  Inspired by biology, great progress has been made in creating artificial
molecular motors. However, the dream of harnessing proteins - the building
blocks selected by Nature - to design autonomous motors has so far remained
elusive. Here we report the synthesis and characterization of the Lawnmower, an
autonomous, protein-based artificial molecular motor comprised of a spherical
hub decorated with proteases. Its "burnt-bridge" motion is directed by cleavage
of a peptide lawn, promoting motion towards unvisited substrate. We find that
Lawnmowers exhibit directional motion with average speeds of up to 80 nm/s,
comparable to biological motors. By selectively patterning the peptide lawn on
microfabricated tracks, we furthermore show that the Lawnmower is capable of
track-guided motion. Our work opens an avenue towards nanotechnology
applications of artificial protein motors.
