• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.959-964
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• 2007

The benzene complexes with dimethyl sulfur (DMS) and fluorinated DMS (FDMS) have been investigated using ab initio calculations. The natural bond orbital (NBO) charge population on S atom varies remarkably for different conformations of DMS and FDMS, which determines the possible binding modes for their benzene complexes. The electronegative substituent at the methyl group of DMS causes a significant change in the molecular electrostatic potential around the sulfur atom and changes the interaction mode with aromatic ring. It was found that the sulfur…π interaction mode does not occur in the DMS-benzene complex, while it does in the FDMS-benzene complex. Both B3LYP and MP2 methods provide reliable structures, while the interaction energy obtained by B3LYP is unreliable.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2930-2936
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• 2012

A three-dimensional pharmacophore hypothesis was developed for atypical antipsychotics in order to map common structural features of highly active compounds by using HipHop in CATALYST program. The pharmacophore hypotheses were generated using 12 compounds as training set and validated using 11 compounds as test set. The most predictive hypothesis (Hypo1) comprises five features viz. two hydrophobic regions, two hydrogen bond acceptor lipid and one aromatic ring. In the absence of information like crystallized structure of 5-$HT_{2A}$ receptor and binding mode of antipsychotics with 5-$HT_{2A}$ receptor, this hypothesis will serve as a potentially valuable tool in the design of novel atypical antipsychotics acting primarily at 5-$HT_{2A}$ and $D_2$ receptors.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.695-702
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• 2003

Recent experimental and theoretical advances on the aromatic alcohol-water clusters are reviewed, focusing on the structure of the hydrogen bonding between the alcoholic OH group and the binding water molecules. The interplay of experimental observations and theoretical calculations for the elucidation of the structure is demonstrated for phenol-water, benzyl alcohol-water, substituted phenol-water, naphthol-water and tropolone -water clusters. Discussion is made on assigning the role (either proton-donating or -accepting) of the hydroxyl group by measuring the shifts of infrared frequency of the OH stretching mode in the cluster from that of bare aromatic alcohol for the experimental determination of the cluster structure.

• Journal of Integrative Natural Science
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• v.8 no.4
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• pp.267-272
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• 2015

Galactosemia is a potentially lethal disorder caused by the deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT) within the Leloir pathway. Galactokinase (GALK) is the enzyme in Leloir pathway which converts ${\alpha}$-D galactose to galactose 1-phosphate. The elevated level of galactose-1-phosphate, the product of GALK plays a major role in Galactosemia. Therefore the inhibition of GALK is a novel therapy for this disorder. Hence in the present study, we performed molecular docking of twenty inhibitors with different activity against galactokinase into the active site of galactokinase enzyme. The binding mode of these inhibitors was obtained using Surflex dock program interfaced in Sybyl-X2.0. The residues such as SER141, TYR109, ARG105, ARG228, TYR106, GLY346, GLY136, ASP86, ASP186 and SER142 found to interact with inhibitors.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2369-2376
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• 2007

N2O has been found from experimental and theoretical considerations to bind on-top to the Pd(110) surface in a tilted end-on fashion via its terminal N atom. We use a frontier orbital description of the bonding interactions in the Pd-N2O system to obtain molecular insight into the catalytic mechanism of the activation of N2O by the Pd(110) surface giving rise to the formation of N2 and O on the surface. For the tilted end-on N2O binding mode, the LUMO 3π of N2O has good overlap with the Pd dσ and dπ orbitals which can serve as the electron donors. The donor-acceptor orbital overlap is favorable for electron transfer from Pd to N2O and is expected to dominate the surface reaction pathway of N2O decomposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.42-45
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• 2004

High quality CdTe single crystal for the solar cell fabrication was grown by vertical Bridgman method. The etch pits patterns of {111}surfaces of CdTe etched by Nakagawa solution was observed the {111} A composed of Cd atoms with typical triangle etch pits of pyramid mode. From the photoluminescence measurement on {111}A, we observed free exciton($E_x$) existing only higy quality crystal and neytral acceptor bound exciton($A^0$,X) having very strong peak intensity. Then, the full width at half maximum and binding energy of neutral acceptor bound exciton were 7 meV and 5.9 meV, respectively. By Haynes rule, an actibation energy of impurity was 59 meV. Therefore, the origins on impurity level acting as a neutral acceptor were associated Ag or Cu elements.

• Proceedings of the Korean Society of Life Science Conference
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• 2003.05a
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• pp.23-37
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• 2003

A novel inhibitor against maltose-producing a-amylase was prepared via stepwise degradation of a high molecular weight acarbose (HMWA) using Thermus maltogenic amylase (ThMA). The structure of the purified inhibitor was determined to be ${\alpha}$-D-glucopyranosyl-${\alpha}$-acarviosinyl-D-glucopyranose (GlcAcvGlc). Progress curves of p-nitrophenyl-${\alpha}$-D-maltoside (PNPG2) hydrolysis by various amylolytic enzymes, including maltogenase (MGase), ThMA, and cyclodextrinase(CDase) I-5, in the presence of acarbose or GlcAcvGlc indicated a slow-binding mode of inhibition. The inhibition potency of GlcAcvGlc for MGase, ThMA, and CDase I-5 was 3 orders of magnitude higher than that of acarbose.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.212-216
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• 2015

Oseltamivir, also known as Tamifu, is an inhibitor of neuraminidase protein which plays an essential role in proliferation and replication of influenza virus. Binding to the active site of neuraminidase, the oseltamivir prevents the protein from enzyme reaction. Conformational change of the protein(neuraminidase) should be accompanied by the enzyme reaction, but the drug inhibits the protein to deform. In this study, we examine the influence of oseltamivir on protein's conformational change in the structural and mechanical point of view. Finite element analysis of the protein can be an useful approach to investigate the influence of oseltamivir on the deformation of a protein. We suggest the finite element based protein model, and then perform the linear static analysis with the displacement loading condition based on the first two largest motion which can be obtained from the normal mode analysis. The results show that it takes more energy to change shape of the protein with an oseltamivir attached than the protein without an oseltamivir.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.821-828
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• 2011

Design and synthesis of new 3,4-diarylpyrazole-1-carboxamide derivatives are described. Their antiproliferative activity against A375 human melanoma cell line was tested and the effect of substituents on the diarylpyrazole scaffold was investigated. The pharmacological results indicated that most of the synthesized compounds showed moderate activity against A375, compared with Sorafenib. On the other hand, compounds Ia, Ie, IIb, and IIh were more potent than Sorafenib. In addition, compound IIa was equipotent to Sorafenib. Among all of these derivatives, compound IIb which has diethylamino and phenolic moieties showed the most potent antiproliferative activity against A375 human melanoma cell line. Virtual screening was carried out through docking of the most potent compound IIb into the domain of V600E-b-Raf and the binding mode was studied.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.725-729
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• 2007

We present calculations for the acetonitrile - water clusters to examine the nature of interactions in the mixed clusters. We calculate conformers of various composition, either of σ -type (-OH and -CN binding linearly) or π -type (-OH and -CN interacting perpendicularly) structures for the acetonitrile - water clusters. We predict that the IR frequency of the proton-accepting C≡N stretching mode red-shifts in the σ -type clusters and blueshifts in π -type conformers, whereas the proton-donating ?OH stretching frequency red-shifts in all cases. We find that this intriguing pattern also applies to the acetonitrile - water clusters of various molar ratio.