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Search Results: 1 - 10 of 6150 matches for " Woo Sung Son "
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Structural Analysis of Hypothetical Proteins from Helicobacter pylori: An Approach to Estimate Functions of Unknown or Hypothetical Proteins
Sung Jean Park,Woo Sung Son,Bong-Jin Lee
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13067109
Abstract: Helicobacter pylori ( H. pylori) have a unique ability to survive in extreme acidic environments and to colonize the gastric mucosa. It can cause diverse gastric diseases such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, gastric cancer, etc. Based on genomic research of H. pylori, over 1600 genes have been functionally identified so far. However, H. pylori possess some genes that are uncharacterized since: (i) the gene sequences are quite new; (ii) the function of genes have not been characterized in any other bacterial systems; and (iii) sometimes, the protein that is classified into a known protein based on the sequence homology shows some functional ambiguity, which raises questions about the function of the protein produced in H. pylori. Thus, there are still a lot of genes to be biologically or biochemically characterized to understand the whole picture of gene functions in the bacteria. In this regard, knowledge on the 3D structure of a protein, especially unknown or hypothetical protein, is frequently useful to elucidate the structure-function relationship of the uncharacterized gene product. That is, a structural comparison with known proteins provides valuable information to help predict the cellular functions of hypothetical proteins. Here, we show the 3D structures of some hypothetical proteins determined by NMR spectroscopy and X-ray crystallography as a part of the structural genomics of H. pylori. In addition, we show some successful approaches of elucidating the function of unknown proteins based on their structural information.
Structural studies on the antimicrobial peptide Brevinin 1E by spectroscopic methods
Woo-Sung Son,Ji-Sun Kim,Hyung-Eun Kim,Sang-Ho Park,Bong-Jin Lee
Spectroscopy: An International Journal , 2003, DOI: 10.1155/2003/650369
Abstract: Skin extracts of frogs are a rich source of pharmacologically active peptides such as caeruleins, tachykinins, bradykinins, thyrotropin-releasing hormone, bombesin-like and opioid peptides. A large variety of antimicrobial peptides has been isolated from Rana species. These peptides, grouped in several families on the basis of differing length and distinct activity, were found to have one structural motif in common: an intramolecular disulfide bridge located at the C-terminal end, forming a seven-member ring, which was designated ‘Rana box’. Brevinin 1E is a 24-residue antimicrobial peptide isolated from the skin of a frog, Rana brevipoda. This peptide shows a broad range of antimicrobial activity against prokaryotic cells but shows very much hemolytic activity against human red blood cells. The solution structure of Brevinin 1E was studied by using CD (circular dichroism) and NMR (nuclear magnetic resonance) spectroscopy. CD investigation revealed that Brevinin 1E adopts random structure in aqueous solution but adopts mainly α-helical structure in TFE/water (6?: 4, v/v) solution. The three-dimensional structure of Brevinin 1E was determined in 60% TFE/water solution using homonuclear NMR spectroscopy. This peptide showed mainly an α-helical structure with amphipathic property. Its three-dimensional structure is similar to those of other peptides such as magainin, nigrocin and ranalexin. Therefore, Brevinin 1E can be classified into the family of antimicrobial peptides containing a single linear α-helix that interact with target microbial membrane, leading to cell death through disruption of membrane integrity.
Intraplate Strike-Slip Reactivation of the Sinnyeong Fault in the Cretaceous Gyeongsang Basin, Korea, Due to the Concentration of Later Compressional Stress  [PDF]
Youngbeom Cheon, Cheol Woo Song, Son Kap Lee, Jong-Sun Kim, Moon Son
Journal of Geoscience and Environment Protection (GEP) , 2013, DOI: 10.4236/gep.2013.13003
Abstract:

This study focuses on the geometry and kinematics of the Sinnyeong Fault which is the most conspicuous fault among the WNW-trending Gaeum Fault System in the Gyeongsang Basin,SE Korea. The fault is traced for over ca.70 kmand has a consistent WNW-trending strike with a nearly vertical dip. It has an asymmetric fault damage zone of several meters to several tens of meters in width and a several meter-thick fault core. Its main movement is interpreted as sinistral-reverse oblique-slip or sinistral strike-slip under NE-SW compressional stress regime, although it could have experienced other faultings with different senses before/after this movement. Cylindrical folds, having the NW-trending fold axes of low angle plunge, are only observed along the southern damage zone of the fault with a continuous narrow width of several tens of meters. It is thus interpreted that the formation of the folds and sinistral movement of the fault were almost contemporaneously generated due to the concentration of the regional NE-SW compressional stress along pre-existing WNW-trending faults or densely populated fracture zone in a relatively stable intraplate region.

Vortex Dynamics in an Annular Bose-Einstein Condensate
S. J. Woo,Young-Woo Son
Physics , 2012, DOI: 10.1103/PhysRevA.86.011604
Abstract: We theoretically show that the topology of a non-simply-connected annular atomic Bose-Einstein condensate enforces the inner surface waves to be always excited with outer surface excitations and that the inner surface modes are associated with induced vortex dipoles unlike the surface waves of a simply-connected one with vortex monopoles. Consequently, under stirring to drive an inner surface wave, a peculiar population oscillation between the inner and outer surface is generated regardless of annulus thickness. Moreover, a new vortex nucleation process by stirring is observed that can merge the inner vortex dipoles and outer vortex into a single vortex inside the annulus. The energy spectrum for a rotating annular condensate with a vortex at the center also reveals the distinct connection of the Tkachenko modes of a vortex lattice to its inner surface excitations.
