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61.
Previously, we isolated and characterized attacin from Spodoptera exigua and a coleoptericin-like protein from Protaetia brevitarsis seulensis. In this study, we fused these two genes encoding antimicrobial proteins to obtain a hybrid protein with enhanced antimicrobial activity. To fuse the two antimicrobial proteins, we employed helical and non-helical linker sequences that function as inter-domain linkers in proteins. We used the Gly–Gly–Gly–Gly–Ser peptide as a non-helical linker. The hybrid protein produced using this linker showed less antimicrobial activity against Escherichia coli, Bacillus subtilis, Burkholderia glumae, Pseudomonas corrugate, and Erwinia rhapontici than either of the two parental antimicrobial proteins. In addition, the MIC value of the hybrid protein was 23.1 μM, which indicates poor activity against E. coli. When we used three Glu–Ala–Ala–Ala–Lys (EAAAK) peptide sequences as a helical linker to fuse the two proteins, the resultant hybrid protein had much higher antimicrobial activity than the parental antimicrobial proteins. In particular, this hybrid protein had strong antimicrobial activity against P. corrugate. These results indicate that the EAAAK motif can be used to effectively separate two antimicrobial proteins and produce a hybrid protein with more antimicrobial activity than either of the parent proteins. 相似文献
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63.
Jung Hwan Yoon Mi La Cho Yoo Jin Choi Ji Yeon Back Mi Kyung Park Suk Woo Lee Byung Joon Choi Hassan Ashktorab Duane T. Smoot Suk Woo Nam Jung Young Lee Won Sang Park 《Journal of cellular biochemistry》2013,114(8):1800-1809
Gastrokine 1 (GKN1) plays an important role in the gastric mucosal defense mechanism and also acts as a functional gastric tumor suppressor. In this study, we examined the effect of GKN1 on the expression of inflammatory mediators, including NF‐κB, COX‐2, and cytokines in GKN1‐transfected AGS cells and shGKN1‐transfected HFE‐145 cells. Lymphocyte migration and cell viability were also analyzed after treatment with GKN1 and inflammatory cytokines in AGS cells by transwell chemotaxis and an MTT assay, respectively. In GKN1‐transfected AGS cells, we observed inactivation and reduced expression of NF‐κB and COX‐2, whereas shGKN1‐transfected HFE‐145 cells showed activation and increased expression of NF‐κB and COX‐2. GKN1 expression induced production of inflammatory cytokines including IL‐8 and ‐17A, but decreased expression of IL‐6 and ‐10. We also found IL‐17A expression in 9 (13.6%) out of 166 gastric cancer tissues and its expression was closely associated with GKN1 expression. GKN1 also acted as a chemoattractant for the migration of Jurkat T cells and peripheral B lymphocytes in the transwell assay. In addition, GKN1 significantly reduced cell viability in both AGS and HFE‐145 cells. These data suggest that the GKN1 gene may inhibit progression of gastric epithelial cells to cancer cells by regulating NF‐κB signaling pathway and cytokine expression. J. Cell. Biochem. 114: 1800–1809, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
64.
Hye Jung Lee Sailila E. Abdula Dae Won Jang Sung-Han Park Ung-Han Yoon Yu Jin Jung Kwon Kyoo Kang Ill Sup Nou Yong-Gu Cho 《Plant cell reports》2013,32(10):1521-1529
Key message
Overexpression of OsGS gene modulates oxidative stress response in rice after exposure to cadmium stress. Our results describe the features of transformants with enhanced tolerance to Cd and abiotic stresses.Abstract
Glutamine synthetase (GS) (EC 6.3.1.2) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Exposure of plants to cadmium (Cd) has been reported to decrease GS activity in maize, pea, bean, and rice. To better understand the function of the GS gene under Cd stress in rice, we constructed a recombinant pART vector carrying the GS gene under the control of the CaMV 35S promoter and OCS terminator and transformed using Agrobacterium tumefaciens. We then investigated GS overexpressing rice lines at the physiological and molecular levels under Cd toxicity and abiotic stress conditions. We observed a decrease in GS enzyme activity and mRNA expression among transgenic and wild-type plants subjected to Cd stress. The decrease, however, was significantly lower in the wild type than in the transgenic plants. This was further validated by the high GS mRNA expression and enzyme activity in most of the transgenic lines. Moreover, after 10 days of exposure to Cd stress, increase in the glutamine reductase activity and low or no malondialdehyde contents were observed. These results showed that overexpression of the GS gene in rice modulated the expression of enzymes responsible for membrane peroxidation that may result in plant death. 相似文献65.
