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171.
172.
Johnson EC Feher VA Peng JW Moore JM Williamson JR 《Journal of the American Chemical Society》2003,125(51):15724-15725
Several NMR screening techniques have been developed in recent years to aid in the identification of lead drug compounds. These NMR methods have traditionally been used for protein targets, and here we examine their applicability for an RNA target. We used the SHAPES compound library to test three different NMR screening methodologies: the saturation transfer difference (STD), the 2D trNOESY, and the WaterLOGSY experiments. We found that the WaterLOGSY experiment was the most sensitive method for our RNA target, the P4P6 domain of the Tetrahymena thermophila Group I intron. Using the WaterLOGSY experiment, we found that 23 of the 112 SHAPES compounds interact with P4P6. To identify which of these 23 hits bind through nonspecific interactions, we counterscreened with a linear duplex RNA control and identified one of the SHAPES compounds as interacting with P4P6 specifically. We thus demonstrated that the WaterLOGSY experiment in combination with the SHAPES compound library can be used to efficiently find RNA binding lead compounds. 相似文献
173.
关于聚合物非晶态X衍射表征函数的探讨 总被引:1,自引:1,他引:1
<正> 目前许多学者已采用计算机X衍射分峰法对具有较复杂结构的结晶聚合物进行研究.这个方法的核心是数学模型,即反映晶态与非晶态的X衍射峰峰形规律的表征函数.它对研究结果的可靠性、精确度有直接的影响.Hindeleh与Johnson等人提出的三次多项式及其它形式,不能使样品的计算的衍射曲线与实验的衍射曲线相拟合,误差大.说明表征非晶态X衍射的数学模型还存在问题,分峰法还不完善.因此,我们认为有必要对非晶态表征函数进行探讨.本文提出了两个非晶态表征函数,并应用于聚丙烯结构分析, 相似文献
174.
SYNTHESIS OF HYPERBRANCHED CONJUGATIVE POLY(ARYLENEETHYNYLENE)S BY ALKYNE POLYCYCLOTRIMERIZATION 总被引:2,自引:0,他引:2
A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%). 相似文献
175.
A new model was proposed to predict the adsorption equilibrium of mixtures composed of supercritical gases. The adsorbed phase was visualized as a two-dimensional nonideal compressed gas. Pore size distribution was used to describe the energetic heterogeneity of the surface, and the two-dimensional virial equation was used as the local adsorption isotherm. The new model obtained is thermodynamically rigorous because it reduces to Henry's law as pressure approaches zero. The prediction performance of the new model was verified and compared with other models using the experimental data of a ternary mixture of CH4/N2/H2 and two binary mixtures of CH4/C2H4 and CH4/N2. Better performance was shown for all systems tested. 相似文献
176.
运用三足四齿配体三(2-甲基吡啶)胺(TPA)或三(2-甲基苯丙咪唑)胺(TBA),得到两个双核铁(III)配合物,[Fe2L2(μ2-O)(μ2-p-NH2-C6H4COO)]3+
(L = TPA, 1 和 L = TBA,
2)。两个配合物均为单斜晶系,空间群为P2(1)/c.晶胞参数 1: a =
1.4529(4), b = 1.6622(5), c = 2.0625(6) nm, β= 100.327(5)º,
V = 4.900(3) nm3, z = 4, F(000) = 2344, 分子量Mr = 1142.91, Dc
= 1.549 g/cm3, R1 = 0.0544,
R2 = 0.0962. 2: a = 1.3378(4), b = 2.1174(7), c =
2.4351(7) nm, β= 97.315(6)º, V = 6.842(4) nm3,
z = 4, F (000) = 3116, 分子量Mr = 1505.08, Dc
= 1.444 g/cm3, R1 = 0.0793, R2 = 0.1623. 在两个双核铁(III)配合物中,中心的三价铁和配体TPA或TBA上的四个氮原子和两个氧原子通过不同的桥形成一个畸变的八面体构型。 相似文献
177.
A novel terminal hydroxide containing dinuclear alumoxane LAl(OH)OAlL(OCH=N-tBu) (3; L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3) was prepared by treatment of aluminum dihydride LAlH2 (1) and tert-butyl isocyanate in the presence of trace amounts of water and alternatively from 1 and LAlH(OCH=N-tBu) (2) with water. Compound 2 was obtained from the reaction of 1 and tert-butyl isocyanate. 相似文献
178.
Enzymatic oligosaccharide synthesis using recombinant glycosyltransferases is able to overcome the difficulties associated with chemical methods. Nonetheless, sugar nucleotide regeneration cycles are necessary for the glycosylation. The multistep enzyme reaction can be efficiently carried out on superbeads that are prepared by immobilizing multienzyme mixtures on bead support through fused binding domains. 相似文献
179.
180.