共查询到20条相似文献，搜索用时 31 毫秒
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Starai VJ Celic I Cole RN Boeke JD Escalante-Semerena JC 《Science (New York, N.Y.)》2002,298(5602):2390-2392
Acetyl-coenzyme A (CoA) synthetase (Acs) is an enzyme central to metabolism in prokaryotes and eukaryotes. Acs synthesizes acetyl CoA from acetate, adenosine triphosphate, and CoA through an acetyl-adenosine monophosphate (AMP) intermediate. Immunoblotting and mass spectrometry analysis showed that Salmonella enterica Acs enzyme activity is posttranslationally regulated by acetylation of lysine-609. Acetylation blocks synthesis of the adenylate intermediate but does not affect the thioester-forming activity of the enzyme. Activation of the acetylated enzyme requires the nicotinamide adenine dinucleotide-dependent protein deacetylase activity of the CobB Sir2 protein from S. enterica. We propose that acetylation modulates the activity of all the AMP-forming family of enzymes, including nonribosomal peptide synthetases, luciferase, and aryl- and acyl-CoA synthetases. These findings extend our knowledge of the roles of Sir2 proteins in gene silencing, chromosome stability, and cell aging and imply that lysine acetylation is a common regulatory mechanism in eukaryotes and prokaryotes. 相似文献
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Nonhistone chromosomal proteins and gene regulation 总被引：33，自引：0，他引：33
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高迁移率族核小体结合蛋白(High-mobility group nucleosome-binding proteins,HMGN)几乎存在于所有哺乳动物和多数脊椎动物的细胞核中,属于HMG蛋白家族。HMGN是现在唯一已知的特异性结合在核小体上的非组蛋白,能够改变染色质的结构、增强染色质模板的转录/复制,参与DNA复制/表达、细胞分化、器官发育及基因表达调控等细胞的生命活动。目前,HMGN包括HMGN1、HMGN2、HMGN3、HMGN4和HMGN5。研究显示,HMGN1据其所在位置的不同,有着截然不同的功能。在细胞核内,HMGN1作为一种特殊定位的生物蛋白,与核小体直接结合而调节基因的转录和影响染色质的结构;在细胞外环境,HMGN1通过toll样受体4(Toll-like receptor 4,TLR4)促进抗原提呈细胞(Antigen-presenting cells,APCs)的活化和补充,从而促进特定抗原免疫应答。警报素(Alarmins)是一种内源性介质,当机体受到危险信号刺激时,它能快速的释放到细胞外,招募并激活APCs增强特异性免疫和非特异性免疫反应。认识HMGN及其作用对其在多方面的应用有重要意义。 相似文献
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Morrison HG McArthur AG Gillin FD Aley SB Adam RD Olsen GJ Best AA Cande WZ Chen F Cipriano MJ Davids BJ Dawson SC Elmendorf HG Hehl AB Holder ME Huse SM Kim UU Lasek-Nesselquist E Manning G Nigam A Nixon JE Palm D Passamaneck NE Prabhu A Reich CI Reiner DS Samuelson J Svard SG Sogin ML 《Science (New York, N.Y.)》2007,317(5846):1921-1926
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Armache KJ Garlick JD Canzio D Narlikar GJ Kingston RE 《Science (New York, N.Y.)》2011,334(6058):977-982
Gene silencing is essential for regulating cell fate in eukaryotes. Altered chromatin architectures contribute to maintaining the silenced state in a variety of species. The silent information regulator (Sir) proteins regulate mating type in Saccharomyces cerevisiae. One of these proteins, Sir3, interacts directly with the nucleosome to help generate silenced domains. We determined the crystal structure of a complex of the yeast Sir3 BAH (bromo-associated homology) domain and the nucleosome core particle at 3.0 angstrom resolution. We see multiple molecular interactions between the protein surfaces of the nucleosome and the BAH domain that explain numerous genetic mutations. These interactions are accompanied by structural rearrangements in both the nucleosome and the BAH domain. The structure explains how covalent modifications on H4K16 and H3K79 regulate formation of a silencing complex that contains the nucleosome as a central component. 相似文献
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F-box蛋白是一类含有F-box结构域,在泛素介导的蛋白质水解过程中具有底物识别特性的蛋白质家族。这类蛋白质在细胞循环、信号传导、基因转录、雄性不育和细胞程序化死亡等多种生理过程中发挥重要作用。介绍了已知的植物F-box蛋白质的生物学功能并对F-box基因的系统进化进行了分析。 相似文献
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Vogeley L Sineshchekov OA Trivedi VD Sasaki J Spudich JL Luecke H 《Science (New York, N.Y.)》2004,306(5700):1390-1393
Microbial sensory rhodopsins are a family of membrane-embedded photoreceptors in prokaryotic and eukaryotic organisms. Structures of archaeal rhodopsins, which function as light-driven ion pumps or photosensors, have been reported. We present the structure of a eubacterial rhodopsin, which differs from those of previously characterized archaeal rhodopsins in its chromophore and cytoplasmic-side portions. Anabaena sensory rhodopsin exhibits light-induced interconversion between stable 13-cis and all-trans states of the retinylidene protein. The ratio of its cis and trans chromophore forms depends on the wavelength of illumination, thus providing a mechanism for a single protein to signal the color of light, for example, to regulate color-sensitive processes such as chromatic adaptation in photosynthesis. Its cytoplasmic half channel, highly hydrophobic in the archaeal rhodopsins, contains numerous hydrophilic residues networked by water molecules, providing a connection from the photoactive site to the cytoplasmic surface believed to interact with the receptor's soluble 14-kilodalton transducer. 相似文献
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Axonal degeneration is an active program of self-destruction that is observed in many physiological and pathological settings. In Wallerian degeneration slow (wlds) mice, Wallerian degeneration in response to axonal injury is delayed because of a mutation that results in overexpression of a chimeric protein (Wlds) composed of the ubiquitin assembly protein Ufd2a and the nicotinamide adenine dinucleotide (NAD) biosynthetic enzyme Nmnat1. We demonstrate that increased Nmnat activity is responsible for the axon-sparing activity of the Wlds protein. Furthermore, we demonstrate that SIRT1, a mammalian ortholog of Sir2, is the downstream effector of increased Nmnat activity that leads to axonal protection. These findings suggest that novel therapeutic strategies directed at increasing the supply of NAD and/or Sir2 activation may be effective for treatment of diseases characterized by axonopathy and neurodegeneration. 相似文献