• 제목/요약/키워드: Advanced Chemistry

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The Characterization of Borohydride-Stabilized Nanosilvers in Laponite Sol Using 1H NMR: Its Ligand Exchange Reactions with MUA and TOP

  • Seo, Jae-Seok;Son, Dong-Min;Lee, Han-Na;Kim, Jee-Kwang;Kim, You-Hyuk
    • Bulletin of the Korean Chemical Society
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    • v.30 no.11
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    • pp.2651-2654
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    • 2009
  • In borohydride-protected nanosilvers in laponite sol, the silver particles aggregate to form short chains and a dumbbell shape. The $^{1}H$ NMR measurements in this study represent, to our knowledge, the first observation of proton resonances of borohydride-protected nanosilvers in aqueous solution. Borohydride on nanosilver can be exchanged with 11-mercaptoundecanoic acid (MUA) or trioctylphosphine (TOP). Transmission electron microscopy and UV-Vis spectroscopy data show that the number of aggregated silver nanoparticles decreases upon addition of aforementioned ligands due to the formation of silver MPCs (monolayer-protected clusters). Adsorption of MUA or TOP on nanosilver is confirmed through the observation of broad proton resonances of MPCs in $^{1}H$ NMR spectra.

Expression of a Small Protein Encoded by the 3' Flanking Sequence of the Escherichia coli rnpB Gene

  • Kim, Yool;Han, Kook;Lee, Jung-Min;Kim, Kwang-Sun;Lee, Young-Hoon
    • Bulletin of the Korean Chemical Society
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    • v.28 no.6
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    • pp.1010-1014
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    • 2007
  • M1 RNA is the catalytic component of RNase P, a tRNA-processing enzyme in Escherichia coli. M1 RNA is produced in the cell by transcription of the rnpB gene and subsequent processing at the 3' end. The 3' flanking region of rnpB contains repeated sets of overlapping sequences coding for small proteins. The issue of whether these proteins are expressed remains to be established. In this study, we showed the expression of a small protein encoded by the first repeat within the 3' flanking region of rnpB. Interestingly, protein expression was increased at lower temperatures. The termination efficiency of rnpB terminators was decreased at lower temperatures, suggesting that antitermination is responsible for enhanced protein expression. Moreover, the purified small protein contained M1 RNA, implying a role as a specific RNA-binding protein.

Heterogeneous Sequences of Brain Cytoplasmic 200 RNA Formed by Multiple Adenine Nucleotide Insertions

  • Shin, Heegwon;Lee, Jungmin;Kim, Youngmi;Jang, Seonghui;Kim, Meehyein;Lee, Younghoon
    • Molecules and Cells
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    • v.42 no.6
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    • pp.495-500
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    • 2019
  • Brain cytoplasmic 200 RNA (BC200 RNA), originally identified as a neuron-specific non-coding RNA, is also observed in various cancer cells that originate from non-neural cells. Studies have revealed diverse functions of BC200 RNA in cancer cells. Accordingly, we hypothesized that BC200 RNA might be modified in cancer cells to generate cancerous BC200 RNA responsible for its cancer-specific functions. Here, we report that BC200 RNA sequences are highly heterogeneous in cancer cells by virtue of multiple adenine nucleotide insertions in the internal A-rich region. The insertion of adenine nucleotides enhances BC200 RNA-mediated translation inhibition, possibly by increasing the binding affinity of BC200 RNA for eIF4A (eukaryotic translation initiation factor 4A).

Synthesis, interfacial property, and application of new hybrid anion surfactant containing fluorocarbon and hydrocarbon chains

  • Kang, Eun-kyung;Sohn, Eun-Ho;Jung, Ga Young;Jung, Seon Hwa;Ha, Jong-Wook;Lee, Soo-Bok;Park, In Jun;Lee, Byung Min
    • Journal of Industrial and Engineering Chemistry
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    • v.67
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    • pp.72-79
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    • 2018
  • Hybrid F2HX surfactants bearing a sulfate moiety and both hydrocarbon and fluorocarbon chains were prepared by the reaction of alkyl glycidyl ethers with fluoro-alcohol, and subsequent sulfation. The fluorocarbon number in F2HX was fixed at the shortest number possible (i.e., 2), while the hydrocarbon number (X) in the second chain was varied between 2, 4, 6, and 8. Their surface-active properties and emulsion stabilities were systematically estimated as a function of the X. Among them, F2H8 exhibited the optimal surfactant performance, which was comparable to previously reported surfactants and it was successfully applied in the emulsion polymerization of vinylidene fluoride.