• Korean Journal of Crystallography
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• v.4 no.1
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• pp.6-10
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• 1993

11 β ,17 β -dihydroxy-9a-fluoro-l7a-methyl androst-4-en-3-one (Fluoxymesterone), CgoH29 FO,, orthorhombic, P2,2,2,, a=13.468(5) A, b= 19.554 (2)A, c=6.578(9)A, a=b=r=90˚, A (CuKa)=1.5406 A , Dm=1.289cm-3, Dc=1.299cm-3 and Z=4 at T=298k. The structure was solved by direct method using seminvariants of ggg Parity group and refined by the full-matrix least-square method, resulting model with reliability factor R=0.069 for 1098 unique reflection over 3σ . Ring A is an 1β-2a-half chair, 5 ring has a highly symmetrical chair conformation, C ring is in a distorted chair conformation and D ring is a 13aenveLope conformation. In the crystal structure, the molecules are packed with a hydrogen bond of 011-H23‥‥03(0.5+x, 1.5-y, 1.0-z) [1.94(9) A of H‥‥0.2.786(9)A of 0‥‥0 and 165(8) ˚ of

• Journal of Photoscience
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• v.1 no.1
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• pp.31-37
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• 1994

Photoirradiation at > 300 nm onto a suspension of platinized TiO$_2$ (TiO$_2$-Pt) particles in an aqueous solution. of N$_{\varepsilon}$-carbamyI-L-lysine (Lys(CONH)$_2$) induced the selective N-cyclization of Lys(CONH$_2$) into almost optically pure L-pipecolinic acid (PCA) under argon atmosphere at ambient temperature. Among various TiO$_2$-Pt catalysts, a P-25 (Degussa) powder platinized via impregnation from chloroplatinic acid followed by hydrogen reduction at 753 K exhibited the highest photocatalytic activity for Lys(CONH$_2$) consumption and L-PCA production. GC-MS analyses of L-PCA obtained photocatalytically from $^{15}$N$\alpha$-Lys(CONH$_2$) revealed the selective formation $^{15}$N-substituted L-PCA. This implies that the mechanism for L-PCA production contains selective cleavage of C$_{\varepsilon}$-N bond and intramolecular alkylation at $\alpha$-amino group. Effect of pH on the rate of this photocatalytic reaction was investigated in detail and compared with the pH-dependent charge distribution in Lys(CONH$_2$) molecule. It is clarified that protonation-deprotonation of $\alpha$-amino group gives marked influence on the rate and selectivity of the photocatalytic reaction. On the basis of these results, it is concluded that the selective production of optically pure L-PCA, especially in an acidic suspension of TiO$_2$-Pt, was attributed to the enhanced protonation of $\alpha$-amino group to prevent undesirable oxidation by photogenerated positive holes and blocking of $\varepsilon$-amino group to yield racemic Schiff base intermediate.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.326-330
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• 2005

In the catalytic hydrolysis of 2',3'-cAMP by the Cu(II) complexes of 2,9-(N,N-dimethylethylenediamino)-1,10-phenanthroline (A) and 2,9-(N,N-dimethylethylenediaminomethyl)-1,10-phenanthroline (B) that are designed as a new ligand molecule of artificial DNase, due to the four intramolecular H-bonds forming between amino groups of ligand molecule and phosphoryl group of 2',3'-cAMP. It is anticipated that Cu(II) complexes of (A) and (B) are able to promote a rate that is as much as seventy thousand times faster than the catalytic hydrolysis rate of 2',3'-cAMP by Cu(II) complexes of 2,9-dimethyl-o-phenanthroline.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1712-1716
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• 2007

To generate new scaffold candidates as highly selective and potent cyelin-dependent kinase (CDK) inhibitors, structure-based drug screening was performed utilizing 3D pharmacophore conformations of known potent inhibitors. As a result, CR229 (6-bromo-2,3,4,9-tetrahydro-carbolin-1-one) was generated as the hit-compound. A computational docking study using the X-ray crystallographic structure of CDK2 in complex with CR229 was evaluated. This predicted binding mode study of CR229 with CDK2 demonstrated that CR229 interacted effectively with the Leu83 and Glu81 residues in the ATP-binding pocket of CDK2 for the possible hydrogen bond formation. Furthermore, biochemical studies on inhibitory effects of CR229 on various kinases in the human cervical cancer HeLa cells demonstrated that CR229 was a potent inhibitor of CDK2 ($IC_{50}:\;3\;{\mu}M$), CDKI ($IC_{50}:\;4.9\;{\mu}M$), and CDK4 ($IC_{50}:\;3\;{\mu}M$), yet had much less inhibitory effect ($IC_{50}:>20\;{\mu}M$) on other kinases, such as casein kinase 2-${\alpha}1$ (CK2-${\alpha}1$), protein kinase A (PKA), and protein kinase C (PKC). Accordingly, these data demonstrate that CR229 is a potent CDK inhibitor with anticancer efficacy.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.145-153
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• 2018

