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核酸的化学修饰是反义寡核苷酸分子成药的关键技术,本文以相应的2’-氟阿拉伯糖尿苷(2’-F-ara U)及2’-氟尿苷(2’-F-r U)为起点,通过在糖基的4’-位引入2-甲氧乙氧基(MOE),合成了新的单体2’-F-4’-C-MOE-ara U及其差向异构体2’-F-4’-C-MOE-r U,并将它们转化为相应的亚磷酰胺,用于所需DNA序列的合成。它们对于ds DNA和DNA-RNA双螺旋的热稳定性的影响显示,与2’-F-4’-C-MOE-r U及2’-F-ara U修饰的寡核苷酸相比,2’-F-4’-C-MOE-ara U修饰,特别是在5’-嘧啶-嘌呤-3’(5’-pyrimidine-purine-3’)步序上形成C-H…F-C假氢键时,可显著增强寡核苷酸对互补RNA的亲和力,并能够保持对互补DNA的亲和力。同时,2’-F-4’-C-MOE-ara U修饰后的寡核苷酸对完全配对的RNA/DNA单链均具有良好的结合特异性;而2’-F-4’-C-MOE-r U仅对互补RNA具有较好的杂交能力。不过,3’-末端2’-F-4’-C-MOE-ara U修饰的寡核苷酸对核酸酶水解的稳定性却低于2’-F-4’-C-MOE-r U修饰。这些结果表明了在2’-F-ANA单元上进一步引入4’-位修饰的可行性,以及2’-F取代单体对于双螺旋结构的稳定性具有显著影响,为进一步的核酸化学修饰和反义核酸药物的开发提供了新的技术支持。
The chemical modification of nucleic acid is the key technology of antisense oligonucleotide molecules. In this paper, the corresponding 2’-F-ara U and 2’-FrU ), A new monomeric 2’-F-4’-C-MOE-ara U and its epimer were synthesized by introducing 2-methoxyethoxy (MOE) into the 4’- The constructs 2’-F-4’-C-MOE-r U and converts them to the corresponding phosphoramidites for the synthesis of the desired DNA sequence. Their effect on the thermostability of ds DNA and DNA-RNA duplexes shows that compared to 2’-F-4’-C-MOE-rU and 2’-F-araU modified oligonucleotides, 2’-F-4’-C-MOE-ara U modifications, especially when CH ... FC pseudo hydrogen bonds are formed on the 5’-pyrimidine-purine-3 ’ , Can significantly enhance the affinity of the oligonucleotide for the complementary RNA and maintain the affinity for the complementary DNA. Meanwhile, the 2’-F-4’-C-MOE-ara U modified oligonucleotide has good binding specificity for the fully paired RNA / DNA single strand, while the 2’-F-4’-C -MOE-r U has good hybridization ability only to complementary RNA. However, the 3’-end 2’-F-4’-C-MOE-ara U modified oligonucleotide has less stability to nuclease hydrolysis than 2’-F-4’-C-MOE-r U Modification. These results demonstrate the feasibility of further introduction of 4’-position modifications on the 2’-F-ANA units and the 2’-F substitution of monomers have a significant effect on the stability of the duplex structure for further nucleic acid chemical modification and Antisense nucleic acid drug development has provided new technical support.