نمونه متن انگلیسی مقاله
Nanoscale mobile devices (nanomotors) have many potential applications, such as information processing, nanoelectronic devices, biosensors, and regulation of chemical reactions and molecular assembly. Various artificial nanomotors have been reported in recent years. These motors include organic molecules,[2–5] engineered DNA constructs,[6–12] and inorganic/ protein hybrids. However, reports of autonomous synthetic nanomotors are very rare.[5, 11, 13] Autonomy is an important characteristic of cellular protein motors, which prompted us to ask whether it would be possible to design biomimetic nanomotors that continuously conduct mechanical motions powered by consumed chemical energy. Herein, we report the construction of a DNA nanomotor powered by an RNAcleaving DNA enzyme.[14–17] The motor keeps operating as long as its fuel (the RNA substrate of the DNA enzyme) is available. This DNA motor is a biomimetic nanomotor that works in the same way as natural protein motors, that is, by continuously extracting chemical energy from covalent bonds and converting this energy into mechanical motions.[18–20]
Most protein motors,[18–22] which include myosin, kinesin, and F0F1 adenosine triphosphate (ATP) synthase, possess an ATPase activity. These motors can bind to and hydrolyze ATP to form ADP, which is then released. The energy released by the chemical process of ATP hydrolysis powers protein motors and enables them to change their conformation, which results in mechanical movement. The DNA motor presented herein works in a similar way. The catalytic domain of the DNA can bind to a DNA–RNA chimera substrate, cleave this substrate into two short fragments, and then release the pieces. This process leads the DNA motor to change its conformation, which generates nanoscale motions. We demonstrated the motion of the DNA motor by using fluorescence resonance energy transfer (FRET) techniques and monitored the autonomous cycling of the motor by observing substrate cleavage.