ＤＮＡナノテクノロジーを基盤とした生体分子反応の直接１分子観察と応用

(1)用于蛋白质光调控的可远程控制的DNA纳米胶囊。设计并构建了一种70 nm×10 nm×10 nm的3D DNA胶囊，其中包含一个用于携带靶分子的小纳米空间。该纳米结构已成功组装完成，并通过原子力显微镜进行了验证。本研究选择caspase-3作为靶点，研究其对癌细胞的诱导凋亡作用。Caspase-3标记的纳米胶囊将进一步进入细胞系统。利用AFM观察了标记前后笼状纳米胶囊的光诱导裂解情况。(2)直接显示单个DNA折纸上的旋转运动利用DNA光开关开发了一种新型的基于DNA折纸的纳米机械装置。一种由两个双交叉分子组装而成的矩形DNA折纸，两个双交叉分子通过刚性连接物相连：一条用低聚亚苯-乙烯修饰的核酸短链，其中一个DX分子位于DNA碎片的表面作为指针。构建了纳米结构，并用原子力显微镜进行了验证。将两对含偶氮苯分子的光响应寡核苷酸分别引入DX指针和DNA瓷砖支架中。通过切换不同波长的光照射，可以驱动DX指针以时钟指针的方式在DNA瓷砖上旋转。此外，利用高速原子力显微镜直观地显示了DX指针在单个DNA瓷砖上的可逆旋转运动。

(1) Remotely controllable DNA nanocapsule for the delivery of protein by photo regulation.A 70 nm × 10 nm × 10 nm 3D DNA capsule was designed and constructed, which containing a small nanospace inside employed for carrying target molecules. The nanostructure has been successfully assembled and confirmed by AFM. Here caspase-3 was chosen as target for delivery, which can induce the apoptosis of cancer cells. The expression of the protein has been successfully carried out and the activity also confirmed.The caspase-3 labeled nanocapsule will be further introduced into the cell system. The photoinduced cleavage of caged nanocapsule has been examined by AFM before and after the labeling.(2) Direct visualization of rotational motions on a single DNA origamiA novel nanomechanical device based on DNA origami was developed by empoying DNA photoswitches. A rectangular DNA origami assembled with two double-crossover molecules connected by a rigid linker: a short nucleic acid strand modified with oligophenylene-ethylene, in which one of the DX molecules was located on the surface of DNA tile as a pointer. The nanostructures were constructed and confirmed by AFM. Two pairs of photoresponsive oligonucleotides containing azobenzene molecules were introduced into DX pointer and DNA tile scaffold separately. By switching the photoirradiation with different wavelengths, the DX pointer can be driven to rotate on the DNA tile in a pointer-on-a clock fashion. Moreover, reversible rotational movement of DX pointer on single DNA tile was directly visualized using high-speed AFM.