A Novel Strategy for Active Control of DNA Recognition by External Stimulates -Peptide Ribonucleic Acids (PRNA)-

在为下一代功能材料开发核酸模型的过程中，如果能够实现一种新型的核酸模型对核酸的识别控制和/或可逆识别控制，就可以实现对外界刺激和/或因子的功能的动态表达/抑制。因此，这项工作的主题是外部因素和/或刺激对核酸识别的动态和可逆控制，这是传统的基于核酸结构的核酸模型化合物无法实现的。在这项工作中，着眼于可逆DNA识别依赖的重要性，作者发现了通过改变多肽核糖核酸(PRNAs)的pH体系来控制可逆DNA识别的新策略。作者建立了一系列以腺嘌呤、胞嘧啶、次黄嘌呤和尿嘧啶为识别位点的PRNA单体的合成路线。这使我们能够完全扩展RAN…更多可用的PRNA单体。作者进一步证明，新合成的Fmoc保护的PRNA单体与标准的固相肽合成方案兼容，可以制备具有嘌呤-嘧啶混合序列的寡聚PRNAs。这证明了嘧啶-嘌呤混合序列的方向转换。在这项研究和之前的研究中，我们提出了一种新的方法和有效的工具，通过使用外部试剂来控制DNA/RNA识别。这一策略使用了新的核酸类似物，即-肽核糖核酸(^-PRNAs)作为识别部分，它具有由外部因素触发的内置开关。在高嘧啶和嘧啶混合序列的情况下，核糖的顺式-2‘，3’-二醇的硼酸酯的形成以及5‘-酰胺质子和2-羰基氧之间的氢键作用起着外部和内部开关的作用。这些研究的结果令人鼓舞，表明^-PRNA与互补的寡核苷酸形成稳定的杂交复合体，这些复合体在加入硼砂或硼酸后很容易解离。此外，还考察了肽骨架的手性对PRNA的结构和DNA识别行为的影响。加入硼砂作为外控因子，可使L-谷氨酸和D-0-谷氨酸主链上的PRNA单体和寡聚体的取向容易从反向向同步。齐聚促进了分子间的协同取向转换和硼酸盐的形成。此外，D-、L-PRNA寡聚体相互诱导出不同的高阶结构。当然，D-、L-核糖核酸分别确定为右旋和左旋螺旋结构。右旋卷曲的D-PRNA与互补DNA的络合物比L-PRNA与DNA的络合物更稳定，这表明相同的右旋螺旋结构的D-PRNA与DNA形成的络合物是更好的。然后，展示了嘧啶-嘌呤混合序列PRNA识别DNA的开关。与天然DNA相比，混合序列的PRNA与互补DNA形成更稳定的复合体。此外，通过2‘，3’-二醇形成的硼酸盐和5‘-酰胺质子与嘧啶核苷2位上的羰基氧形成氢键，使碱基取向从反向向同步转变，实现了DNA识别PRNA的开关开关。进一步提高了核酸模型的识别选择性和识别能力。PRNA与互补DNA形成更稳定的复合体，与互补DNA的结合具有序列特异性，这是首次在多种生理条件下对核酸进行可逆识别的研究。这些结果将展示一种为下一代设计反义分子的策略，该反义分子在细胞和/或细胞核中通过环境刺激做出反应。较少

In the development of nucleic acid models for the next generation of functional materials, if the recognition control and/or reversible recognition control of nucleic acids by a novel nucleic acid model could be achieved, the dynamic expression/suppression of functions as to external stimulates and/or factor could be materialized. Thus, the subject of this work was dynamic and reversible control of nucleic acid recognition by an external factor and/or stimulate, which cannot be realized by the conventional nucleic acid model compounds based on a structure of nucleic acids. In this work, focusing on the importance of reversible DNA recognition dependent, the author found the novel strategy for reversible DNA recognition control by change of pH system with peptide ribonucleic acids (PRNAs). The author established the synthetic routes to a series of PRNA monomers, carrying adenine, cytosine, hypoxanthine, and uracil nucleobases as recognition sites. This enabled us to fully expand the ran … More ge of available PRNA monomers. The author further demonstrated that the newly synthesized Fmoc-protected PRNA monomers are compatible with the standard solid-phase peptide synthesis protocol, and oligomeric PRNAs with purine-pyrimidine mixed sequences can be prepared. It was demonstrated that the orientation switching of pyrimidine-purine mixed sequence PRNAs. In this and preceding studies, we have proposed a new methodology and effective tools for controlling DNA/RNA recognition through the use of an external agent. This-strategy employs novel nucleic acid analogues, i.e. □-peptide ribonucleic acids (^-PRNAs), as the recognition moiety which has a built-in switch triggered by an external factor. In the cases of not only homo-pyrimidine PRNAs but also pyrimidine-purine mixed sequenced PRNAs, the formation of a borate ester of the ribose's cis-2',3'-diol and the simultaneous hydrogen-bonding interaction between the 5'-amide proton and the 2-carbonyl oxygen act as the external and internal switching devices. The results obtained in these studies are encouraging, demonstrating that ^-PRNA form stable hybrid complexes with the complementary oligonucleotides, which are readily dissociated upon addition of borax or boric acid. Moreover, it was investigated that the chirality effect of peptide backbone upon the structure and DNA recognition behavior of PRNA. The orientation of PRNA monomers and oligomers tethered to L-and D-0-glutamic acid backbone could readily be switched from anti to syn by adding borax as an external controlling factor. The cooperative orientation switching and borate formation were enhanced by oligomerization. Furthermore, D-, L-PRNA oligomers were induced different higher-order structure each other. Certainly, D-, L-PRNA were determined right-handed and left-handed coiled structure respectively. The complex of right-handed coiled D-PRNA with complementary DNA was more stable than that of L-PRNA with DNA to indicate that the complexation, which was formed between same right-handed coiled structures of D-PRNA and DNA, was preferable. Then, the on-off switching of DNA recognition with pyrimidine-purine mixed sequence PRNA was demonstrated. PRNA with mixed sequence formed more stable complex with complementary DNA than natural DNA. Moreover, it was revealed that the on-off switching of the DNA recognition of PRNA could be materialized by the synergistic puckering change through borate formation of 2',3'-diol and base orientation switching from anti to syn through the hydrogen bonding formation between 5'-amide proton and carbonyl oxygen at 2 position of pyrimidine nucleoside. Furthermore, nucleic acid models were improved the recognition selectivity as well as its recognition ability. PRNA formed a more stable complex with complementary DNA and binding of PRNA with complementary DNA was sequence specific.This study was the first work for reversible nucleic acid recognition in the rage of physiological condition. These results will demonstrate a strategy for designing the antisense molecule for the next generation, which reacts by environmental stimulation in cell and/or nucleus. Less