Reciprocal DNA nanomechanical devices controlled by the same set strands.

Reciprocating devices are key features in macroscopic machines. We have adapted the DNA PX-JX(2) device to a reciprocal format. The PX-JX(2) device is a robust sequence-dependent nanomachine, whose state is established by a pair of control strands that set it to be either in the PX state or in the JX(2) state. The two states differ by a half-turn rotation between their ends. Here we report the construction of a pair of reciprocal PX-JX(2) devices, wherein the control strands leading to the PX state in one device lead to the JX(2) state in the other device and vice versa. The formation, transformation, and reciprocal motions of these two device systems are confirmed using gel electrophoresis and atomic force microscopy. This system is likely to be of use for molecular robotic applications where reciprocal motions are of value in addition its inherent contribution to molecular choreography and molecular aesthetics.