• Title/Summary/Keyword: n-Helix

Search Result 133, Processing Time 0.024 seconds

Digital Diplomacy via Social Networks: A Cross-National Analysis of Governmental Usage of Facebook and Twitter for Digital Engagement

  • Ittefaq, Muhammad
    • Journal of Contemporary Eastern Asia
    • /
    • v.18 no.1
    • /
    • pp.49-69
    • /
    • 2019
  • Over the last couple of years, digital diplomacy has become a fascinating area of research among Mass Communication, Peace and Conflict Studies, and International Affairs scholars. Social media and new technology open up new avenues for governments, individuals, and organizations to engage with foreign audiences. However, developing countries' governments are still lacking in the realization of the potential of social media. This study aims to analyze the usage of social media (Facebook & Twitter) by the two biggest countries in South Asia (Pakistan and India). I selected 10 government officials' social media accounts including prime ministers', national press offices', military public relations offices', public diplomacy divisions', and ministries of foreign offices' profiles. The study relies on quantitative content analysis and a comparative research approach. The total number of analyzed Twitter tweets (n=1,015) and Facebook posts (n=1,005) include 10 accounts, five from each country. In light of Kent and Taylor's (1998) dialogic communication framework, the results indicate that no digital engagement and dialogue occurs between government departments and the public through social networking sites. Government departments do not engage with local or foreign audiences through digital media. When comparing both countries, results reveal that India has more institutionalized and organized digital diplomacy. In terms of departmental use of social media, the digital diplomacy division and foreign office of India is more active than other government departments in that nation. Meanwhile, Pakistan's military public relations office and press office is more active than its other government departments. In conclusion, both countries realize the potential of social media in digital diplomacy, but still lack engagement with foreign audiences.

Phenylarsine Oxide and Adenosine-sensitive Trans-golgi Complex Targeting of GFP Fused to Modified Sulfatide-binding Peptide (Phenylarsine oxide와 adenosine에 민감한 sulfatide 결합 펩타이드의 trans-golgi network 타기팅)

  • Jun, Yong-Woo;Lee, Jin-A;Jang, Deok-Jin
    • Journal of Life Science
    • /
    • v.28 no.2
    • /
    • pp.162-169
    • /
    • 2018
  • Many cytoplasmic proteins are targeted to the cytoplasmic membrane of the trans-Golgi network (TGN) via an N-terminal short helix. We previously showed that the 20 N-terminal amino acids of Aplysia phosphodiesterase 4 (ApPDE4) long form are sufficient for its targeting to the plasma membrane and the TGN. The N-terminus of the ApPDE4 long form binds to PI4P and sulfatide in vitro. Therefore, in order to decipher the roles of sulfatide in Golgi complex targeting, we examined the cellular localization of sulfatide-binding peptides. In this study, we found that enhanced green fluorescent protein (EGFP) fused to the C-terminus of modified sulfatide- and heparin-binding peptides (mHSBP-EGFP) was localized to the TGN. On the other hand, its mutant, in which tryptophan was replaced with an alanine, leading to the impairment of heparin and sulfatide binding, was localized to cytosol. We also found that the TGN targeting of mHSBP-EGFP is impaired by the treatment of antimycin A, phenylarsine oxide (PAO), and adenosine but not a high concentration of wortmannin. These results suggest that PAO and adenosine-sensitive kinases, including phosphatidylinositol 4-kinase II, may play key roles in the recruitment of mHSBP-EGFP.

Molecular Characterization and Phylogenetic Analysis of Season Influenza Virus Isolated in Busan during the 2006-2008 Seasons (부산지역에서 유행한 계절인플루엔자바이러스의 유전자 특성 및 계통분석('06-'08 절기))

