change the binding affinity of electrophilic substrate by inducing a conformational change of the $\alpha-helix$ D. Cys169 seems to be important for maintaining the stable conformation of the enzyme. In addition, all four cysteine residues are not needed for the steroid isomerase activity of human glutathione S-transferase P1-1.

A Spring Back Calculation Model for the Sensitivity Analysis of Tube Design Parameters of Helical Steam Generator

  • Kim, Yong-Wan;Kim, Jong-In;Huh, Hyung;Park, Jin-Seok;Kim, Ji-Ho
    • Proceedings of the Korean Nuclear Society Conference
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    • 1999.10a
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    • pp.355.2-355
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    • 1999
  • The spnng back phenomena occurring in the coiling process of a steam generator tube induces the dimensional inaccuracy and makes the coiling procedure difficult. In this research, an analytical model was developed to evaluate the amount of the spring back for SMART steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.rocess.

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In the middle of a perfect storm: political risks of the Belt and Road project at Kyaukphyu, Myanmar

  • Morris, David
    • Journal of Contemporary Eastern Asia
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    • v.20 no.2
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    • pp.210-236
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    • 2021
  • China's Belt and Road Initiative infrastructure connectivity and other projects are presented in much of the discourse as a grand strategy to trap developing nations in debt, to exert asymmetric power and construct a new world economic order. The asymmetric relationship between China and Myanmar might therefore be expected to generate a range of political risks for stakeholders. Myanmar itself presents a "perfect storm" of problems, with dysfunctional governance, civil conflict, under-development and growing economic dependence on China. The Kyaukphyu port project and associated Special Economic Zone in Myanmar's troubled Rakhine state is investigated as a case study of risks on the Belt and Road. While worst case fears China might seize military control of the port appear unlikely, at least in current conditions, empirical observation indicates the complexity on the ground generates an array of other risks - as well as opportunities, should conditions allow. Further, despite challenges and constrained capacity, Myanmar governments have demonstrated agency, including by re-negotiating control and costs of the Kyaukphyu project. The case underlines that conditions are more complicated than simply China's asymmetric power. A sceptical approach is taken to normative discourses in order to build inductive understanding of how stakeholders and local experts perceive dynamics underway. A political risk approach is deployed to develop a framework to identify, analyse and assess risks for actors in relation to the Kyaukphyu project. The research findings are presented on an interim basis, given current constraints on field interviews due to the current crisis.

The Reaction of the Malaysian Stock Market to the COVID-19 Pandemic

  • Mehmood, Waqas;Mohd-Rashid, Rasidah;Aman-Ullah, Attia;Shafique, Owais;Tajuddin, Ahmad Hakimi
    • Journal of Contemporary Eastern Asia
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    • v.20 no.2
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    • pp.63-84
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    • 2021
  • The present study was conducted to understand the turmoil effects of COVID-19 pandemic on the Malaysian stock market during the different periods of the Movement Control Order (MCO). The present study was based on the secondary data extracted from the DataStream and Bloomberg from 2nd January 2020 to 29th May 2020 to evaluate the effects of COVID-19 pandemic on the Malaysian stock market. The findings suggested that during the different periods of the Movement Control Order (MCO) from the 1st January to 29th May 2020, the COVID-19 pandemic adversely affected the performance of KLCI index and all sectoral indices. The weakest performance indices were energy, property, and finance while the least affected indices were healthcare, technology, telecommunications, and media. This paper provides a review of the impacts of COVID-19 pandemic on the Malaysian stock market throughout the different periods of MCO.

Risk Communication Networks in South Korea: The Case of the 2017 Gangneung Wildfire

  • Oh, Jeongmin;Jung, Kyujin;Song, Minsun
    • Journal of Contemporary Eastern Asia
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    • v.20 no.2
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    • pp.85-107
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    • 2021
  • Wildfires have become increasingly common and intense in South Korea because of climate change, but few have recognized the catastrophic level of the problem. Given the significant impact of wildfires, emergency management stakeholders must have effective risk communication structures for rapidly responding to such phenomena and overcoming geographical difficulties. Despite the country spending billions of dollars to build a big databased early warning system, risk communication flow during the 2017 Gangneung wildfire was ineffective, thereby causing substantial economic, social, and environmental losses. To examine the patterns of information exchange in South Korea's risk communication networks and their structural characteristics during the wildfire, we conducted semantic and network analyses of real-time data collected from social media. The results showed that the inefficient flow of risk information prevented emergency responders from adequately assessing the emergency and protecting the population. This study provides new insights into effective risk communication responses to catastrophic events and methods of research on webometric approaches to emergency management.

Renewable energy statecraft and asymmetric interdependence: how the solar energy industry is wielding China with geopolitical power

  • Vasconcelos, Daniel de Oliveira
    • Journal of Contemporary Eastern Asia
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    • v.20 no.2
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    • pp.259-277
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    • 2021
  • This article investigates the geopolitics of the energy transition era, concentrating on China's solar photovoltaic (PV) industry. Authors have noted that the rise of renewables is changing the geopolitical landscape of world energy systems, but these new energy sources carry their own technical characteristics and geopolitical implications. Bearing this in mind, this research answers the questions: What are the structural factors that facilitate China's use of renewable energy to achieve political goals, and what are their implications? In order to analyze the data, I devise an analytical framework based on the energy statecraft literature and contrast rival explanations, particularly the "prosumer theory" and the premise of less geopolitical interdependence in a renewable-centered world. I show that asymmetric interdependence in the solar PV sector is already a reality. China's solar PV industry is a case that suffices all conditions (centrality in industrial capacity, market share, and companies' compliance, but to a lesser extent in critical materials and technological endowments) in the solar PV sector to devise effective strategies aimed at reaping benefits out of its asymmetric interdependence with the rest of the world.