Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide
Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide
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DOI：
10.1016/j.bmc.2008.07.040
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发表时间：
2008-09-01
影响因子：
3.5
通讯作者：
Borbone, Nicola
中科院分区：
文献类型：
--
作者：
Coppola, Teresa;Varra, Michela;Borbone, Nicola
合成了一种新的修饰的无环核苷，即N-1-（3-羟基-2-羟甲基-2-甲基丙基）-胸苷，并将其转化为可用于寡核苷酸（ON）自动合成的构件。然后合成了一系列修饰的凝血酶结合适体（TBA），其中新的无环核苷一次一个地取代胸苷残基，并通过UV、CD、MS和H-1 NMR表征。通过凝血酶原时间测定（PT测定）和纯化纤维蛋白原凝血测定来测试所得TBA的生物活性。从结构的角度来看，几乎所有新的TBA类似物都显示出与未修饰的对应物类似的行为，能够折叠成双分子或单分子四链体结构，这取决于四链体核心中配位的单价阳离子（钠或钾）的性质。从结构和生物学数据的比较，一些重要的结构-活性关系出现，特别是当modi。阳离子参与TT环。与以前的研究一致，我们发现TBA类似物的折叠能力更受modi的影响。阳离子涉及位置4和13，而不是位置3和12。另一方面，检测到最高的抗凝血酶活性的适体含有modi。在T13或T12位上存在阳离子，因此表明通过引入无环核苷对生物活性产生的影响与结构稳定性没有紧密联系。值得注意的是，莫迪。T7处的阳离子产生比天然TBA更稳定和活性的ON。(C)2008爱思唯尔有限公司保留所有权利。
A new modified acyclic nucleoside, namely N-1-(3-hydroxy-2-hydroxymethyl-2-methylpropyl)-thymidine, was synthesized and transformed into a building block useful for oligonucleotide ( ON) automated synthesis. A series of modified thrombin binding aptamers (TBAs) in which the new acyclic nucleoside replaces, one at the time, the thymidine residues were then synthesized and characterized by UV, CD, MS, and H-1 NMR. The biological activity of the resulting TBAs was tested by Prothrombin Time assay ( PT assay) and by purified fibrinogen clotting assay. From a structural point of view, nearly all the new TBA analogues show a similar behavior as the unmodified counterpart, being able to fold into a bimolecular or monomolecular quadruplex structure depending on the nature of monovalent cations ( sodium or potassium) coordinated in the quadruplex core. From the comparison of structural and biological data, some important structure-activity relationships emerged, particularly when the modi. cation involved the TT loops. In agreement with previous studies we found that the folding ability of TBA analogues is more affected by modi. cations involving positions 4 and 13, rather than positions 3 and 12. On the other hand, the highest anti-thrombin activities were detected for aptamers containing the modi. cation at T13 or T12 positions, thus indicating that the effects produced by the introduction of the acyclic nucleoside on the biological activity are not tightly connected with structure stabilities. It is noteworthy that the modi. cation at T7 produces an ON being more stable and active than the natural TBA. (C) 2008 Elsevier Ltd. All rights reserved.