Figure 1: Schematic for the synthesis and programmable assembly of dsDNA [3]pseudocatenane.
From: Interlocked DNA nanostructures controlled by a reversible logic circuit
(a) The synthesized [3]pseudocatenane contains C-rich (cyan, C6TC6) and G-rich (purple, G3ACG3) branches. The rings L-M and M-R are held together by hybridization in short sections, to form the interlocked structure. (b) Addition of RO-L and RO-R (that is, ROs) triggers a structural conversion from [3]pseudocatenane to [3]catenane, where RO-L and RO-R (underlined: the active sequences) are hybridized with two gaps of ring M to displace L and R thereby allowing them to move freely. A bimolecular i-motif (cyan) can then form in the presence of H+, resulting in head-motif cyclization in the interlocked system.
