• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1261-1271
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• 2020

Cytochrome c_L (Cytc_L) is an essential protein in the process of methanol oxidation in methylotrophs. It receives an electron from the pyrroloquinoline quinone (PQQ) cofactor of methanol dehydrogenase (MDH) to produce formaldehyde. The direct electron transfer mechanism between Cytc_L and MDH remains unknown due to the lack of structural information. To help gain a better understanding of the mechanism, we determined the first crystal structure of heme c containing Cytc_L from the aquatic methylotrophic bacterium Methylophaga aminisulfidivorans MP^T at 2.13 Å resolution. The crystal structure of Ma-Cytc_L revealed its unique features compared to those of the terrestrial homologues. Apart from Fe in heme, three additional metal ion binding sites for Na⁺, Ca⁺, and Fe²⁺ were found, wherein the ions mostly formed coordination bonds with the amino acid residues on the loop (G93-Y111) that interacts with heme. Therefore, these ions seemed to enhance the stability of heme insertion by increasing the loop's steadiness. The basic N-terminal end, together with helix α4 and loop (G126 to Y136), contributed positive charge to the region. In contrast, the acidic C-terminal end provided a negatively charged surface, yielding several electrostatic contact points with partner proteins for electron transfer. These exceptional features of Ma-Cytc_L, along with the structural information of MDH, led us to hypothesize the need for an adapter protein bridging MDH to Cytc_L within appropriate proximity for electron transfer. With this knowledge in mind, the methanol oxidation complex reconstitution in vitro could be utilized to produce metabolic intermediates at the industry level.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1560-1568
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• 2013

Salmonella, a main cause of foodborne diseases, encounters a variety of environmental stresses and overcomes the stresses by multiple resistance strategies. One of the general responses to hyperosmotic stress is to import or produce compatible solutes so that cells maintain fluid balance and protect proteins and lipids from denaturation. The ProP and ProU systems are the main transport systems for compatible solutes. The OsmU system, recently identified as a third osmoprotectant transport system, debilitates excessive growth as well by reducing production of trehalose. We studied a fourth putative osmoprotectant transport system, YehZYXW, with high sequence similarity with the OsmU system. A Salmonella strain lacking YehZ, a predicted substrate-binding protein, did not suffer from hyperosmolarity but rather grew more rapidly than the wild type regardless of glycine betaine, an osmoprotectant, suggesting that the YehZYXW system controls bacterial growth irrespective of transporting glycine betaine. However, the growth advantage of ${\Delta}yehZ$ was not attributable to an increase in OtsBA-mediated trehalose production, which is responsible for the outcompetition of the ${\Delta}osmU$ strain. Overexpressed YehZ in trans was capable of deaccelerating bacterial growth vice versa, supporting a role of YehZ in dampening growth. The expression of yehZ was increased in response to nutrient starvation, acidic pH, and the presence of glycine betaine under hyperosmotic stress. Identifying substrates for YehZ will help decipher the role of the YehZYXW system in regulating bacterial growth in response to environmental cues.

• Journal of Oriental Neuropsychiatry
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• v.17 no.2
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• pp.75-89
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• 2006

Objective : This experiment was designed to investigate the effect of Rhododendron simsii Planch(RSP) on the Alzheimer's disease. Method : The effects of RSP on amyloid precursor proteins(APP), acetylcholinesterase (AChE), glial fibrillary acidic protein(GFAP) mRNA of PC-12 cell treated by amyloid ${\beta}$ protein$(A{\beta})$ and $IL-1{\beta}$, IL-6, $TNF-{\alpha}$ mRNA of THP-1 cell treated by lipopolysaccharide(LPS), AChE activity of PC-12 cell lysate treated by $A{\beta}$ and behavior of the memory deficit mice induced by scopolamine, and glucose, AChE in serum of the memory deficit mice induced by scopolamine were investigated, respectively. Result : 1. RSP suppressed APP, AChE, GFAP mRNA in PC-12 celt treated by $A{\beta}$. 2. RSP suppressed $IL-1{\beta}$, IL-6, $TNF-{\alpha}$ mRNA in THP-1 cell treated by LPS. 3. RSP suppressed AChE activity in cell lysate of PC-12 cell treated by $A{\beta}$. 4. RSP increased glucose and decreased AChE significantly in the serum of the memory deficit mice induced by scopolamine. 5. RSP group showed significantly inhibitory effect on the scopolamine-induced impairment of teaming and. memory in the experiment of Morris water maze. Conclusion : According to the above results, it is suggested that RSP might be usefully applied for prevention and treatment of Alzheimer's disease and memory deficit symptom.

