Molecular Motor-Powered Nanodevices: Mechanisms for Control
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Although the biophysical and biochemical properties of motor proteins have been well studied, only recently have attempts been made to develop them as mechanical components in hybrid nanoengineered systems. The motor protein F1-ATPase is the smallest rotary motor known and can generate forces compatible with currently producible nanomechanical structures; we have previously fabricated and operated hybrid organic–inorganic nanodevices powered by F1-ATPase. Control of device activity is a critical aspect in the engineering and deployment of integrated nanomachines. There are a variety of possible control mechanisms, including mechanical, optical, electrical, and chemical. We have previously implemented chemical controls into F1-ATPase. These controls followed from the design and construction of allosteric metal-binding sites that constituted a reversible and repeatable on/off switch of motor activity which was demonstrated in the bulk and at the single molecule level. For biomolecular motor-powered hybrid devices to fully realize their potential, progressing beyond scientific experiments and low-functioning curiosities, the devices and device components should be entirely reimagined from an engineering perspective. Development of a library of controls acting directly on motor proteins, their fuel, the components interfaced with them, or a combination of all of these will be highly useful toward increasing the utility, applicability, and range of operation of engineered biomotors.
In this article, we will address these issues, describing the results of current research in which control of mechanical proteins incorporated into hybrid devices has been addressed for the first time. We will also discuss our recent work in which chemical controls were incorporated into the F1-ATPase, able to reversibly start and stop the mechanical motion at the single molecule level. We will conclude with an outlook of the field as a whole and future directions.