• Title/Summary/Keyword: molecular structures

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Deciphering the molecular mechanisms underlying the plasma membrane targeting of PRMT8

  • Park, Sang-Won;Jun, Yong-Woo;Choi, Ha-Eun;Lee, Jin-A;Jang, Deok-Jin
    • BMB Reports
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    • v.52 no.10
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    • pp.601-606
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    • 2019
  • Arginine methylation plays crucial roles in many cellular functions including signal transduction, RNA transcription, and regulation of gene expression. Protein arginine methyltransferase 8 (PRMT8), a unique brain-specific protein, is localized to the plasma membrane. However, the detailed molecular mechanisms underlying PRMT8 plasma membrane targeting remain unclear. Here, we demonstrate that the N-terminal 20 amino acids of PRMT8 are sufficient for plasma membrane localization and that oligomerization enhances membrane localization. The basic amino acids, combined with myristoylation within the N-terminal 20 amino acids of PRMT8, are critical for plasma membrane targeting. We also found that substituting Gly-2 with Ala [PRMT8(G2A)] or Cys-9 with Ser [PRMT8(C9S)] induces the formation of punctate structures in the cytosol or patch-like plasma membrane localization, respectively. Impairment of PRMT8 oligomerization/dimerization by C-terminal deletion induces PRMT8 mis-localization to the mitochondria, prevents the formation of punctate structures by PRMT8(G2A), and inhibits PRMT8(C9S) patch-like plasma membrane localization. Overall, these results suggest that oligomerization/dimerization plays several roles in inducing the efficient and specific plasma membrane localization of PRMT8.

MODELLING THE 3 MICRON REGION IN AKARI IRC SPECTRA

  • Hammonds, Mark;Mori, Tamami;Usui, Fumihiko;Onaka, Takashi
    • Publications of The Korean Astronomical Society
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    • v.32 no.1
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    • pp.93-95
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    • 2017
  • The existence of polycyclic aromatic hydrocarbons (PAHs) astronomically is well accepted, but the specific molecular forms observed remain uncertain. To better understand the molecular structures which may be present along a given sightline, the $3.0-3.6{\mu}m$ region is modelled with careful consideration given to the underlying sub-features arising from specific structures within emitting molecules.

Synthesis and Molecular Structures of $2-SC_4H_3CH=NN(H)C_6H_5 and (GaMe_2)_2(2-SC_4H_3CH=NNC_6H_5)_2$ ($2-SC_4H_3CH=NN(H)C_6H_5$$(GaMe_2)_2(2-SSC_4H_3CH=NNC_6H_5)_2$의 합성과 분자 구조)

  • 박권일;김용기;조성일
    • Korean Journal of Crystallography
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    • v.11 no.1
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    • pp.46-51
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    • 2000
  • The molecular structures of 2-SC₄H₃CH=NN(H)C/sub 6/H/sub 5/(C/sub 11/H/sub 10/N₂S) and (GaMe₂)₂(2-SC₄H₃CH=NNC/sub 6/H/sub 5/)₂(C/sub 26/H/sub 30/Ga₂N₄S₂) have been determined by X-ray diffraction. Crystallographic data for 2-SC₄H₃CH=NN(H)C/sub 6/H/sub 5/:orthorhombic space group P2₁2₁2₁, a=6.108(1)Å, b=7.593(1)Å, c=22.356(2)Å, V=1037.1(3)ų, Z=4, R=0.0613. Crystallographic data for (GaMe₂)₂(2-SC₄H₃CH=NNC/sub 6/H/sub 5/)₂:monoclinic space group P2₁/n, a=15.996(2) Å, c=9.879(3)Å, β=100.07.(2)°, V=2764.599)ų, Z=4, R=0.0503.

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The cellular basis of dendrite pathology in neurodegenerative diseases

  • Kweon, Jung Hyun;Kim, Sunhong;Lee, Sung Bae
    • BMB Reports
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    • v.50 no.1
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    • pp.5-11
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    • 2017
  • One of the characteristics of the neurons that distinguishes them from other cells is their complex and polarized structure consisting of dendrites, cell body, and axon. The complexity and diversity of dendrites are particularly well recognized, and accumulating evidences suggest that the alterations in the dendrite structure are associated with many neurodegenerative diseases. Given the importance of the proper dendritic structures for neuronal functions, the dendrite pathology appears to have crucial contribution to the pathogenesis of neurodegenerative diseases. Nonetheless, the cellular and molecular basis of dendritic changes in the neurodegenerative diseases remains largely elusive. Previous studies in normal condition have revealed that several cellular components, such as local cytoskeletal structures and organelles located locally in dendrites, play crucial roles in dendrite growth. By reviewing what has been unveiled to date regarding dendrite growth in terms of these local cellular components, we aim to provide an insight to categorize the potential cellular basis that can be applied to the dendrite pathology manifested in many neurodegenerative diseases.

Atomic-scale investigation of Epitaxial Graphene Grown on 6H-SiC(0001) Using Scanning Tunneling Microscopy and Spectroscopy

  • Lee, Han-Gil;Choe, Jeong-Heon;Kim, Se-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.125-125
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    • 2012
  • Graphene was epitaxially grown on a 6H-SiC(0001) substrate by thermal decomposition of SiC under ultrahigh vacuum conditions. Using scanning tunneling microscopy (STM), we monitored the evolution of the graphene growth as a function of the temperature. We found that the evaporation of Si occurred dominantly from the corner of the step rather than on the terrace. A carbon-rich $(6{\sqrt{3}}{\times}6{\sqrt{3}})R30^{\circ}$ layer, monolayer graphene, and bilayer graphene were identified by measuring the roughness, step height, and atomic structures. Defect structures such as nanotubes and scattering defects on the monolayer graphene are also discussed. Furthermore, we confirmed that the Dirac points (ED) of the monolayer and bilayer graphene were clearly resolved by scanning tunneling spectroscopy (STS).

