| 研究実績の概要 |
DNA topoisomerases (Topos) regulate the DNA topology such as overwinding or underwinding that arises due to the intertwined nature of the double helical structure. These enzymes also play an important role in replication, transcription, recombination, and chromosome condensation and segregation. This enzyme is of great interest as a potential target for the development of anticancer drugs. There have been several Topo-inhibitors developed and their functions were evaluated. However, the mechanism of action of these anticancer drug molecules is not well known. Thus, to understand the Topos reactions and the mechanism of the inhibition, it is necessary to develop a versatile method.
In this work, we have developed a novel method by the combination of DNA origami and high-speed atomic force microscopy (HS-AFM) for the screening of Topo-inhibitors. As for the target structures for the Topo reactions, we have constructed topologically interlocked DNA catenane- and rotaxane-like structures inside a DNA origami frame. The formation of the DNA origami frame and the insertion of the catenane- and rotaxane-like structures were successfully characterized. To increase the stability of these functional structures, the nicks in these structures were sealed by using T4 DNA ligase. The ligation was also confirmed by the thermal treatment of these structures, where the ligated samples were stable at high temperature incubation while the unligated samples failed to keep the folded structures. The Topo reaction and the function of Topo-inhibitors are under investigation.
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