Single-pair FRET characterization of DNA tweezers

The self-assembly properties of DNA make it an ideal choice for the construction of nanomachines such as DNA tweezers. Because nanomachines function as individual units, they need to be studied on the single-molecule level. From single-pair FRET investigations, we show that open tweezers exist in a single conformation with minimal FRET efficiency, whereas upon addition of a closing strand, three conformations are observed, which are averaged out in ensemble measurements.