排序方式: 共有47条查询结果,搜索用时 15 毫秒
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Lee S Jia B Pham BP Shao Y Kwak JM Cheong GW 《Extremophiles : life under extreme conditions》2012,16(1):87-93
Sarcosine oxidase (SOX) catalyzes the oxidation of the methyl group in sarcosine and transfer of the oxidized methyl group
into the one-carbon metabolic pool. Here, we separately cloned and expressed α and β subunit of SOX from Thermococcus kodakarensis KOD1 (TkSOX) in Escherichia coli and the recombinant proteins were purified to homogeneity. Gel filtration chromatography and transmission electron microscopy
analysis showed that the α subunit formed a dimeric structure and behaved as an NADH dehydrogenase; β subunit was a tetramer
that had sarcosine oxidase and l-proline dehydrogenase activity. The TkSOX complex assembled into the hetero-octameric (αβ)4 form and had NADH dehydrogenase activity. Gold-label analysis indicated that α and β subunits were oriented in the alternative
form. Based on these results, we suggested that TkSOX was a multifunctional enzyme and that each subunit and (αβ)4 complex may separately exist as a function enzyme in different conditions. 相似文献
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Sangmin Lee Baolei Jia Jinliang Liu Bang Phuong Pham Jae Myeong Kwak Yuan Hu Xuan Gang-Won Cheong 《PloS one》2015,10(5)
Peroxiredoxins (Prxs) act against hydrogen peroxide (H2O2), organic peroxides, and peroxynitrite. Thermococcus kodakaraensis KOD1, an anaerobic archaeon, contains many antioxidant proteins, including three Prxs (Tk0537, Tk0815, and Tk1055). Only Tk0537 has been found to be induced in response to heat, osmotic, and oxidative stress. Tk0537 was found to belong to a 1-Cys Prx6 subfamily based on sequence analysis and was named 1-Cys TkPrx. Using gel filtration chromatography, electron microscopy, and blue-native polyacrylamide gel electrophoresis, we observed that 1-Cys TkPrx exhibits oligomeric forms with reduced peroxide reductase activity as well as decameric and dodecameric forms that can act as molecular chaperones by protecting both proteins and DNA from oxidative stress. Mutational analysis showed that a cysteine residue at the N-terminus (Cys46) was responsible for the peroxide reductase activity, and cysteine residues at the C-terminus (Cys205 and Cys211) were important for oligomerization. Based on our results, we propose that interconversion between different oligomers is important for regulating the different functions of 1-Cys TkPrx. 相似文献
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Baolei Jia Sangmin Lee Bang P. Pham Yoon Seung Cho Jae-Kyung Yang Hee-Seop Byeon Jong Cheol Kim Gang-Won Cheong 《Molecules and cells》2010,29(4):363-371
NADH oxidases (NOXs) catalyze the two-electron reduction of oxygen to H2O2 or four-electron reduction of oxygen to H2O. In this report, we show that an NADH oxidase from Thermococcus profundus (NOXtp) displays two forms: a native dimeric protein under physiological conditions and an oxidized hexameric form under
oxidative stress. Native NOXtp displays high NADH oxidase activity, and oxidized NOXtp can accelerate the aggregation of partially
unfolded proteins. The aggregates formed by NOXtp have characteristics similar to β-amyloid and Lewy bodies in neurodegenerative
diseases, including an increase of β-sheet content. Oxidized NOXtp can also bind nucleic acids and cause their degradation
by oxidizing NADH to produce H2O2. Furthermore, Escherichia coli cells expressing NOXtp are less viable than cells not expressing NOXtp after treatment with H2O2. As NOXtp shares similar features with eukaryotic cell death isozymes and life may have originated from hyperthermophiles,
we suggest that NOXtp may be an ancestor of cell death proteins. 相似文献
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Youngpyo Nam Jong-Heon Kim Minchul Seo Jae-Hong Kim Myungwon Jin Sangmin Jeon Jung-wan Seo Won-Ha Lee So Jin Bing Youngheun Jee Won Kee Lee Dong Ho Park Hyun Kook Kyoungho Suk 《The Journal of biological chemistry》2014,289(24):16773-16789
Lipocalin-2 (LCN2) plays an important role in cellular processes as diverse as cell growth, migration/invasion, differentiation, and death/survival. Furthermore, recent studies indicate that LCN2 expression and secretion by glial cells are induced by inflammatory stimuli in the central nervous system. The present study was undertaken to examine the regulation of LCN2 expression in experimental autoimmune encephalomyelitis (EAE) and to determine the role of LCN2 in the disease process. LCN2 expression was found to be strongly increased in spinal cord and secondary lymphoid tissues after EAE induction. In spinal cords astrocytes and microglia were the major cell types expressing LCN2 and its receptor 24p3R, respectively, whereas in spleens, LCN2 and 24p3R were highly expressed in neutrophils and dendritic cells, respectively. Furthermore, disease severity, inflammatory infiltration, demyelination, glial activation, the expression of inflammatory mediators, and the proliferation of MOG-specific T cells were significantly attenuated in Lcn2-deficient mice as compared with wild-type animals. Myelin oligodendrocyte glycoprotein-specific T cells in culture exhibited an increased expression of Il17a, Ifng, Rorc, and Tbet after treatment with recombinant LCN2 protein. Moreover, LCN2-treated glial cells expressed higher levels of proinflammatory cytokines, chemokines, and MMP-9. Adoptive transfer and recombinant LCN2 protein injection experiments suggested that LCN2 expression in spinal cord and peripheral immune organs contributes to EAE development. Taken together, these results imply LCN2 is a critical mediator of autoimmune inflammation and disease development in EAE and suggest that LCN2 be regarded a potential therapeutic target in multiple sclerosis. 相似文献
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Jia B Park SC Lee S Pham BP Yu R Le TL Han SW Yang JK Choi MS Baumeister W Cheong GW 《The FEBS journal》2008,275(21):5355-5366
An NADH oxidase (NOX) was cloned from the genome of Thermococcus profundus (NOXtp) by genome walking, and the encoded protein was purified to homogeneity after expression in Escherichia coli. Subsequent analyses showed that it is an FAD-containing protein with a subunit molecular mass of 49 kDa that exists as a hexamer with a native molecular mass of 300 kDa. A ring-shaped hexameric form was revealed by electron microscopic and image processing analyses. NOXtp catalyzed the oxidization of NADH and NADPH and predominantly converted O(2) to H(2)O, but not to H(2)O(2), as in the case of most other NOX enzymes. To our knowledge, this is the first example of a NOX that can produce H(2)O predominantly in a thermophilic organism. As an enzyme with two cysteine residues, NOXtp contains a cysteinyl redox center at Cys45 in addition to FAD. Mutant analysis suggests that Cys45 in NOXtp plays a key role in the four-electron reduction of O(2) to H(2)O, but not in the two-electron reduction of O(2) to H(2)O(2). 相似文献
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RelB/p52 NF-kappaB complexes rescue an early delay in mammary gland development in transgenic mice with targeted superrepressor IkappaB-alpha expression and promote carcinogenesis of the mammary gland 总被引:1,自引:0,他引:1 下载免费PDF全文
Demicco EG Kavanagh KT Romieu-Mourez R Wang X Shin SR Landesman-Bollag E Seldin DC Sonenshein GE 《Molecular and cellular biology》2005,25(22):10136-10147