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Science 3 April 2009:
Vol. 324. no. 5923, pp. 67 - 71
DOI: 10.1126/science.1170336
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Reports

A Bipedal DNA Brownian Motor with Coordinated Legs

Tosan Omabegho,1 Ruojie Sha,2 Nadrian C. Seeman2*

A substantial challenge in engineering molecular motors is designing mechanisms to coordinate the motion between multiple domains of the motor so as to bias random thermal motion. For bipedal motors, this challenge takes the form of coordinating the movement of the biped's legs so that they can move in a synchronized fashion. To address this problem, we have constructed an autonomous DNA bipedal walker that coordinates the action of its two legs by cyclically catalyzing the hybridization of metastable DNA fuel strands. This process leads to a chemically ratcheted walk along a directionally polar DNA track. By covalently cross-linking aliquots of the walker to its track in successive walking states, we demonstrate that this Brownian motor can complete a full walking cycle on a track whose length could be extended for longer walks. We believe that this study helps to uncover principles behind the design of unidirectional devices that can function without intervention. This device should be able to fulfill roles that entail the performance of useful mechanical work on the nanometer scale.

1 School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
2 Department of Chemistry, New York University, New York, NY 10003, USA.

* To whom correspondence should be addressed. E-mail: ned.seeman{at}nyu.edu

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Science. ISSN 0036-8075 (print), 1095-9203 (online)