• BMB Reports
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• v.43 no.4
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• pp.225-232
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• 2010

Parkinson's Disease (PD) is a common neurodegenerative disease characterized by the progressive degeneration of nigrostriatal dopaminergic (DA) neurons. Although the causative factors of PD remain elusive, many studies on PD animal models or humans suggest that glial activation along with neuroinflammatory processes contribute to the initiation or progression of PD. Additionally, several groups have proposed that dysfunction of the blood-brain barrier (BBB) combined with infiltration of peripheral immune cells play important roles in the degeneration of DA neurons. However, these neuroinflammatory events have only been investigated separately, and the issue of whether these phenomena are neuroprotective or neurotoxic remains controversial. We here review the current knowledge regarding the functions of these neuroinflammatory processes in the brain. Finally, we describe therapeutic strategies for the regulation of neuroinflammation with the goal of improving the symptoms of PD.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3542-3546
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• 2014

Relationship between molecular freedom of amyloidogenic protein and its self-assembly into amyloid fibrils has been evaluated with ${\alpha}$-synuclein, an intrinsically unfolded protein related to Parkinson's disease, by restricting its structural plasticity through an end-to-end disulfide bond formation between two newly introduced cysteine residues on the N- and C-termini. Although the resulting circular form of ${\alpha}$-synuclein exhibited an impaired fibrillation propensity, the restriction did not completely block the protein's interactive core since co-incubation with wild-type ${\alpha}$-synuclein dramatically facilitated the fibrillation by producing distinctive forms of amyloid fibrils. The suppressed fibrillation propensity was instantly restored as the structural restriction was unleashed with ${\beta}$-mercaptoethanol. Conformational flexibility of the accreting amyloidogenic protein to pre-existing seeds has been demonstrated to be critical for fibrillar extension process by exerting structural adjustment to a complementary structure for the assembly.

• Journal of Microbiology
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• v.39 no.3
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• pp.149-153
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• 2001

The electron transfer reaction is one of the most essential processes of life. Not only does it provide the means of transforming solar and chemical energy into a utilizable form for all living organisms, it also extends into a range of metabolic processes that support the life of a cell. Thus, it is of great interest to understand the physical basis of the rates and reduction potentials of these reactions. To identify the major determinants of reduction potentials in redox proteins, we have chosen the simplest electron transfer protein, rubredoxin, a small (52-54 residue) iron-sulfur protein family, widely distributed in bacteria and archaea. Rubredoxins can be grouped into two classes based on the correlation of their reduction potentials with the identity of residue 44; those with Ala44 (ex: Pyrococcus furiosus) have reduction potentials that are ∼50 mV higher than those with Va144 (ex: Clostridium pasteurianum). Based on the crystal structures of rubredoxins from C. pasteurianum and P. furiosus, we propose the identity of residue 44 alone determines the reduction potential by the orientation of the electric dipole moment of the peptide bond between 43 and 44. Based on 1.5 $\AA$ resolution crystal structures and molecular dynamics simulations of oxidized and reduced rubredoxins from C. pasteurianum, the structural rearrangements upon reduction suggest specific mechanisms by which electron transfer reactions of rubredoxin should be facilitated.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.111-114
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• 2004

Molecular imaging provides a visualization of normal as well as abnormal cellular processes at a molecular or genetic level rather than at a anatomical level. Conventional medical imaging methods utilize the imaging signals produced by nonspecific physico-chemical interaction. However, molecular imaging methods utilize the imaging signals derived from specific cellular or molecular events. Because molecular and genetic changes precede anatomical change in the course of disease development, molecular imaging can detect early events in disease progression. in the near future, through molecular imaging we can understand basic mechanisms of disease, and diagnose earlier and, subsequently, treat earlier intractable diseases such as cancer, neuro-degenerative diseases, and immunologic disorders. In beginning period, nuclear medicine started as a molecular imaging, and has had a leading role in the field of molecular imaging. But recently molecular imaging has been rapidly developed. Besides nuclear imaging, molecular imaging methods such as optical imaging, magnetic resonance imaging are emerging. Each imaging modalities have their advantages and weaknesses. The opportunities from molecular imaging look bright. We should try nuclear medicine continues to have a leading role in molecular imaging.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.932-938
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• 2007

The interaction between adherent molecules and gas molecules was modeled in molecular scale and simulated by the molecular dynamics method in order to understand the evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantify and gas molecular collisions because the industrial oil has too complex structures of fatty acid. The effects of adherent quantify, gas temperature and surface temperature for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on surface temperature shown in the experimental results.

