• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.117-132
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• 1994

New methodolgies for the syntheses of unsymmetrical squarylium(SQ) dyes for organic photoconductors(OPC) were developed and photostabilities for these dyes were dicucced. These dyes absorbed at 640-690nm and exhibit high molecular extinction coefficient about 10. photodegradation rate of these dyes is acceralated in the presence if singlet oxygen sensitizer. On the other hand, the photodegradation rate os retarded by adding effective singlet oxygen quencher, such as 2:1 metal dithiolate. It is suggested that the photodegration of unsymmetrical SQ dye may be due to a photo-oxidation involving singlet oxygen.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.2
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• pp.33-45
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• 1995

1, 4-Diketo-3, 6-diphenyl-pyrrolo-[3, 4c]-pyrrole(abbriviated DPP) is a new heterocyclic pigment of red color whose chlorinated derivative is now on the market. DDP was synthesized from benzonitrile and diethylsuccinate. Pariser-parr-pople(PPP) molecular orbital calculations have been carried out on the DPP in other to study spectroscopically the DPP chromophore on deprotonation.

• BMB Reports
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• v.42 no.11
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• pp.697-704
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• 2009

Membrane proteins play important roles in the biology of the cell, including intercellular communication and molecular transport. Their well-established importance notwithstanding, the high-resolution structures of membrane proteins remain elusive due to difficulties in protein expression, purification and crystallization. Thus, accurate prediction of membrane protein topology can increase the understanding of membrane protein function. Here, we provide a brief review of the diverse computational methods for predicting membrane protein structure and function, including recent progress and essential bioinformatics tools. Our hope is that this review will be instructive to users studying membrane protein biology in their choice of appropriate bioinformatics methods.

• Rapid Communication in Photoscience
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• v.3 no.2
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• pp.38-41
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• 2014

The title compound (BMBZA) was designed and synthesized as a novel fluorescent amorphous molecular material. BMBZA was found to exhibit solvatofluorochromism and to readily form an amorphous glass by cooling the melt on standing. In addition, the morphological change from crystalline state to amorphous one could be induced by mechanical grinding. Although fluorescence was scarcely observed for the crystalline sample of BMBZA, the grinding the sample was found to enhance the fluorescence emission, that is, BMBZA exhibited on-off type mechanofluorochromism.

• Molecules and Cells
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• v.41 no.12
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• pp.1000-1007
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• 2018

Mitochondria and endoplasmic reticulum (ER) are essential organelles in eukaryotic cells, which play key roles in various biological pathways. Mitochondria are responsible for ATP production, maintenance of $Ca^{2+}$ homeostasis and regulation of apoptosis, while ER is involved in protein folding, lipid metabolism as well as $Ca^{2+}$ homeostasis. These organelles have their own functions, but they also communicate via mitochondrial-associated ER membrane (MAM) to provide another level of regulations in energy production, lipid process, $Ca^{2+}$ buffering, and apoptosis. Hence, defects in MAM alter cell survival and death. Here, we review components forming the molecular junctions of MAM and how MAM regulates cellular functions. Furthermore, we discuss the effects of impaired ER-mitochondrial communication in various neurodegenerative diseases.

• BMB Reports
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• v.41 no.5
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• pp.345-352
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• 2008

The cerebral microvessels possess barrier characteristics which are tightly sealed excluding many toxic substances and protecting neural tissues. The specialized blood-neural barriers as well as the cerebral microvascular barrier are recognized in the retina, inner ear, spinal cord, and cerebrospinal fluid. Microvascular endothelial cells in the brain closely interact with other components such as astrocytes, pericytes, perivascular microglia and neurons to form functional 'neurovascular unit'. Communication between endothelial cells and other surrounding cells enhances the barrier functions, consequently resulting in maintenance and elaboration of proper brain homeostasis. Furthermore, the disruption of the neurovascular unit is closely involved in cerebrovascular disorders. In this review, we focus on the location and function of these various blood-neural barriers, and the importance of the cell-to-cell communication for development and maintenance of the barrier integrity at the neurovascular unit. We also demonstrate the close relation between the alteration of the blood-neural barriers and cerebrovascular disorders.

• BMB Reports
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• v.40 no.5
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• pp.690-696
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• 2007

There are conflicting views for the polymerization process of human UDP-glucose dehydrogenase (UGDH) and no clear evidence has been reported yet. Based on crystal coordinates for Streptococcus pyogenes UGDH, we made double mutant A222Q/S233G. The double mutagenesis had no effects on expression, stability, and secondary structure. Interestingly, A222Q/S233G was a dimeric form and showed an UGDH activity, although it showed increased $K_m$ values for substrates. These results suggest that Ala222 and Ser233 play an important role in maintaining the hexameric structure and the reduced binding affinities for substrates are attributable to its altered subunit communication although quaternary structure may not be critical for catalysis.

• Molecules and Cells
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• v.21 no.3
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• pp.315-329
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• 2006

Two, well characterized cationic channels, the ryanodine receptor (RyR) and the canonical transient receptor potential cation channel (TRPC) are briefly reviewed with a particular attention on recent developments related to the interplay between the two channel families.

• Journal of Ginseng Research
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• v.47 no.5
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• pp.615-621
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• 2023

Korean Red Ginseng (KRG) plays a key role in heme oxygenase (HO)-1 induction under physical and moderate oxidative stress conditions. The transient and mild induction of HO-1 is beneficial for cell protection, mitochondrial function, regeneration, and intercellular communication. However, chronic HO-1 overexpression is detrimental in severely injured regions. Thus, in a chronic pathological state, diminishing HO-1-mediated ferroptosis is beneficial for a therapeutic approach. The molecular mechanisms by which KRG protects various cell types in the central nervous system have not yet been established, especially in terms of HO-1-mediated mitochondrial functions. Therefore, in this review, we discuss the multiple roles of KRG in the regulation of astrocytic HO-1 under pathophysiological conditions. More specifically, we discuss the role of the KRG-mediated astrocytic HO-1 pathway in regulating mitochondrial functions in acute and chronic neurodegenerative diseases as well as physiological conditions.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1505-1509
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• 2008

Comparative molecular simulations were performed to establish molecular interaction and inhibitory effect of flavonoid myricetin on formation of amyloid fibris. For computational comparison, the conformational stability of myricetin with amyloid $\beta$ -peptide (A$\beta$ ) and $\beta$ -amyloid fibrils (fA$\beta$) were traced with multiple molecular dynamics simulations (MD) using the CHARMM program from Monte Carlo docked structures. Simulations showed that the inhibition by myricetin involves binding of the flavonoid to fA$\beta$ rather than A$\beta$ . Even in MD simulations over 5 ns at 300 K, myricetin/fA$\beta$ complex remained stable in compact conformation for multiple trajectories. In contrast, myricetin/A$\beta$ complex mostly turned into the dissociated conformation during the MD simulations at 300 K. These multiple MD simulations provide a theoretical basis for the higher inhibitory effect of myricetin on fibrillogenesis of fA$\beta$ relative to A$\beta$ . Significant binding between myricetin and fA$\beta$ observed from the computational simulations clearly reflects the previous experimental results in which only fA$\beta$ had bound to the myricetin molecules.