Design Strategy for DNA Rotaxanes with a Mechanically Reinforced PX100 Axle

摘要

Rotaxanes are interlocked molecular architectures that can be perceived as simple mechanical devices.A macrocycle that is threaded onto an axle and is deterred from dethreading by bulky stoppers can move translationally along the vector of the axle as well as rotate around it. To ensure that these molecular assemblies can carry out directional mechanical motion, the respective components require sufficient dimensional stability, or stiffness, over the entire working space. In case of rotaxanes, it is primarily the axle that needs to exist as a non-deformable unit to efficiently convert the microscopic movement of the macrocycle into mechanical energy and to employ it for power transmission, otherwise the momentum of the moving macrocycle simply leads to a deformation of the axle, and thus cannot be further employed. We have recently described a DNA rotaxane that has a translational amplitude of about 100 base pairs (bp). In a double-stranded DNA, however, the length of persistence of approximately 130 bp is too short to meet the required mechanical stability along the dumbbell axle.