  • Park, Yon-Koung;Kim, Nam-Ho;Choi, Seung-Hwa;Lee, Mi-Oak;Min, Sang-Kee;Kim, Seong-Joon;Cho, Kyung-Soon;Na, Young-Nan
    • Journal of Life Science
    • /
    • v.20 no.3
    • /
    • pp.365-373
    • /
    • 2010
  • To monitor newly emerged influenza virus variants and to investigate the prevalence pattern, our laboratory performed isolation of the viruses from surveillance sentinel hospitals. In the present study, we analysed influenza A/H1N1, A/H3N2, B viruses isolated in Busan during the 2006/07 and 2007/08 seasons by sequence analysis of the hemagglutinin (HA1 subunit) and neuraminidase (NA) genes. The isolates studied here were selected by the stratified random sample method from a total of 277 isolates, in which 15 were A/H1N1, 16 were A/H3N2 and 29 were B. Based on the phylogenetic tree, the HA1 gene showed that A/H1N1 isolates had a 96.7% to 97.7% homology with the A/Brisbane/59/2007, A/H3N2 isolates had a 98.4% to 99.7% homology with the A/Brisbane/10/2007, and B isolates had a 96.5% to 99.7% homology with the B/Florida/4/2006(Yamagata lineage), which are all the vaccine strains for the Northern Hemisphere in 2008~2009 season. In the case of the NA gene, A/H1N1 isolates had 97.8% to 98.5% homologies, A/H3N2 isolates had 98.9% to 99.4% homologies, and B isolates had 98.9% to 100% homologies with each vaccine strain in the 2008~2009 season, respectively. Characterization of the hemagglutinin gene revealed that amino acids at the receptor-binding site and N-linked glycosylation site were highly conserved. These results provide useful information for the control of influenza viruses in Busan and for a better understanding of vaccine strain selection.

Production of pediocin by Chemical Synthesis and Bactericidal Mode of Action

  • Koo, Min-Seon;Kim, Wang-June;Kwon, Dea-Young;Min, Kyung-Hee
    • Proceedings of the Korean Society for Applied Microbiology Conference
    • /
    • 2001.06a
    • /
    • pp.149-153
    • /
    • 2001
  • To investigate the mode of bactericidal action for antimicrobial peptide, pediocin, synthetic and mutant pediocins were prepared by direct chemical synthesis. Native pediocin was purified from Pedio-coccus acidilactici M and its conformational structure and bactericidal functions were analyzed and compared to synthetic pediocin. Schematic mode of pediocin actions, how pediocin binds on the target cell membrane, penetrates and makes tunnel are proposed. For these purposes, primary and secondary structures of pediocin was analyzed and disulfide bond assignment was also done. The pediocin purified from P. acidilactici M had high effective bactericidal ability against gram positive bacteria, especially Listeria monocytogenes and was very stable at extreme pHs and even at high temperatures such as autoclaving temperature (121$^{\circ}C$). Pediocin was consisted of 44 amino acids with four cysteines. Novel synthetic peptides were achieved by solid phase peptide synthesis(SPPS) method. To explain the function of cysteine in C-terminal region, mutant pediocin, Ped[C24A+C44A], was synthesized and their structural and biological functions were analyzed. Second mutant pediocin, Ped[KllE], was prepared to explain the function of lysine at 11 of N-terminal part of pediocin, especially loop of $\beta$-sheet, and to predict the initial binding site of pediocin. The native and synthetic pediocins was showed random coil conformation by spectropolarimetry in moderate conditions. This conformation was observed in extreme conditions such as high temperature and low and high pHs, also. Circular dichroism(CD) data also showed the existence of $\beta$-turn structure in N-terminal part both native and synthetic pediocins. A structural model for pediocin predicts that 18 amino acids in the N-terminal part of the peptide assume a three-strand $\beta$-sheet conformation. This random coil in C-terminal part of pediocin was converted to folding structure, helix structure, in nonpolar solvents such as alcohol and TFE. The disulfide bond between $^{9}$ Cys and $^{14}$ Cys was concrete and inevitable, however, evidences of disulfide bond between $^{24}$ Cys and $^{44}$ Cys was not. Data of Ped[C24A+C44A], pediocin mutant showed that $^{44}$ Cys was required during killing the target cells but not inevitable, since Ped[C24A+C44A] still have bactericidal activity but much less than native pediocin. Another pediocin mutant, Ped[KllE], had still bactericidal activity, was controversial to propose that positive charge like as $^{11}$ Lys in loop or hinge in bacteriocin bound or helped to binding to microorganism with electrostatic interaction between cell membrane especially teichoic acid and positive amino acid nonspecifically. The conformation of pediocin among native, synthetic and mutant pediocins did not show big difference. The conformations between oxidized and reduced pediocin were almost similar regardless of native or synthetic.

