富含鸟嘌呤的DNA/RNA序列可以通过Hoogsteen氢键折叠成非传统的G-四链体（简称G4）结构。虽然G4 RNA的动态结构及其与G4 RNA解旋酶的相互作用在生命过程中发挥着重要的调节作用，但是G4 RNA的动态折叠和打开过程以及G4 RNA与解旋酶相互作用的微观分子机理仍未得到阐明。单分子技术的发展为实时研究生物大分子结构变化和相互作用提供了有效方法。本项目拟选取与动物癌症发生和植物抗逆过程相关的G4 RNA和eIF4A解旋酶为研究对象，利用单分子荧光共振能量转移（smFRET）技术，深入研究G4 RNA折叠和去折叠的路径，内外条件对G4 RNA结构动力学的影响，eIF4A结合并解旋G4 RNA的分子过程，以及G4 RNA对eIF4A结构和行为的影响。本项目的实施和完成将为理解G4 RNA对生命过程的调节机制提供科学依据，也为癌症治疗和抵抗非生物逆境胁迫植物品种的设计提供理论参考。

Guanine (G)-rich sequences in DNA/RNA can fold into non-canonical G-quadruplex (G4) structures by Hoogsteen hydrogen bonding. Although G4 RNA structural dynamics and its interaction with G4 RNA helicases are well known to play essential regulatory roles in various life processes. Unfortunately, the microscopic molecular mechanisms of the dynamic folding and unfolding of G4 RNA structure as well as its interaction mechanism with G4 RNA helicases unexplored yet. Again, it warrants to mentioning that the advancements in single-molecule imaging techniques provide efficient methods for exploring structural dynamics and macromolecular interactions in real time. Therefore, the present proposal was designed with aims to study the folding and unfolding mechanism of G4 RNA, effect of internal as well as external stresses on structural dynamics of G4 RNA, the process of eIF4A binding and unwinding of G4 RNA, and the impact of G4 RNA on eIF4A structure and behaviors by selecting G4 RNA and eIF4A helicase, which are known to related with cancer in animal and plant response to stress, by using single-molecule fluorescence resonance energy transfer (smFRET) method. The expected outcomes of this project will not only provide a basis for understanding the regulatory mechanism of G4 RNA during life processes but also will provide a theoretical foundation for the treatment of cancer as well as in the development of plant varieties resistant to abiotic stresses.