66.
Sun Wook Cho Flavia Q. Pirih Amy J. Koh Megan Michalski Matthew R. Eber Kathryn Ritchie Benjamin Sinder Seojin Oh Saja A. Al-Dujaili JoonHo Lee Ken Kozloff Theodora Danciu Thomas J. Wronski Laurie K. McCauley 《The Journal of biological chemistry》2013,288(10):6814-6825
Both PTH and IL-6 signaling play pivotal roles in hematopoiesis and skeletal biology, but their interdependence is unclear. The purpose of this study was to evaluate the effect of IL-6 and soluble IL-6 receptor (sIL-6R) on hematopoietic and skeletal actions of PTH. In the bone microenvironment, PTH stimulated sIL-6R protein levels in primary osteoblast cultures in vitro and bone marrow in vivo in both IL-6+/+ and IL-6−/− mice. PTH-mediated hematopoietic cell expansion was attenuated in IL-6−/− compared with IL-6+/+ bone marrow, whereas sIL-6R treatment amplified PTH actions in IL-6−/− earlier than IL-6+/+ marrow cultures. Blocking sIL-6R signaling with sgp130 (soluble glycoprotein 130 receptor) inhibited PTH-dependent hematopoietic cell expansion in IL-6−/− marrow. In the skeletal system, although intermittent PTH administration to IL-6+/+ and IL-6−/− mice resulted in similar anabolic actions, blocking sIL-6R significantly attenuated PTH anabolic actions. sIL-6R showed no direct effects on osteoblast proliferation or differentiation in vitro; however, it up-regulated myeloid cell expansion and production of the mesenchymal stem cell recruiting agent, TGF-β1 in the bone marrow microenvironment. Collectively, sIL-6R demonstrated orphan function and mediated PTH anabolic actions in bone in association with support of myeloid lineage cells in the hematopoietic system. 相似文献
67.
Kevin McClay Baojie Wan Yuehong Wang Sanghyun Cho Jerry Yu Bernard Santarsiero Shahila Mehboob Michael Johnson Scott Franzblau Robert Steffan 《Applied microbiology and biotechnology》2013,97(16):7151-7163
Two bacterial hosts expressing cloned aromatic oxygenases were used to catalyze the oxidation and polymerization of indole and related substrates, creating mixtures of indigoid compounds comprised of novel dimers and trimers. Crude extracts and purified compounds were tested for their ability to inhibit the growth of Gram-positive organisms, in general, and Mycobacterium tuberculosis (TB), in particular. Of the 74 compounds tested against M. tuberculosis, ~66 % had minimum inhibitory concentrations (MIC) of 5 μg/ml or less. The most effective antibiotic found was designated SAB-P1, a heterodimer of indole and anthranil, which had a MIC of 0.16 μg/ml, and did not inhibit kidney cells (IC50) at concentrations of >8 μg/ml. Combinatorial biocatalysis was used to create a series of halogenated derivatives of SAB-P1 with a wider therapeutic window. None of the derivatives had MIC values that were superior to SAB-P1, but some had a wider therapeutic window because of decreased kidney cell toxicity. Generally, the indigoid dimers that were effective against TB appeared to be specific for TB. Some of the trimers generated, however, had a broader spectrum of activity inhibiting not only TB (MIC?=?1.1 μg/ml) but also the growth of Mycobacterium smegmatis MC2 155, Bacillus cereus, Enterococcus faecalis, Staphylococcus epidermidis, Bacillus subtilis 168, and Clostridium acetobutylicum. The structure of two of the novel dimers (SAB-C4 and SAB-P1) and a trimer (SAB-R1) were solved using X-ray crystallography. 相似文献
68.