  • PDF

Structure-activity relationships of cecropin-like peptides and their interactions with phospholipid membrane

  • Lee, Eunjung;Jeong, Ki-Woong;Lee, Juho;Shin, Areum;Kim, Jin-Kyoung;Lee, Juneyoung;Lee, Dong Gun;Kim, Yangmee
    • BMB Reports
    • /
    • v.46 no.5
    • /
    • pp.282-287
    • /
    • 2013
  • Cecropin A and papiliocin are novel 37-residue cecropin-like antimicrobial peptides isolated from insect. We have confirmed that papiliocin possess high bacterial cell selectivity and has an ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$ and from $Ala^{25}$ to $Val^{35}$, linked by a hinge region. In this study, we demonstrated that both peptides showed high antimicrobial activities against multi-drug resistant Gram negative bacteria as well as fungi. Interactions between these cecropin-like peptides and phospholipid membrane were studied using CD, dye leakage experiments, and NMR experiments, showing that both peptides have strong permeabilizing activities against bacterial cell membranes and fungal membranes as well as $Trp^2$ and $Phe^5$ at the N-terminal helix play an important role in attracting cecropin-like peptides to the negatively charged bacterial cell membrane. Cecropin-like peptides can be potent peptide antibiotics against multi-drug resistant Gram negative bacteria and fungi.

Molecular Dynamics of the C-Terminal Domain Mouse CDT1 Protein

  • Khayrutdinov, Bulat I.;Bae, Won-Jin;Kim, Jeong-Ju;Hwang, Eun-Ha;Yun, Young-Mi;Ryu, Kyoung-Seok;Cheong, Hae-Kap;Kim, Yu-Gene;Cho, Yun-Je;Jeon, Young-Ho;Cheong, Chae-Joon
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.11 no.1
    • /
    • pp.30-41
    • /
    • 2007
  • The backbone molecular dynamics of the C-terminal part of the mouse Cdt1 protein (tCdt1, residues 420-557) was studied by high field NMR spectroscopy. The Secondary structure of this protein was suggested by analyzing of chemical shift of backbone atoms with programs TALOS and PECAN, together with NOE connectivities from 3D $^{15}N-HSQC-NOESY$ data. Measurement of dynamic parameters $T_1,\;T_2$ and NOE and limited proteolysis experiment provided information for domain organization of tCdt1(420-557). Analysis of the experimental data showed that the C-terminal part of the tCdt1 has well folded domain for residues 455-553. The residues 420-453 including ${\alpha}-helix$ (432-441) are flexible and probably belong to other functional domain in intact full length Cdt1 protein.

  • PDF

University Linkages in Technology Clusters of Emerging Economies - Exploratory Case Studies from Cyberjaya, Malaysia - a Greenfield Development and Cyberabad, India - a Brownfield Development

  • Mohan, Avvari V.;Ejnavarzala, Haribabu;Lakshmi, C.N.
    • World Technopolis Review
    • /
    • v.1 no.1
    • /
    • pp.42-55
    • /
    • 2012
  • This paper is concerned with the linkages between universities and industry in the information and communications technology (ICT) in Cyberjaya, Malaysia and Cyberabad, India. In the case of the ICT cluster of Cyberjaya, the context can be termed as greenfield cluster development as the whole project is developed from scratch. In the case of Cyberabad, India, the context can be seen as a brownfield development, where the cluster developed based on existing and new organisations in a region. There is extant literature in research, be it from an Innovation systems or a Triple Helix perspective that has given significant attention to the importance of universities as engines of growth and also about the significance of their linkages with industry innovation in regions. But as argued by scholars like Chaminade et al, most of these papers tend to ignore the specific context in which this interaction between the university and the industry takes place - this study aims to fill this gap through an exploratory study from emerging economies and in a greenfield and brownfield contexts. The findings from the two cases point towards (1) the role of intermediary organisations in developing the linkages, (2) the issue of capabilities of universities for supporting industry development and (3) university-industry linkages are different in greenfield and brown field developments. The paper presents the cases and discusses the findings and provides insights to cluster development officials and policy makers and implications to researchers for developing studies of university-industry from a capabilities and context perspectives.

The Role of Residues 103, 104, and 278 in the Activity of SMG1 Lipase from Malassezia globosa: A Site-Directed Mutagenesis Study