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.87-99
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• 2004

This experiment was designed to investigate the effect of Coptis japonica Makino(CJM) on the Alzheimer's disease. The effects of CJM extract on $IL-1{\beta}$, IL-6, amyloid precursor proteins (APP), acetylcholinesterase(AChE), glial fibrillary acidic protein(GFAP) mRNA of PC-12 cell treated by $A{\beta}$ plus $rIL-1{\beta}$ and AChE activity of PC-12 cell lysate treated by $A{\beta}$ plus $rIL-1{\beta}$ and behavior of memory deficit rats induced by scopolamine and mice glucose, uric acid, AChE activity of memory deficit rats induced by scopolamine were investigated, respectively. The results were summarized as follows ; 1. CJM extract suppressed $IL-1{\beta}$, IL-6 mRNA in PC-12 cell treated by $A{\beta}$ plus $rIL-1{\beta}$ 2. CJM extract suppressed APP, AChE, GFAP mRNA in PC-12 cell treated by $A{\beta}$ plus $rIL-1{\beta}$ 3. CJM extract suppressed AChE activity in cell lysate of PC-12 cell treated by $A{\beta}$ plus $rIL-1{\beta}$ 4. CJM extract group showed significantly inhibitory effect on the memory deficit of mice induced by scopolamine in the experiment of Morris water maze. 5. CJM extract increased glucose, decreased uric acid and AChE significantly in the serum of the memory deficit rats induced by scopolamine. According to the above results, it is suggested that CJM extract might be usefully applied for prevention and treatment of Alzheimer's disease and memory deficit symptom.

• Molecules and Cells
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• v.21 no.3
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• pp.428-435
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• 2006

Specific interaction of the epsin N-terminal homology(ENTH) domain with the plasma membrane appears to bridge other related proteins to the specific regions of the membrane that are invaginated to form endocytic vesicles. An additional $\alpha$-helix, referred to as helix 0 (H0), is formed in the presence of the soluble ligand inositol-1,4,5-trisphosphate [$Ins(1,4,5)P_3$] at the N terminus of the ENTH domain (amino acid residues 3-15). The ENTH domain alone and full-length epsin cause tubulation of liposomes made of brain lipids. Thus, it is believed that H0 is membrane-inserted when it is coordinated with the phospholipid phosphatidylinositol-4,5-bisphosphate [$PtdIns(4,5)P_2$], resulting in membrane deformation as well as recruitment of accessory factors to the membrane. However, formation of H0 in a real biological membrane has not been demonstrated. In the present study, the membrane structure of H0 was determined by measurement of electron paramagnetic resonance (EPR) nitroxide accessibility. H0 was located at the phosphate head-group region of the membrane. Moreover, EPR line-shape analysis indicated that no pre-formed H0-like structure were present on normal acidic membranes. $PtdIns(4,5)P_2$ was necessary and sufficient for interaction of the H0 region with the membrane. H0 was stable only in the membrane. In conclusion, the H0 region of the ENTH domain has an intrinsic ability to form H0 in a $PtdIns(4,5)P_2$-containing membrane, perhaps functioning as a sensor of membrane patches enriched with $PtdIns(4,5)P_2$ that will initiate curvature to form endocytic vesicles.

• Journal of Life Science
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• v.14 no.2
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• pp.309-314
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• 2004

Cyclic AMP receptor protein (CRP) is involved in the transcriptional regulation of more than 100 genes in E. coli. CRP dimer is converted into active form via the sequential conformation change of cAMP binding pocket, hinge region and HTH DNA binding motif by binding of cAMP. The temperature gradient gel electrophoresis (TGGE) was applied to CRP protein to know whether it was an efficient technique to study the conformational transitions and the thermal stability. TGGE showed the unfolding process of wild-type and S83G CRP proteins with the temperature gradient set from 29 to 71$^{\circ}C$ on nondenaturing polyacrylamide gel. Melting temperature (Tm) was 57$\pm$1 and 55$\pm$1$^{\circ}C$ for wild-type and S83G CRP, respectively in acidic buffer[89.8 mM Glycine and 24 mM Boric acid (pH 5.8)].

• Genomics & Informatics
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• v.11 no.4
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• pp.245-253
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• 2013

A radioresistant cell line was established by fractionated ionizing radiation (IR) and assessed by a clonogenic assay, flow cytometry, and Western blot analysis, as well as zymography and a wound healing assay. Microarray was performed to profile global expression and to search for differentially expressed genes (DEGs) in response to IR. H460R cells demonstrated increased cell scattering and acidic vesicular organelles compared with parental cells. Concomitantly, H460R cells showed characteristics of increased migration and matrix metalloproteinase activity. In addition, H460R cells were resistant to IR, exhibiting reduced expression levels of ionizing responsive proteins (p-p53 and ${\gamma}$-H2AX); apoptosis-related molecules, such as cleaved poly(ADP ribose) polymerase; and endoplasmic reticulum stress-related molecules, such as glucose-regulated protein (GRP78) and C/EBP-homologous protein compared with parental cells, whereas the expression of anti-apoptotic X-linked inhibitor of apoptosis protein was increased. Among DEGs, syntrophin beta 2 (SNTB2) significantly increased in H460R cells in response to IR. Knockdown of SNTB2 by siRNA was more sensitive than the control after IR exposure in H460, H460R, and H1299 cells. Our study suggests that H460R cells have differential properties, including cell morphology, potential for metastasis, and resistance to IR, compared with parental cells. In addition, SNTB2 may play an important role in radioresistance. H460R cells could be helpful in in vitro systems for elucidating the molecular mechanisms of and discovering drugs to overcome radioresistance in lung cancer therapy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.85-94
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• 2002