Kyoung Joo Cho Hyun Woo Kim So Yeong Cheon Jong Eun Lee Gyung Whan Kim 《Biochemical and biophysical research communications》2013
Apoptosis signal-regulating kinase-1 (ASK1), an early signaling element in the cell death pathway, has been suggested to participate in the pathology of neurodegenerative diseases, which may be associated with environmental factors that impact the diseases. Although it is not entirely elucidated, 3-nitropropionic acid (3-NP) provokes mitochondrial dysfunction and selectively forms striatal lesions similar to those found in Huntington’s disease. The current study investigated whether ASK1 is involved in striatal pathology following chronic systemic infusion of 3-NP. The results show that ASK1 acts as a primary mediator of there active oxygen species (ROS) cell death signal cascade in the 3-NP-damaged striatal region by disrupting the positive feedback cycle. In 3-NP-infused striatal lesions, ROS increased ASK1. Superoxide dismutase transgenic (SOD-tg) mice reduced ASK1by scavenging ROS, and reduction of ASK1leads to a reduction in cell death. However, ASK1 down-regulation in 3-NP infusion mice also decreased striatal cell death without scavenging ROS. In contrast decreasing cell death by si-ASK1 treatment along with 3-NP in both SOD tg and wild-type mice (wt), cell death rebounded when ASK1 peptide was added to SOD tg mice. The present study suggests that ROS-inducing ASK1 may be an important step in the pathogenesis of 3-NP infused striatal lesions in murine brains. 相似文献
69.
Sunglim Cho Miriam Lee Youngsoo Jun 《Biochemical and biophysical research communications》2013,430(2):787-792
Aberrantly folded proteins in the endoplasmic reticulum (ER) are rapidly removed into the cytosol for degradation by the proteasome via an evolutionarily conserved process termed ER-associated protein degradation (ERAD). ERAD of a subset of proteins requires Derlin-1 for dislocation into the cytosol; however, the molecular function of Derlin-1 remains unclear. Human cytomegalovirus US11 exploits Derlin-1-dependent ERAD to degrade major histocompatibility complex class I (MHC-I) molecules for immune evasion. Because US11 binds to both MHC-I molecules and Derlin-1 via its luminal and transmembrane domains (TMDs), respectively, the major role of US11 has been proposed to simply be delivery of MHC-I molecules to Derlin-1. Here, we directly tested this proposal by generating a hybrid MHC-I molecule, which contains the US11 TMD, and thus can associate with Derlin-1 in the absence of US11. Intriguingly, this MHC-I hybrid was rapidly degraded in a Derlin-1- and proteasome-dependent manner. Similarly, the vesicular stomatitis virus G protein, otherwise expressed at the cell surface, was degraded via Derlin-1-dependent ERAD when its TMD was replaced with that of US11. Thus, forced interaction of cell surface proteins with Derlin-1 is sufficient to induce their degradation via ERAD. Taken together, these results suggest that the main role of US11 is to recruit MHC-I molecules to Derlin-1, which then mediates the dislocation of MHC-I molecules into the cytosol for degradation. 相似文献
70.
Jun Park Yong Hwa Jo Chang Hoon Cho Wonchae Choe Insug Kang Hyung Hwan Baik Kyung-Sik Yoon 《Biochemical and biophysical research communications》2013,430(1):429-435
DNA DSBs are induced by IR or radiomimetic drugs such as doxorubicin. It has been indicated that cells from ataxia-telangiectasia patients are highly sensitive to radiation due to defects in DNA repair, but whether they have impairment in apoptosis has not been fully elucidated. A-T cells showed increased sensitivity to high levels of DNA damage, however, they were more resistant to low doses. Normal cells treated with combination of KU55933, a specific ATM kinase inhibitor, and doxorubicin showed increased resistance as they do in a similar manner to A-T cells. A-T cells have higher viability but more DNA breaks, in addition, the activations of p53 and apoptotic proteins (Bax and caspase-3) were deficient, but Akt expression was enhanced. A-T cells subsequently underwent premature senescence after treatment with a low dose of doxorubicin, which was confirmed by G2 accumulation, senescent morphology, and SA-β-gal positive until 15 days repair incubation. Finally, A-T cells are radio-resistant at low doses due to its defectiveness in detecting DNA damage and apoptosis, but the accumulation of DNA damage leads cells to premature senescence. 相似文献