An electrochemically reversible DNA switch

We have developed a novel strategy for regulating G-quadruplex formation of a DNA sequence that relies on electrochemical reduction of Pb²⁺ and oxidation of Pb. The DNA aptamer sequence (PW17) forms a G-quadruplex structure through interaction with Pb²⁺. The electrochemical reduction of Pb²⁺ to Pb, which accumulates on the electrode surface, brings about destruction of the G-quadruplex structure. Subsequently by applying oxidation voltage, Pb on the electrode surface goes back to Pb²⁺ and released Pb²⁺ binds again to the non-structured free PW17 sequence resulting in reformation of the G-quadruplex structure. In this manner, a PW17 DNA sequence can be reversibly switched between a very stable G-quadruplex state and a non-structured state. The results should provide insight into the development of novel mechanical DNA nanomachines that are driven by simple electrochemical processes.