• Journal of Life Science
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• v.23 no.7
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• pp.941-946
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• 2013

Local protein synthesis at subsynaptic sites plays a key role in the regulation of the protein composition in local domains. In this study, we carried out immunocytochemistry of cultured rat hippocampal neurons in various developmental stages to investigate the expression of eIF4E and its binding protein, eIF4EBP1. Both proteins were distributed in dendrites. In addition, eIF4EBP1 was highly expressed in the nucleus throughout the development, whereas eIF4E was not expressed in the nucleus. Punctate expression of eIF4E and eIF4EBP1 was evident in DIV 3. The colocalization rates of eIF4E or eIF4EBP1 puncta with PSD95 were higher in the dendrogenic than in the mature stages. In contrast, the colocalization rates of eIF4E and eIF4EBP1 puncta were higher in the mature than in the dendrogenic stages. As eIF4E is inactive when it is bound to eIF4EBP1, these data indicate that most dendritic eIF4E's are active during development but that they are mostly under inhibition in mature neurons.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.550-553
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• 2003

The genes of GFPuv and Cytochrome c-552 were amplified by using PCR, and then, fused each other. Fusion gene of GFPuv and Cytochrome c-552 was inserted into the pTrcHis B vector and transferred to E. coli. A fusion protein of GFPuv and Cytochrome c-552 was expressed in JM109 and BL21. This fusion protein was composed of a His-tag for the rapid one-step purification using an immobilized metal affinity chromatography.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.451-455
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• 1996

Physiological studies on the expression of Bacillus thuringiensis subsp. tenebrionis (Btt) gene coding for insecticidal protein in recombinant Escherichia coli 537 were carried out to identify optimal culture condition. It was necessary to shift culture temperature from 30 to $42^{\circ}C$ to express the gene. Expression of the Btt toxin gene by recombinant E. coli 537 began within one hour after induction. Complex nitrogen sources increased production of the insecticidal protein. The total insecticidal protein was 0.5 g/I when using yeast extract as a complex nitrogen source. Soybean hydrolysate showed apparently the highest induction efficiency. After induction, the cellular content of the insecticidal protein was 5.4 times higher than it had been before induction. The optimal cultivation strategy was found to grow cells for 7hours at $30^{\circ}C$ and then 5-8 hours at $42^{\circ}C$. The optimal cultivation pH for the production of insecticidal protein was 6.5. The Btt toxin produced by the recombinant E. coli 537 was found to have the same level of potency against Colorado potato beetle as the original toxin.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.206-212
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• 1999

The gene orf7(oxi III) was expressed using an E. coli system in anticipation that it would encode dTDP-glucose 4,6-dehydratase which is involved in the biosynthesis of the olivose moiety of chlorothricin produced from Streptomyces antibioticus Tu99. The solubility of the expressed protein increased up to 20% under optimal induction conditions. The expressed protein was purified from the E. coli BL 21(DE3) cell lysate by a 28.5-fold purification in two chromatography steps with a 38% recovery to near homogeneity. The molecular weight and N-terminal amino acid sequence of the purified protein correlated with the predicted mass and sequence deduced from the orf7 gene. The purified protein was a homodimer with a subunit relative molecular weight of 38,000 Dalton. The expressed protein was found to exhibit dTDP-glucose 4,6-dehydratase activity and be highly specific for dTDP-glucose as a substrate. The values of K'm and V'max for dTDP-glucose were 28 $\mu$M and 295 nmol $min^{-1} (mg protein)^{-1}$, respectively. dTTP and dTDP were strong inhibitors of this enzyme.$NAD^+$, the coenzyme for dTDP-glucose 4,6-dehydratase, was tightly bound to the expressed protein.

• BMB Reports
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• v.39 no.6
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• pp.717-721
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• 2006

In vitro analyses of type I signal peptidase activities require protein precursors as substrates. Usually, these pre-proteins are expressed in vitro and cleavage of the signal sequence is followed by SDS polyacrylamide gel electrophoresis coupled with autoradiography. Radioactive amino acids have to be incorporated in the expressed protein, since the amount of the in vitro expressed protein is usually very low and processing of the signal peptide cannot be followed by SDS polyacrylamide gel electrophoresis alone. Here we describe a rapid and simple method to express large amounts of a protein precursor in E. coli. We have analyzed the effect of ionophors as well as of azide on the accumulation of expressed protein precursors. Azide blocks the function of SecA and the ionophors dissipate the electrochemical gradient across the cytoplasmic membrane of E. coli. Addition of azide ions resulted in the formation of inclusion bodies, highly enriched with pre-apo-plastocyanine. Plastocyanine is a soluble copper protein, which can be found in the periplasmic space of cyanobacteria as well as in the thylakoid lumen of cyanobacteria and chloroplasts, and the pre-protein contains a cleavable signal sequence at its N-terminus. After purification of cyanobacterial pre-apo-plastocyanine, its signal sequence can be cleaved off by the E. coli signal peptidase, and protein processing was followed on Coomassie stained SDS polyacrylamide gels. We are optimistic that the presented method can be further developed and applied.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.807-811
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• 2007

