Cells employ molecular motors to transport cargo, copy genetic information, and cooperatively produce large scale mechanical forces and structural asymmetries. A rapidly developing technological goal is the ability to perform analogous functions outside of cellular contexts, by integrating engineered molecular motors into microscale devices that are able to perform diagnostic functions. Prototypical devices have been constructed that employ biologically derived motors such as kinesins, but much remains to be understood about how to engineer the molecular motors themselves. This proposal combines DNA nanotechnology, protein engineering, and single-molecule measurements of nanoscale motion to advance the field of molecular motor engineering. In the first aim, powerful single-molecule methods, originally developed for the study of biological molecular motors, will be used to characterize the kinetics and force producing abilities of a DNA motor that mimics striding motors such as kinesin and myosin. The motor is rudimentary, but it is among the first rationally designed molecular machines to display directed motion. This work should provide some of the first detailed kinetic data on a synthetic molecular motor. In the second aim, dynamic DNA devices will be integrated into the ATP-driven protein motor myosin, to create hybrid nanodevices that can be controlled by DNA signals. These hybrids will have the ability to switch directions, make branch-point turns, and take programmed step sizes. The goal is to create hybrid motors that have novel functionalities which are not found in nature, and eventually to create populations of individually addressable motors working in parallel on complex nanoscale tasks such as shuttling molecules in medical diagnostic devices.
The ability to control motion at the nanoscale with the same capacity as biological molecular motors and machines, but outside of a cell, is a long-term goal of scientists and engineers. We will advance efforts towards this goal by: (1) fully characterizing, at the level of a single molecule, the movements of one of the first synthetic molecular motors capable of directed motion;and (2) by building programmable hybrid motors that contain both synthetic and biological components. Together, these two efforts will aid in the eventual development of sub-millimeter medical diagnostic devices that use molecular motors to shuttle for analysis with unprecedented control.