Among the carotenoid biosynthesis genes, crtI gene encodes the phytoene desaturase (CrtI) enzyme, and phytoene desaturase convert phytoene to lycopene. Phytoene desaturase is involved in the dehydrogenation reaction, in which four single bonds in the phytoene are introduced into a double bond, eliminating eight hydrogen atoms in the process. Phytoene desaturase is one of the key regulating enzyme in carotenoid biosynthetic pathway of various carotenoid biosynthetic organisms. The crtI gene in genomic DNA of Paracoccus haeundaensis was amplified and cloned into a T-vector to analyze the nucleotide sequence. As a result, the crtI gene coding for phytoene desaturase from P. haeundaensis consists of 1,503 base pairs encoding 501 amino acids residues. An expression plasmid containing the crtI gene was constructed, and Escherichia coli cells containing this plasmid produced the recombinant protein of approximately 55 kDa, equivalent to the molecular weight of phytoene desaturase. The expressed protein in cell lysate showed enzymatic activity similar to phytoene desaturase. Phytoene and lycopene were analyzed by HPLC and measured at wavelength of 280 nm and 470 nm, respectively. The $K_m$ values for phytoene and NADPH were $11.1{\mu}M$ and $129.3{\mu}M$, respectively.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.180-188
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• 1974

Adsorption mechanism of alkyl aldehydes, acetaldehyde, acrolein, and crotonaldehyde on cations supported by layer silicates was studied by means of IR spectroscopy and X-ray. An analysis of four characteristic split bands in the region of $1720∼1580㎝^{-1}$ was made. The carbonyl stretching band which shifted about $130㎝^{-1}$ to lower frequencies was observed only for $Ni^{2+}$ and Al^{3+}$ but slightly with $Ca^{2+}$ at high sample temperature and was attributed to >C=O…M complex formation. A sharp band which appeared as a shoulder at 1722 for acetaldehyde and 1690 for acrolein and crotonaldehyde was responsible for the interaction of carbonyl with surface hydroxyl. The second broad band which appeared at about 1710~1660 was responsible for hydrogen bonding between carbonyl oxygen and cationic hydroxyl group. The third band which appeared at about 1640~1660 was attributed to induced >C=C< double bond due to the strong carbonyl interaction. This was supported by the interlamellar spacings obtained by X-ray diffractometry.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.810-814
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• 2013

The thermodynamic parameters for the intercalative interaction of structurally related well known intercalators, 9-aminoacridine (9AA) and proflavine (PF) were determined by means of fluorescence quenching study. The fluorescence intensity of 9AA decreased upon intercalation to DNA, poly[$d(A-T)_2$] and poly[$d(G-C)_2$]. A van't Hoff plot was constructed from the temperature-dependence of slope of the ratio of the fluorophore in the absence and presence of a quencher molecule with respect to the quencher concentration, which is known as a Stern-Volmer plot. Consequently, the thermodynamic parameters, enthalpy and entropy change, for complex formation was calculated from the slope and y-intercept of the van't Hoff plot. The detailed thermodynamic profile has been elucidated the exothermic nature of complex formation. The complex formation of 9AA with DNA, poly[$d(A-T)_2$] and poly[$d(G-C)_2$] was energetically favorable with a similar negative Gibb's free energy. On the other hand, the entropy change appeared to be unfavorable for 9AA-poly[$d(G-C)_2$] complex formation, which was in contrast to that observed with native DNA and poly[$d(A-T)_2$] cases. The equilibrium constant for the intercalation of PF to poly[$d(G-C)_2$] was larger than that to DNA, and was the largest among sets tested despite the most unfavorable entropy change, which was compensated for by the largest favorable enthalpy. The favorable hydrogen bond contribution to the formation of the complexes was revealed from the analyzed thermodynamic data.

• Molecules and Cells
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• v.37 no.2
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• pp.100-108
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• 2014

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu,Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

• Journal of the Korean Chemical Society
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• v.28 no.4
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• pp.205-209
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• 1984

The crystal and molecular structure of thiosinamine, $H_2NCSNHCH_2CHCH_2$, has been determined by X-ray diffraction method. The crystals are monoclinic, space group $P2_1/a$ with four molecules in a unit cell of dimensions, a = 9.819(3), b = 8.553(3), c = 9.170(2)${\AA}$, ${\beta}$ = 127.3(1)$^{\circ}$, and z = 4. Intensity data for 814 reflections were collected with a Rigaku-Denki automatic four circle diffractometer. The structure was solved by direct and Fourier methods. Refinements were carried out by full matrix least-squares method to a final R value of 0.046. The thiourea unit is planar, and the bond lengths and angles in that unit agree well with those in the compounds which contain a thiourea moiety. The molecules are linked together by the two patterns of N-H${\cdots}$S hydrogen bonds along the b-axis.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2086-2092
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• 2014

Two novel coordination compounds $[Cu_2(pypya)_3(H_2O)_2]{\cdot}Cl{\cdot}(H_2O)_5$ (1) and $\{[Cd(pypya)(ta)_{1/2}]{\cdot}H_2O\}_n$ (2) (Hpypya=2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetic acid, $H_2ta$=terephthalic acid) were synthesized and characterized by single X-ray diffraction. Structure determination reveals that complex 1 and complex 2 crystallize in the triclinic system, with the P-1 space group. The asymmetric unit of 1 contains two Cu(II) ions, and their coordination modes are different. These units of complex 1 are linked together via hydrogen bonds and ${\pi}-{\pi}$ interactions, and the 3D structure of complex 1 was formed. Complex 2, a mononuclear Cd(II) coordination compound, has a 2D structure which was constructed via coordination bonds. TGA and fluorescence spectra analysis of complex 1 and complex 2 have also been studied. In addition, the geometry parameters of complex 1 have been optimized with the B3LYP method of density functional theory (DFT) to explain its coordination behavior. The electronic properties of the complex 1 and ligand Hpypya have been investigated based on the nature bond orbital (NBO) analysis at the B3LYP level of theory. The result verifies that the synergistic effect have occurred in the compound.