  • Lan, Dongming;Wang, Qian;Popowicz, Grzegorz Maria;Yang, Bo;Tang, Qingyun;Wang, Yonghua
    • Journal of Microbiology and Biotechnology
    • /
    • v.25 no.11
    • /
    • pp.1827-1834
    • /
    • 2015
  • The SMG1 lipase from Malassezia globosa is a newly found mono- and diacylglycerol (DAG) lipase that has a unique lid in the loop conformation that differs from the common alpha-helix lid. In the present study, we characterized the contribution of three residues, L103 and F104 in the lid and F278 in the rim of the binding site groove, on the function of SMG1 lipase. Site-directed mutagenesis was conducted at these sites, and each of the mutants was expressed in the yeast Pichia pastoris, purified, and characterized for their activity toward DAG and p-nitrophenol (pNP) ester. Compared with wild-type SMG1, F278A retained approximately 78% of its activity toward DAG, but only 11% activity toward pNP octanoate (pNP-C8). L103G increased its activity on pNP-C8 by approximately 2-fold, whereas F104G showed an approximate 40% decrease in pNP-C8 activity, and they both showed decreased activity on the DAG emulsion. The deletion of 103-104 retained approximately 30% of its activity toward the DAG emulsion, with an almost complete loss of pNP-C8 activity. The deletion of 103-104 showed a weaker penetration ability to a soybean phosphocholine monolayer than wild-type SMG1. Based on the modulation of the specificity and activity observed, a pNP-C8 binding model for the ester (pNP-C8, N102, and F278 form a flexible bridge) and a specific lipid-anchoring mechanism for DAG (L103 and F104 serve as "anchors" to the lipid interface) were proposed.

Crystal Structure of Cytochrome cL from the Aquatic Methylotrophic Bacterium Methylophaga aminisulfidivorans MPT

  • Ghosh, Suparna;Dhanasingh, Immanuel;Ryu, Jaewon;Kim, Si Wouk;Lee, Sung Haeng
    • Journal of Microbiology and Biotechnology
    • /
    • v.30 no.8
    • /
    • pp.1261-1271
    • /
    • 2020
  • Cytochrome cL (CytcL) is an essential protein in the process of methanol oxidation in methylotrophs. It receives an electron from the pyrroloquinoline quinone (PQQ) cofactor of methanol dehydrogenase (MDH) to produce formaldehyde. The direct electron transfer mechanism between CytcL and MDH remains unknown due to the lack of structural information. To help gain a better understanding of the mechanism, we determined the first crystal structure of heme c containing CytcL from the aquatic methylotrophic bacterium Methylophaga aminisulfidivorans MPT at 2.13 Å resolution. The crystal structure of Ma-CytcL revealed its unique features compared to those of the terrestrial homologues. Apart from Fe in heme, three additional metal ion binding sites for Na+, Ca+, and Fe2+ were found, wherein the ions mostly formed coordination bonds with the amino acid residues on the loop (G93-Y111) that interacts with heme. Therefore, these ions seemed to enhance the stability of heme insertion by increasing the loop's steadiness. The basic N-terminal end, together with helix α4 and loop (G126 to Y136), contributed positive charge to the region. In contrast, the acidic C-terminal end provided a negatively charged surface, yielding several electrostatic contact points with partner proteins for electron transfer. These exceptional features of Ma-CytcL, along with the structural information of MDH, led us to hypothesize the need for an adapter protein bridging MDH to CytcL within appropriate proximity for electron transfer. With this knowledge in mind, the methanol oxidation complex reconstitution in vitro could be utilized to produce metabolic intermediates at the industry level.

Effects of Substitutions of Gln16 and Asp18 with Phe or Tyr in HP(2-20) on its Structure and Antimicrobial Activity

  • Kim, Jin-Kyoung;Lee, Ju-Un;Kim, Woong-Hee;Park, Yoon-Kyung;Hahm, Kyung-Soo;Kim, Yang-Mee
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.13 no.1
    • /
    • pp.27-34
    • /
    • 2009
  • HP (2-20), a 19-residue peptide derived from the N-terminus of Helicobacter pylori Ribosomal Protein L1, has antimicrobial activity but is not cytotoxic to human erythrocytes. Previously, we have synthesized several analogue peptides to investigate the effects of substitutions on the structure and antimicrobial activity. Substitution of $Gln^{16}$ and $Asp^{18}$ with Trp (Anal 3) caused a dramatic increase in bacterial and fungal lytic activities. In this study, analogue peptides were synthesized to investigate the effects of substitution of Gin and Asp with Phe (Anal 6) or Tyr (Anal 7) in HP (2-20) on its structure and antimicrobial activity. Substitution of Gin and Asp with hydrophobic aromatic residues at position 16 and 18 of HP (2-20) caused increase in antibiotic activity without hemolytic effect. Substitution of Gin and Asp with Trp and Try increased antibiotic activity of HP (220) twice more compared to substitution with Phe. The tertiary structures of Anal 6 and Anal 7 in SDS micelles has been investigated using NMR spectroscopy. The structures revealed that substitutions of the aromatic residues at C-terminus resulted in longer and well defined alpha-helix and improved their antibacterial activities