Antibodies raised against the purified p-subunit of $\beta$-conglycinin were used in immunohistochemical studies to monitor the pattern of $\beta$-conglycinin mobilization in the cotyledons during soybean [Glycine max (L.) Merr.] seed germination. Western blot analysis revealed that the break down of the $\beta$-subunit of $\beta$-conglycinin commenced as early as 2 days after seed imbibition (DAI). Concurrent with the degradation of the $\beta$-subunit of $\beta$-conglycinin, accumulation of 48, 28, and 26 kD proteolytic intermediates was observed from 2 to 6 DAI. Western blot analysis also revealed that the acidic subunit of glycinin was mobilized earlier than the basic subunit. The basic glycinin subunit was subjected to proteolysis within 2 DAI resulting in the appearance of an intermediate product approximately 2 kD smaller than the native basic glycinin subunit. In contrast to the major seed storage proteins, lipoxygenase was subjected to limited proteolysis and was detected even after 8 DAI. The first sign of $\beta$-conglycinin breakdown was observed near the vascular strands and proceeded from the vascular strands towards the epidermis. Protein A-gold localization studies using thin sections of soybean cotyledons and antibodies raised against the $\beta$-subunit of $\beta$-conglycinin revealed intense labeling over protein bodies. A pronounced decrease in the protein A-gold labeling intensity over protein bodies was observed at later stages of seed germination. The protein bodies, which were converted into a large central vacuole by 8 DAI, contained very little 7S protein as evidenced by sparse protein A-gold labeling in the vacuoles.

• Journal of Oriental Neuropsychiatry
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• v.16 no.1
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• pp.81-96
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• 2005

This experiment was designed to investigate the effect of Dichroa febrifuga(DIF) on the Alzheimer’s disease. The effects of DIF extract on $IL-1{\beta}$, IL-6, $TNF-{\alpha}$ mRNA of THP-1 cell treated by $A{\beta}$ plus LPS and amyloid precursor proteins(APP), acetylcholinesterase(AChE), glial fibrillary acidic protein(GFAP) mRNA of PC-12 cell treated by $A{\beta}$ plus $rIL-1{\beta}$ and AChE activity of PC-12 cell lysate treated by $A{\beta}$ plus $rIL-1{\beta}$ and behavior of memory deficit mice induced by scopolamine and mice glucose, uric acid, AChE activity of memory deficit rats induced by scopolamine were investigated, respectively. The results were summarized as follows ; 1. DIF extract suppressed APP, AChE, GFAP mRNA in PC-12 cell treated by $A{\beta}$. 2. DIF extract suppressed $IL-1{\beta}$, IL-6, $TNF-{\alpha}$ mRNA in THP-1 cell treated by LPS. 3. DIF extract suppressed AChE activity in cell lysate of PC-12 cell treated by $A{\beta}$. 4. DIF extract increased glucose, decreased uric acid and AChE significantly in the serum of the memory deficit rats induced by scopolamine. 5. DIF extract group showed significantly inhibitory effect on the memory deficit of mice induced by scopolamine in the experiment of Morris water maze. According to the above results, it is suggested that DIF extract might be usefully applied for prevention and treatment of Alzheimer’s disease and memory deficit.

• Journal of Oriental Neuropsychiatry
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• v.16 no.1
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• pp.67-80
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• 2005

This experiment was designed to investigate the effect of Rheum palmatum(RHP) on the Alzheimer's disease. The effects of RHP extract on amyloid precursor proteins(APP), acetylcholinesterase(AChE), glial fibrillary acidic protein(GFAP) mRNA of PC-12 cell treated by $A{\beta}\;and\;IL-1{\beta},\;IL-6,\;TNF-{\alpha}$ mRNA of THP-1 cell treated by LPS and AChE activity of PC-12 cell lysate treated by $A {\beta}$and behavior of memory deficit rats induced by scopolamine and mice glucose, uric acid, AChE activity of memory deficit rats induced by scopolamine were investigated, respectively. The results were summarized as follows ; 1. RHP extract suppressed APP, AChE, GFAP mRNA in PC-12 cell treated by $A{\beta} $. 2. RHP extract suppressed $IL-1{\beta} $, IL-6 $TNF-{\alpha}$ mRNA in THP-1 cell treated by LPS. 3. RHP extract suppressed AChE activity in cell lysate of PC-12 cell treated by $A{\beta}$. 4. HP extract increased glucose, decreased uric acid and AChE significantly in the serum of the memory deficit rats induced by scopolamine. 5. RHP extract group showed significantly inhibitory effect on the memory deficit of mice induced by scopolamine in the experiment of Morris water maze. According to the above results, it is suggested that RHP extract might be usefully applied for prevention and treatment of Alzheimer’s disease and memory deficit symptom.