排序方式: 共有210条查询结果,搜索用时 0 毫秒
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Sirinakis G Clapier CR Gao Y Viswanathan R Cairns BR Zhang Y 《The EMBO journal》2011,30(12):2364-2372
ATP-dependent chromatin remodelling complexes use the energy of ATP hydrolysis to reposition and reconfigure nucleosomes. Despite their diverse functions, all remodellers share highly conserved ATPase domains, many shown to translocate DNA. Understanding remodelling requires biophysical knowledge of the DNA translocation process: how the ATPase moves DNA and generates force, and how translocation and force generation are coupled on nucleosomes. Here, we characterize the real-time activity of a minimal RSC translocase 'motor' on bare DNA, using high-resolution optical tweezers and a 'tethered' translocase system. We observe on dsDNA a processivity of ~35 bp, a speed of ~25 bp/s, and a step size of 2.0 (±0.4, s.e.m.) bp. Surprisingly, the motor is capable of moving against high force, up to 30 pN, making it one of the most force-resistant motors known. We also provide evidence for DNA 'buckling' at initiation. These observations reveal the ATPase as a powerful DNA translocating motor capable of disrupting DNA-histone interactions by mechanical force. 相似文献
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Andrew C. Tolonen Trevor R. Zuroff Mohandass Ramya Magali Boutard Tristan Cerisy Wayne R. Curtis 《Applied and environmental microbiology》2015,81(16):5440-5448
Novel processing strategies for hydrolysis and fermentation of lignocellulosic biomass in a single reactor offer large potential cost savings for production of biocommodities and biofuels. One critical challenge is retaining high enzyme production in the presence of elevated product titers. Toward this goal, the cellulolytic, ethanol-producing bacterium Clostridium phytofermentans was adapted to increased ethanol concentrations. The resulting ethanol-tolerant (ET) strain has nearly doubled ethanol tolerance relative to the wild-type level but also reduced ethanol yield and growth at low ethanol concentrations. The genome of the ET strain has coding changes in proteins involved in membrane biosynthesis, the Rnf complex, cation homeostasis, gene regulation, and ethanol production. In particular, purification of the mutant bifunctional acetaldehyde coenzyme A (CoA)/alcohol dehydrogenase showed that a G609D variant abolished its activities, including ethanol formation. Heterologous expression of Zymomonas mobilis pyruvate decarboxylase and alcohol dehydrogenase in the ET strain increased cellulose consumption and restored ethanol production, demonstrating how metabolic engineering can be used to overcome disadvantageous mutations incurred during adaptation to ethanol. We discuss how genetic changes in the ET strain reveal novel potential strategies for improving microbial solvent tolerance. 相似文献
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Sathishkumar N Sathiyamoorthy S Ramya M Yang DU Lee HN Yang DC 《Journal of enzyme inhibition and medicinal chemistry》2012,27(5):685-692
Anti-apoptotic proteins such as BCL-2, BCL-XL and MCL-1 bind with pro-apoptotic proteins to induce apoptosis mechanism. BCL-2 family proteins are key regulators of apoptosis process. Over expression of these anti-apoptotic proteins lead to several cancers by preventing apoptosis. A number of studies revealed that ginseng derivatives reduce tumor growth. Ginseng, the most valuable medicinal herb found in eastern Asia belongs to Araliaceae family. In this study, docking simulations were performed for anti-apoptotic proteins with several ginsenosides from Panax ginseng. Our finding shows ginsenosides Rf, Rg1, Rg3 and Rh2 have more binding affinity with BCL-2, BCL-XL and MCL-1 and other ginsenosides also interact with each anti-apoptotic proteins. Therefore, ginseng derivatives represent a novel class of potent inhibitors and could be used for cancer chemotherapy. 相似文献
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Padavala Ajay Babu Suma Sree Puppala Satyavarapu Lakshmi Aswini Metta Ramya Vani Chinta Narasimha Kumar Tallapragada Prasanna 《Bioinformation》2008,3(3):142-143
Marine compound database consists of marine natural products and chemical entities, collected from various literature sources,
which are known to possess bioactivity against human diseases. The database is constructed using html code. The 12 categories
of 182 compounds are provided with the source, compound name, 2-dimensional structure, bioactivity and clinical trial
information. The database is freely available online and can be accessed at
http://www.progenebio.in/mcdb/index.htm 相似文献