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941.
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RNA interference (RNAi) is a process whereby short-interfering RNAs (siRNA) silence gene expression in a sequence-specific manner. We have screened a chemical library of substituted dihydropteridinones and identified a nontoxic, cell permeable, and reversible inhibitor of the RNAi pathway in human cells. Biochemical and fluorescence resonance-energy transfer experiments demonstrated that one of the compounds, named ATPA-18, inhibited siRNA unwinding that occurred within 6 hr of siRNA transfection. Extracts prepared from ATPA-18-treated cells also exhibited a decrease in target RNA cleavage by activated RNA-induced silencing complex (RISC*). Interestingly, when activated RISC*, which harbors unwound antisense siRNA, was treated with ATPA-18 in vitro, target RNA cleavage was not affected, indicating that this compound inhibited siRNA unwinding or steps upstream of unwinding in the RNAi pathway. Our results also establish the timing of siRNA unwinding and show that siRNA helicase activity is required for RNAi. ATPA-18 analogs will therefore provide a new class of small molecules for studying RNAi mechanisms in a variety of model organisms and deciphering in vivo genetic functions through reverse genetics. 相似文献
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Adeva B Becker U Becker-Szendy R Berdugo J Boehm A Branson JG Burger JD Capell M Cerrada M Chang CC Chang YH Chen HS Chen M Chen ML Chen MY Deffur E Demarteau M Dong BZ Duinker P Fesefeldt HS Fong D Fukushima M Garrido L Han RD Harting D Herten G Ho MC Hueser D Hussain M Ilyas MM Jiang DZ Krenz W Kuijer P Li QZ Linnhoefer D Luckey D Luit EJ Mana C Marquina MA Martinez M Massaro GG Mnich J Mount R Nadeem K Newman H Pohl M Poschmann FP Rau RR Rodriguez S Rohde M Rubio JA Rykaczewski H Salicio J 《Physical review letters》1985,54(16):1750-1753
946.
Synthesis of a new chiral N,N,N-tridentate pyridinebisimidazoline ligand library and its application in Ru-catalyzed asymmetric epoxidation 总被引:1,自引:0,他引:1
Bhor S Anilkumar G Tse MK Klawonn M Döbler C Bitterlich B Grotevendt A Beller M 《Organic letters》2005,7(16):3393-3396
A small ligand library of chiral tridentate N,N,N-pyridinebisimidazolines have been synthesized for the first time. This new class of ligands can be easily tuned and synthesized on multi g-scale. The usefulness of the ligands is shown in the ruthenium-catalyzed asymmetric epoxidation with hydrogen peroxide as oxidant. Excellent yields (>99%) and good enantioselectivities (up to 71% ee) have been obtained for the epoxidation of aromatic olefins. [reaction: see text] 相似文献
947.
Evaluation of sample extraction methods for proteomics analysis of green algae Chlorella vulgaris
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Many protein extraction methods have been developed for plant proteome analysis but information is limited on the optimal protein extraction method from algae species. This study evaluated four protein extraction methods, i.e. direct lysis buffer method, TCA‐acetone method, phenol method, and phenol/TCA‐acetone method, using green algae Chlorella vulgaris for proteome analysis. The data presented showed that phenol/TCA‐acetone method was superior to the other three tested methods with regards to shotgun proteomics. Proteins identified using shotgun proteomics were validated using sequential window acquisition of all theoretical fragment‐ion spectra (SWATH) technique. Additionally, SWATH provides protein quantitation information from different methods and protein abundance using different protein extraction methods was evaluated. These results highlight the importance of green algae protein extraction method for subsequent MS analysis and identification. 相似文献
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949.
Indolylbenzimidazole‐based ligands catalyze the coupling of arylboronic acids with aryl halides
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A novel class of compounds bearing indole and benzimidazole rings was designed and easily synthesized from 2‐indolecarboxylic acid and o‐phenylenediamine. The catalytic system derived from a 2‐indolylbenzimidazole‐based ligand and Pd(OAc)2 in situ could lead to complete conversion of aryl bromides at 0.5 mol% Pd loading under mild reaction conditions. In the presence of a catalyst, sterically hindered biaryls were selectively generated in excellent yields by adjusting reaction parameters through the coupling of arylboronic acids with aryl halides. The efficiency of this reaction was demonstrated by its compatibility with various functional groups. 相似文献
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