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Exploring Fine Structures of Photoactive Yellow Protein in Solution Using Wide-Angle X-ray Scattering

  • Kim, Tae-Kyu;Zuo, Xiaobing;Tiede, David M.;Ihee, Hyot-Cherl
    • Bulletin of the Korean Chemical Society
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    • v.25 no.11
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    • pp.1676-1680
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    • 2004
  • We demonstrate that wide-angle X-ray scattering pattern from photoactive yellow protein (PYP) in solution using a high flux third generation synchrotron X-ray source reflects not only the overall structure, but also fine structures of the protein. X-ray scattering data from PYP in solution have been collected in q ranges from 0.02 ${\AA}^{-1}$ to 2.8 ${\AA}^{-1}$. These data are sensitive to the protein structure and consistent with the calculation based on known crystallographic atomic coordinates. Theoretical scattering patterns were also calculated for the intermediates during the photocycle of PYP to estimate the feasibility of time-resolved wide-angle X-ray scattering experiments on such proteins. These results demonstrate the possibility of using the wide-angle solution X-ray scattering as a quantitative monitor of photo-induced structural changes in PYP.

Correlation between the Reactant Complex or Transition State Conformations and the Reactivity of 4-Nitrophenyl Benzoate and Its Sulfur Analoguew with Anoinic Nucleophiles by Comparative Molecular Field Analysis (CoMFA)

  • 유성은;차옥자
    • Bulletin of the Korean Chemical Society
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    • v.17 no.7
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    • pp.653-655
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    • 1996
  • A comparative molecular field analysis (CoMFA) was carried out for the correlation of the transition state structures and the reaction rates for the SN2 reaction of 4-nitrophenyl benzoate and its sulfur analogs with anionic nucleophiles. The CoMFA analysis showed that both steric and electrostatic effects are important, and the steric contribution increased when nucleophiles are alkoxides or arylsulfides. In this study, we have demonstrated that the CoMFA analysis can be expanded beyond the scope of dealing with reactants and products. The reactant complex and transition state conformations generated along the reaction path can be more appropriately used for the correlation of structures and reaction rates.

Assessment of the Intermolecular π-π Configurations of Poly(3-Hexylthiophene) using Polarized Raman Spectroscopy

  • Juwon Kim;Myeongkee Park
    • Journal of the Korean Chemical Society
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    • v.68 no.3
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    • pp.146-150
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    • 2024
  • Precise molecular configuration elucidation of poly(3-hexylthiophene) (P3HT) through advanced spectroscopic techniques is pivotal for enhancing P3HT-based photovoltaic device efficiencies since its high charge-carrier mobility is directly correlated to its well-ordered structure. In this study, we examine Raman depolarization ratios of annealed and non-annealed P3HT films to elucidate their intermolecular π-π configurations. Our findings suggest that the backbone of the annealed film possesses stronger π-π conjugation overlaps than that of the non-annealed film owing to the greater depolarization ratio of the annealed film. In addition, the depolarization ratios are also supported by theoretical calculations, where parallel-stacked thiophene structures display a higher depolarization ratio compared with that of twisted-stacked structures, as calculated by the Møller-Plesset perturbation theory. This study highlights the utility of polarized Raman spectroscopy as a versatile tool for assessing the degree of molecular order in highly conjugated polymer films.

3D epigenomics and 3D epigenopathies

  • Kyung-Hwan Lee;Jungyu Kim;Ji Hun Kim
    • BMB Reports
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    • v.57 no.5
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    • pp.216-231
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    • 2024
  • Mammalian genomes are intricately compacted to form sophisticated 3-dimensional structures within the tiny nucleus, so called 3D genome folding. Despite their shapes reminiscent of an entangled yarn, the rapid development of molecular and next-generation sequencing technologies (NGS) has revealed that mammalian genomes are highly organized in a hierarchical order that delicately affects transcription activities. An increasing amount of evidence suggests that 3D genome folding is implicated in diseases, giving us a clue on how to identify novel therapeutic approaches. In this review, we will study what 3D genome folding means in epigenetics, what types of 3D genome structures there are, how they are formed, and how the technologies have developed to explore them. We will also discuss the pathological implications of 3D genome folding. Finally, we will discuss how to leverage 3D genome folding and engineering for future studies.

Na Borosilicate Glass Surface Structures: A Classical Molecular Dynamics Simulations Study (소듐붕규산염 유리의 표면 구조에 대한 분자 동역학 시뮬레이션 연구)

  • Kwon, Kideok D.;Criscenti, Louise J.
    • Journal of the Mineralogical Society of Korea
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    • v.26 no.2
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    • pp.119-127
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    • 2013
  • Borosilicate glass dissolution is an important chemical process that impacts the glass durability as nuclear waste form that may be used for high-level radioactive waste disposal. Experiments reported that the glass dissolution rates are strongly dependent on the bulk composition. Because some relationship exists between glass composition and molecular-structure distribution (e.g., non-bridging oxygen content of $SiO_4$ unit and averaged coordination number of B), the composition-dependent dissolution rates are attributed to the bulk structural changes corresponding to the compositional variation. We examined Na borosilicate glass structures by performing classical molecular dynamics (MD) simulations for four different chemical compositions ($xNa_2O{\cdot}B_2O_3{\cdot}ySiO_2$). Our MD simulations demonstrate that glass surfaces have significantly different chemical compositions and structures from the bulk glasses. Because glass surfaces forming an interface with solution are most likely the first dissolution-reaction occurring areas, the current MD result simply that composition-dependent glass dissolution behaviors should be understood by surface structural change upon the chemical composition change.