Switching the conformation of a DNA molecule with a chemical oscillator.

pH oscillations generated by a nonequilibrium chemical reaction are used to switch a pH-sensitive DNA structure between two distinct conformations. The utilization of a chemical oscillator represents a novel method for achieving autonomous motion in molecular devices. The oscillatory reaction is a variant of the Landolt reaction and produces pH variations in the range between pH 5 and 7. In this range, a cytosine-rich DNA strand can be switched between a random coil conformation and the folded i-motif structure. The conformational changes are monitored simultaneously with the pH value in fluorescence-resonance energy-transfer experiments.