Diabetes is marked by high glucose levels and is associated with decreased bone mass and increased fracture rates. To determine if [6]-gingerol could influence osteoblast dysfunction induced by 2-deoxy-D-ribose (dRib), osteoblastic MC3T3-E1 cells was treated with dRib and [6]-gingerol and markers of osteoblast function and oxidized protein were examined. [6]-Gingerol ($10^{-7}\;M$) significantly increased the growth of MC3T3-E1 cells in the presence of 30 mM dRib (p<0.05). [6]-Gingerol ($10^{-7}\;M$) caused a significant elevation of alkaline phosphatase (ALP) activity, collagen content, and osteocalcin secretion in the cells. We then examined the effect of [6]-gingerol on the production of osteoprotegerin and protein carbonyl in osteoblasts. Treatment with [6]-gingerol ($10^{-9}$ and $10^{-7}\;M$) increased osteoprotegerin secretion in osteoblastic cells. Moreover, [6]-gingerol ($10^{-9}$ and $10^{-7}\;M$) decreased protein carbonyl contents of osteoblastic MC3T3-E1 cells in the presence of 30 mM dRib. Taken together, these results demonstrate that [6]-gingerol inhibits dRib-induced damage and may be useful in the treatment of diabetes related bone diseases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1795-1799
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• 2008

The heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a component of hnRNP complexes. This protein binds strongly to cytidine-rich RNA/DNA sequences. It is a nucleocytoplasmic shuttling protein. To investigate the functions of hnRNP K, I searched for hnRNP K-interacting proteins in HeLa cDNA library using a yeast two-hybrid screening system. One of the cDNA clones is identical to human hnRNP E1 (poly(rC) binding protein 1) cDNA (GenBank accession number XM_031585). In this study, hnRNP K is shown to specifically interact with hnRNP E1 in yeast two-hybrid system and in vitro biochemical assay.

• Biomolecules & Therapeutics
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• v.29 no.5
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• pp.527-535
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• 2021

Sclerostin (SOST), a regulator of bone formation in osteocytes, inhibits the canonical Wnt signaling by interacting with low-density lipoprotein receptor-related protein 5/6 (LRP5/6) to prevent Wnt binding. Loss-of-function mutations of the SOST gene caused massive bone outgrowth and SOST-null mouse exhibited a high bone density phenotype. Therefore, SOST has been suggested as a promising therapeutic target for osteoporosis. A few previous studies with X-ray crystallography identified the binding interfaces between LRP6 and SOST, but there are limitations in these studies as they used truncated SOST protein or SOST peptide. Here, we analyzed the conformational dynamics of SOST-LRP6 E1E2 complex using hydrogen/deuterium exchange mass spectrometry (HDX-MS). We examined the effect of the C-terminal tail of SOST on LRP6 conformation upon complex formation. HDX-MS analysis suggested a new potential binding interface for the C-terminal region of SOST that was missing from the previous crystal structure of the SOST-LRP6 E1E2 complex.

• Genomics & Informatics
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• v.12 no.2
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• pp.64-70
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• 2014

Human papillomavirus (HPV) infection is the leading cause of cancer mortality among women worldwide. The life-threatening infection caused by HPV demands the need for designing anticancerous drugs. In the recent years, different compounds from natural origins, such as carrageenan, curcumin, epigallocatechin gallate, indole-3-carbinol, jaceosidin, and withaferin, have been used as a hopeful source of anticancer therapy. These compounds have been shown to suppress HPV infection by different researchers. In the present study, we explored these natural inhibitors against E6 oncoprotein of high-risk HPV-16, which is known to inactivate the p53 tumor suppressor protein. A robust homology model of HPV-16 E6 was built to anticipate the interaction mechanism of E6 oncoprotein with natural inhibitory molecules using a structure-based drug designing approach. Docking analysis showed the interaction of these natural compounds with the p53-binding site of E6 protein residues 113-122 (CQKPLCPEEK) and helped the restoration of p53 functioning. Docking analysis, besides helping in silico validation of natural compounds, also helps understand molecular mechanisms of protein-ligand interactions.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.10.1-10.6
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• 2014

Objectives Cigarette smoking had been recorded as the main cause of impaired endothelium-dependent vasodilation in smokers by reducing nitric oxide (NO), a production of endothelial nitric oxide synthase (eNOS). However, the mechanism of NO impairment via eNOS activity is unclear until now. In this study, cell passage is suggested to be a relevant factor to eNOS expression under cigarette smoking stress. Methods Bovine aortic endothelial cells (BAECs) were chosen as the research subject with passages ranking from 6 to 9 (6P to 9P). After exposure of cigarette smoking extract (CSE) solution, MTT assay and Western blot method were performed to check the cell viability as well as eNOS protein concentration. In these experiments, four concentrations of CSE at 0.5, 1, 2, and 4% were selected for treatment. Results Our results showed that cells almost died at 4% of CSE. Besides, eNOS protein mass had a linear decrease under the increase of CSE concentration. In addition, the effect of CSE on eNOS expression was dissimilar between different passages. Conclusions This study indicated that CSE had effect on both cell viability and eNOS expression. Besides, a reduction in protein mass was matched with the decrease of cell viability due to CSE tress. Last but not least, the response of eNOS protein to different concentration of CSE at different passages was disparate, making the hypothesis about cell passage related inhibition of eNOS caused by CSE solution.