Controlling kinesin motor proteins in nanoengineered systems through a metal‐binding on/off switch

A significant challenge in utilizing kinesin biomolecular motors in integrated nanoscale systems is the ability to regulate motor function in vitro. Here we report a versatile mechanism for reversibly controlling the function of kinesin biomolecular motors independent of the fuel supply (ATP). Our approach relied on inhibiting conformational changes in the neck‐linker region of kinesin, a process necessary for microtubule transport. We introduced a chemical switch into the neck‐linker of kinesin by genetically engineering three histidine residues to create a Zn 2+ ‐binding site. Gliding motility of microtubules by the mutant kinesin was successfully inhibited by ≥10 µM Zn 2+ , as well as other divalent metals. Motility was successfully restored by removal of Zn 2+ using a number of different chelators. Lastly, we demonstrated the robust and cyclic nature of the switch using sequential Zn 2+ /chelator additions. Overall, this approach to controlling motor function is highly advantageous as it enables control of individual classes of biomolecular motors while maintaining a consistent level of fuel for all motors in a given system or device. Biotechnol. Bioeng. 2008;101: 478–486. © 2008 Wiley Periodicals, Inc.