An efficient thermally induced RNA conformational switch as a framework for the functionalization of RNA nanostructures.

RNA offers a variety of interactions and dynamic conformational switches not available with DNA that may be exploited for the construction of nanomolecular structures. Here, we show how the RNA loop-loop, or "kissing", interaction can be used to construct specific circular RNA arrangements that are capable of thermal isomerization to alternative structures. We also show how this thermally induced structural rearrangement can be used to unmask a functional RNA structure, in this case, a peptide-binding RNA structure, the Rev-response element (RRE) of HIV, thereby acting as a functional peptide-binding switch. The relative ease with which the RRE could be engineered into the RNA substrates suggested that a variety of functional RNA structures may be introduced. In addition, the structural rearrangement was extremely efficient, showing that the "kissing" complexes described in this study may provide a useful framework for the construction of functional RNA-based nanostructures, as well as aid in our understanding of the way RNA functions in biological systems.