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.121-128
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• 2006

The interaction between adherent molecules and gas molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantity and gas molecular collisions because the industrial oil has too complex structures of fatty acid. Effects of adherent quantity, gas temperature, surface temperature and adhesion strength for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on the surface temperature shown in the experimental results.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.27-27
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• 2011

For the design of real applicable molecular devices, current-voltage properties through molecular nanostructures such as metal-molecule-metal junctions (molecular junctions) have been studied extensively. In thiolate monolayers on the gold electrode, the chemical bonding of sulfur to gold and the van der Waals interactions between the alkyl chains of neighboring molecules are important factors in the formation of well-defined monolayers and in the control of the electron transport rate. Charge transport through the molecular junctions depends significantly on the energy levels of molecules relative to the Fermi levels of the contacts and the electronic structure of the molecule. It is important to understand the interfacial electron transport in accordance with the increased film thickness of alkyl chains that are known as an insulating layer, but are required for molecular device fabrication. Thiol-tethered RuII terpyridine complexes were synthesized for a voltage-driven molecular switch and used to understand the switch-on mechanism of the molecular switches of single metal complexes in the solid-state molecular junction in a vacuum. Electrochemical voltammetry and current-voltage (I-V) characteristics are measured to elucidate electron transport processes in the bistable conducting states of single molecular junctions of a molecular switch, Ru(II) terpyridine complexes. (1) On the basis of the Ru-centered electrochemical reaction data, the electron transport rate increases in the mixed self-assembled monolayer (SAM) of Ru(II) terpyridine complexes, indicating strong electronic coupling between the redox center and the substrate, along the molecules. (2) In a low-conducting state before switch-on, I-V characteristics are fitted to a direct tunneling model, and the estimated tunneling decay constant across the Ru(II) terpyridine complex is found to be smaller than that of alkanethiol. (3) The threshold voltages for the switch-on from low- to high-conducting states are identical, corresponding to the electron affinity of the molecules. (4) A high-conducting state after switch-on remains in the reverse voltage sweep, and a linear relationship of the current to the voltage is obtained. These results reveal electron transport paths via the redox centers of the Ru(II) terpyridine complexes, a molecular switch.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.115-120
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• 2004

Molecular imaging is a rapidly growing field due to the advances in molecular biology and imaging technologies. With the introduction of imaging reporter genes into the cell, diverse cellular processes can be monitored, quantified and imaged non-invasively in vivo. These precesses include the gene expression, protein-protein interactions, signal transduction pathways, and monitoring of cells such as cancer cells, immune cells, and stem cells. In the near future, molecular imaging analysis will allow us to observe the incipience and progression of the disease. These will make us easier to give a diagnosis in the early stage of intractable diseases such as canter, neuro-degenerative disease, and immunological disorders. Additionally, molecular imaging method will be a valuable tool for the real-time evaluation of cells in molecular biology and the basic biological studies. As newer and more powerful molecular imaging tools become available, it will be necessary to corporate clinicians, molecular biologists and biochemists for the planning, interpretation, and application of these techniques to their fullest potential. in order for such a multidisciplinary team to be effective, it is essential that a common understanding of basic biochemical and molecular biologic techniques is achieved. Basic molecular techniques for molecular imaging methods are presented in this paper.

• Journal of Life Science
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• v.8 no.2
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• pp.223-233
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• 1998

Discovery of molecular chaperone has stimulate cell biologists and thus made it possible to re-examine the processes whereby proteins achieve and maintain their functional conformations within living cells. the term ‘Molecular chaperone’ was first coined to describe one particular protein involved in the assembly of nucleosomes, but the term has now been extended to describe the function of a wide variety of proteins that assist protein transport across membranes, folding of nascent polypeptide, the assembly and disassembly of oligomeric structures, and the recovery or removal of proteins damaged by various environmental stresses including heat shock. Progress of molecular chaperone research is still limited by the lack of 3-dimensional structural information and detailed interacts with taget proteins in the cell. However, several laboratories around the world are attempting to extend our knowledge on the functions of molecular chaperone, and such efforts seem justified to finally provide the answers to the most burning questions shortly.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.47-51
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• 2011

We investigated the substrate surface polishing by the spherical rigid abrasive under the compression using classical molecular dynamics modeling. We performed three-dimensional molecular dynamic simulations using the Morse potential functions for the various slide-to-roll ratios, from 0 to 1, and then, the compressive forces acting on the spherical rigid abrasive were calculated as functions of the time and the slide-to-roll ratio. The friction coefficients obtained from the classical molecular dynamics simulations were compared to those obtained from the experiments; and found that the molecular dynamic simulation results with the slide-to-roll ratio of 0 value were in good agreement with the experimental results.