• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.314-320
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• 1999

Several bisphosphine- and bisphosphite-substituted Re-imido complexes have been prepared from Re(NPh)(PPh3)2Cl3, 1, and Re(N-C6H3-i-Pr2)2Cl3(py), 4. Compound 1 reacted with trimethyl phosphate (P(OMe)3) to give a mixture of two isomers,mer,trans-Re(NPh)(P(OMe)3)2Cl3, 2, and fac,cis-Re(NPh)(P(OMe)3)2Cl3, 2a. In this reaction, the mer,trans-isomer is a major product. Complex 1 also reacted with triethylphosphine (PEt3) to exclusively give mertrans-Re(NPh)(PEt3)2Cl3, 3. Compound 4 reacted with trimethylphosphine (PMe3) to give mer,trans-Re(N-C6H3-i-Pr2)(PMe3)2Cl3, 5, which was converted to mer-Re(N-C6H3-i-Pr2)(PMe)(OPMe3)Cl3, 6, on exposure to air. Crystallographic data for 2: monoclinic space group P21/n, a = 8.870(2) Å, b = 14.393(3) Å, c = 17.114(4) Å, β = 101.43(2)°, Z = 4, R(wR2) = 0.0521(0.1293). Crystallographic data for 5: orthorhombic space group P212121, a = 11.307(l) Å, b = 11.802(l) Å, c = 19.193(2) Å, Z = 4, R(wR2) = 0.0250(0.0593). Crystallographic data for 6: orthorhombic space group P212121, a = 14.036(4) Å, b = 16.486(5) Å, c = 11.397(3) Å, Z = 4, R(wR2) = 0.0261(0.0630).

• Korean Journal of Veterinary Service
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• v.28 no.4
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• pp.393-405
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• 2005

In prion pathogenesis, the structural conversion of the cellular prion protein $(PrP^c)$ to its abnormal isomer $(PrP^{Sc})$ is believed to be a major event. The susceptibility or resistance to natural sheep scrapie is associated with polymorphisms of host PrP gene (PRNP) at amino acid residues 136, to a lesser extent 154. The 112 residue in ovine PrP displays a natural polymorphism, Methionine to Threonine, which has not been thoroughly investigated. However the cell-free conversion assay showed that ARQ with Thr112 $(T_{112}ARQ)^{1)}$ presents lower convertibility to $PrP^{Sc}$than wild type ARQ $(M_{112}ARQ)$ [1] In this study we generated ovine recombinant PrPs of 112 allelic variants by metal chelate affinity chromatography and cation exchange chromatography. The final purity of the ovine PrP ARQ was more than $95\%$. These variants showed similar immunoreactivity against anti-PrP monoclonal antibodies in Western blot and ELISA. The refolded $M_{112}ARQ$ and $M_{112}ARQ$ presented the secondary structural content to similar extent via CD spectroscopy analysis. The inherited structural features of $M_{112}ARQ$ and $M_{112}ARQ$ under the different biophysical conditions are in the middle of investigation.

• Korean Journal of Crystallography
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• v.10 no.2
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• pp.105-109
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• 1999

Ar 기류 하에서 Re(N-C6H3-2,6-i-Pr2)2Cl3(py) (1)과 propionaldehyde (C2H5CHO)가 반응하여 생성된 혼합물에서, [cis-ReCl4(py)(N-C6H3-2,6-i-Pr2)·(NH2-C6H3-2,6-i-Pr2)] (2)가 분리되었다. 이 화합물의 구조가 X-ray 회절법으로 규명되었다. 착물 2의 결정학 자료: 단사정계 공간군 P21/n, a=11.555(1) Å, b=27.066(3) Å, c=11.881(1) Å, β=117.991(8)°, Z=4, R(wR2)=0.0332(0.0851.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.417-421
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• 2004

A normal prion protein (PrPc) is converted to a protease resistant isoform (PrPsc) by an apparent self-propagating activity in bovine spongiform encephalopathies (BSE), which is a neurodegenerative disease. The cDNA encoding bovine PrP open reading frame (ORP) in Korean cattle was cloned by polymerase chain reaction (PCR). The cloned cDNA had a length of 795 base pairs which coded for a protein of 264 amino acid residues with a calculated molecular mass of 28.6 kDa. Identities of 90, 90, 79 and 78% on nucleotide and 94, 94, 84, and 84% on amino acid sequence were shown to PrP genes from sheep, goat, human, and mouse, respectively. The cloned DNA was ligated into the pQE30 expression vector and transformed into E. coli M15. The PrP was expressed by induction with isopropyl-$\beta$-D-thiogalactoside (IPTG) and purified on the Ni-NTA affinity column. High specific activities of the recombinant PrP were observed in the fraction of pH 5.8 eluate and showed a molecular mass of-29 kDa on SDS-PAGE and Western blot analysis.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.90-96
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• 2004

