Highly Processive DNA Origami Nanoscale Motors

Abstract

Biological motor proteins that convert chemical energy into controlled nanomechanical motion are essential and shared among all branches of life. Accordingly, there is considerable interest in developing synthetic analogues. Among the synthetic motors created thus far, unipedal and bipedal DNA walkers that undertake discrete steps on RNA tracks have shown the greatest promise with applications spanning from biosensing to cargo transport and cargo sorting. Nonetheless, DNA-based walkersfall short because of their limited speed, low endurance, and the lack of preferred directionality which is ultimately due to the lack of coordination between individual DNA legs. Herein, we uncover the design principles for creating autonomous, unidirectional and processive DNA motors. By taking advantage of the DNA origami three-dimensional self-assembly technique, we created a library of DNA motors that allow testing of structure-function relationships at the nanoscale. We tested the role of DNA-leg density, polyvalency, geometric distribution, and chassis rigidity. Importantly, the work reveals that the local density of DNA legs and not the absolute polyvalency, is the most important parameter contributing to effective motion. Furthermore, an anisotropic rigid chassis is necessary for unidirectional motion. This led to a rod-shaped DNA nanomotor that linearly and autonomously translocates micron distances without intervention through a forcefield or patterned track. These findings provide the rules for creating cooperative and more sophisticated synthetic molecular motors, thus reducing the gap in capabilities between biological and synthetic motors.