Ideal Strength of Doped Graphene
S. J. Woo,Young-Woo Son
Physics , 2012, DOI: 10.1103/PhysRevB.87.075419
Abstract: While the mechanical distortions change the electronic properties of graphene significantly, the effects of electronic manipulation on its mechanical properties have not been known. Using first-principles calculation methods, we show that, when graphene expands isotropically under equibiaxial strain, both the electron and hole doping can maintain or improve its ideal strength slightly and enhance the critical breaking strain dramatically. Contrary to the isotropic expansions, the electron doping decreases the ideal strength as well as critical strain of uniaxially strained graphene while the hole doping increases the both. Distinct failure mechanisms depending on type of strains are shown to be origins of the different doping induced mechanical stabilities. Our findings may resolve a contradiction between recent experimental and theoretical results on the strength of graphene.
Recent advances in sow nutrition
Kim, Sung Woo;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001300033
Abstract: sows produce a larger number of fetuses than before and these fetuses possess genetic potentials to grow faster than before. recent comparison shows that a porcine fetus is 40% heavier than 40 years ago. thus the nutritional management of sows has been updated to reflect these genetic changes. our recent study quantified nutritional needs for sows to support the growth of fetuses and mammary glands during gestation. amino acid needs for fetal growth and mammary growth during late gestation (d 70 to farrowing) significantly greater than those needs during early gestation (until d 70). considering these increases, daily requirement of true ileal digestible lys for a primiparous sows increases from 7 g (until d 70) to 15 g (d 70 to farrowing). required qualities of proteins (i.e., amino acid ratios) also change with an advance of pregnancy as maternal, fetal, and mammary tissues have their unique amino acid compositions. thus, if the feed does not provide sufficient amounts and qualities of proteins, sows can be under a severe catabolic status during late gestation, especially during late gestation. sows under a conventional feeding program had increased litter weight variations at farrowing (19%) compared with early gestation (3.0%). our recent study also shows that sows under a conventional feeding program have a dramatic increase in a systemic oxidative stress during late gestation compared with early gestation when measured by plasma α-tocopherol (56% decrease), plasma retinol (57% decrease), and dna damage in white blood cells (125% increase) which were sustained until the early lactation period. increased oxidative damages in sows negatively affect the growth and health of fetuses as well as postpartum growth. sow feeding during late gestation should reflect the changed needs for amino acids and antioxidants. phase feeding or top dressing could be a practical solution to provide sufficient nutrients during late gestation.
Roles of cysteine residues in the inhibition of human glutamate dehydrogenase by palmitoyl-CoA
Sung-Woo Cho
BMB Reports , 2012,
Abstract: Human glutamate dehydrogenase isozymes (hGDH1 andhGDH2) have been known to be inhibited by palmitoyl-CoAwith a high affinity. In this study, we have performed the cassettemutagenesis at six different Cys residues (Cys59, Cys93,Cys119, Cys201, Cys274, and Cys323) to identify palmitoyl-CoA binding sites within hGDH2. Four cysteine residuesat positions of C59, C93, C201, or C274 may be involved, atleast in part, in the inhibition of hGDH2 by palmitoyl-CoA.There was a biphasic relationship, depending on the levels ofpalmitoyl-CoA, between the binding of palmitoyl-CoA and theloss of enzyme activity during the inactivation process. The inhibitionof hGDH2 by palmitoyl-CoA was not affected by theallosteric inhibitor GTP. Multiple mutagenesis studies on thehGDH2 are in progress to identify the amino acid residuesfully responsible for the inhibition by palmitoyl-CoA.
On positiveness and contractiveness of the integral operator arising from the beam deflection problem on elastic foundation
Sung Woo Choi
Mathematics , 2014,
Abstract: We provide a complete proof that there are no nontrivial eigenvalues of the integral operator $\mathcal{K}_l$ outside the interval $(0,1/k)$. $\mathcal{K}_l$ arises naturally from the deflection problem of a beam with length $l$ resting horizontally on an elastic foundation with spring constant $k$, while some vertical load is applied to the beam.
Decay Rate Ratios of Upsilon(5S) to B Bbar Reactions
Hwang, Dae Sung;Son, Hyungsuk
High Energy Physics - Phenomenology , 2008,
Abstract: We calculate the decay rate ratios for OZI allowed decays of Upsilon(5S) to two B mesons by using the decay amplitudes which incorporate the wave function of the Upsilon(5S) state. We obtain the results that the branching ratio of the Upsilon(5S) decay to Bs* Bs*bar is much larger than the branching ratio to Bs Bs*bar or Bsbar Bs*, in good agreement with recent experimental results of CLEO and BELLE. This agreement with the experimental results is made possible since the nodes of the Upsilon(5S) radial wave function induce the nodes of the decay amplitude. We find that the results for the Upsilon(5S) decays to Bu(*) Bu(*)bar or Bd(*) Bd(*)bar pairs are dependent on the parameter values used for the potential between heavy quarks.
X-ray Raman compression via two-stream instability in dense plasmas
S. Son,Sung Joon Moon
Physics , 2011, DOI: 10.1063/1.3554723
Abstract: A Raman compression scheme suitable for x-rays, where the Langmuir wave is created by an intense beam rather than the pondermotive potential between the seed and pump pulses, is proposed. The required intensity of the seed and pump pulses enabling the compression could be mitigated by more than a factor of 100, compared to conventionally available other Raman compression schemes. The relevant wavelength of x-rays ranges from 1 to 10 nm.
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