The conformations of dicyclopropyl, isopropyl cyclopropyl, and diisopropylcarbenes were optimized using density functional theory (B3LYP/6-31G(d)). We showed that the optimized geometries of carbenes with cyclopropyl groups are fully in accord with those expected for bisected W-shaped conformations, in which the effective hyperconjugation of a cyclopropyl group with singlet carbene can occur. The stabilization energies were evaluated at the B3LYP/6-311+G(3df, 2p)//B3LYP/6-31G(d) + ZPE level using an isodesmic equation. The relative stability of carbenes is in the order $(c-Pr)_2$C: > (i-Pr)(c-Pr)C: > $(i-Pr)_2$C:, and a cyclopropyl group stabilizes carbene more than an isopropyl group by nearly 9 kcal/mol. Energies for the decomposition of diazo compounds to carbenes increase in the order $(c-Pr)_2$ < (i-Pr)(c-Pr) < $(i-Pr)_2$ by ~9 kcal/mol each. From a singlettriplet energy gap ($E_{ST}$) calculation, the singlet level is lower than the triplet level and the $E_{ST}$ shows a trend similar to the stabilization energy calculations. For comparison, the optimized geometries and stabilization energies for the corresponding carbocations were also studied at the same level of calculation. The greater changes in geometries and the higher stabilization energies for carbocations compared to carbenes can explain the greater hyperconjugation effect.

• Molecules and Cells
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• v.27 no.6
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• pp.673-680
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• 2009

Conversion of the normal soluble form of prion protein, PrP ($PrP^C$), to proteinase K-resistant form ($PrP^{Sc}$) is a common molecular etiology of prion diseases. Proteinase K-resistance is attributed to a drastic conformational change from ${\alpha}$-helix to ${\beta}$-sheet and subsequent fibril formation. Compelling evidence suggests that membranes play a role in the conformational conversion of PrP. However, biophysical mechanisms underlying the conformational changes of PrP and membrane binding are still elusive. Recently, we demonstrated that the putative transmembrane domain (TMD; residues 111-135) of Syrian hamster PrP penetrates into the membrane upon the reduction of the conserved disulfide bond of PrP. To understand the mechanism underlying the membrane insertion of the TMD, here we explored changes in conformation and membrane binding abilities of PrP using wild type and cysteine-free mutant. We show that the reduction of the disulfide bond of PrP removes motional restriction of the TMD, which might, in turn, expose the TMD into solvent. The released TMD then penetrates into the membrane. We suggest that the disulfide bond regulates the membrane binding mode of PrP by controlling the motional freedom of the TMD.

• Korean Journal of Crystallography
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• v.12 no.3
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• pp.137-140
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• 2001

Compound PdCl₂(Phc≡N)₂(1) reacted with 2,6-diisopropylaniline to give trans-[Pd(NH₂-C/sub 6/-H₃-2, 6-i-Pr₂)₂Cl₂] (2). Compound 2 was characterized by spectroscopy (¹H-NMR, /sup 13/C-NMR, and IR) and X-ray diffraction. Crystallographic data for 2: monoclinic space group P2₁/n, a=13.532(3) Å, b=5.749(1) Å, c=17.880(4)Å, β=103.84(2)°, Z=2, R(wR₂)=0.0466(0.1226).

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.10-15
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• 2000

Compound trans-[FeH(NCS(i-Pr)-S)(dppe)₂](1) reacted with isopropyl iodide (i-PrI) to give an Fe(II)-organic isothiocyanide complex, trans-[FeH(NCS(i-Pr)-S)(dppe)₂]I (2). Compound 2 was structurally characterized, in which the hydride ligand appears to be involved in the "dihydrogen" bonding, M-H…H-C. Crystallographic data for 2: monoclinic space group P2₁/n, a=13.490(2)Å, b=17.269(3)Å, c=21.384(3)Å, β=90.682(7)°, Z=4, R(wR₂)=0.0348(0.0894).

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.138-142
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• 1996

The transition metal carbonylate, PPN+(${\eta}^5-MeCp)Mn(CO)_2Cl^-$ undergoes a novel ligand substitution reaction with PR3 (R=Me, Et, OEt, $C_6H_5$ in THF at elevated temperatures (40 $^{\circ}C$ up to 60 $^{\circ}C)$ under the pseudo-first-order reaction conditions (usually 20-fold excess of PR3 with respect to metal carbonylate concentrations) where chloride is displaced by PR3. The reaction follows overall first order dependence on [(${\eta}^5-MeCp)Mn(CO)_2Cl^-$]; however, the negative entropy changes of activation (${\Delta}S^{\neq}$=-19.3 e.u. for $P(OEt)_3$; ${\Delta}S^{\neq}$=-16.4 e.u. for $PPh_3$) suggest the existence of the intermediate, ((η3-MeCp)Mn(CO)2(THF)Cl-, which eventually transforms to the product (${\eta}^5-MeCp)Mn(CO)_2(PR_3)$.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.2
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• pp.130-135
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• 2003

The Characteristics of dough and the quality of baguette with 1~5% pigmented rice(PR) were investigated. The pH of dough with PR were lower(pH 4.93~5.06) than that of the control(pH 5.13). The viscosity of dough with PR(498~575 BU) measured by the amylograph were lower than that of the control(600 BU). The volume of the baguette with PR(1~3%) was higher than that of the control. Color $L^{*}$ value of baguette crumb with PR decreased from 60.65 to 50.44~60.36 and color $a^{*}$ value increased from -2.13 to 0.28~3.30 as the concentration of PR increased. The hardness of the baguette decreased from 375.51$\times$10$^4$dyne/c $m^2$to 273.95~256.83$\times$10$^4$dyne/c $m^2$as the concentration of PR increased. The overall acceptability score of baguette was the highest with 3% PR.R.R.