Stimuli-responsive and reversible nanoassemblies of G-triplex.

G-triplex (G3) structures formed with three consecutive G-tracts have recently been identified as newly emerged guanine-rich DNA foldings. It likely implicates wide biological functions of G3s as occurring to the G-quadruplex (G4) structures formed with four consecutive G-tracts. However, in comparison to fruitful reports on the G4 nanoassemblies that organize monomers together in a controllable manner, the G3-favored nanoassemblies have yet to be explored. In this work, we found that a natural alkaloid of sanguinarine can serve as a dynamic ligand glue to reversibly switch the dimeric nanoassemblies of the thrombin binding aptamer G3 (TBA-G3). The glue planarity was considered to be a crucial factor to realize this switching. More importantly, external stimuli including pH, sulfite, O 2 and H 2 O 2 can be employed as common regulators to easily modulate the glue's adhesivity for constructing and destructing the G3 nanoassemblies as a result of ligand converting between featured isoforms. However, this assembly behavior does not occur to the counterpart TBA-G4. Our work first demonstrates the higher-order G3 nanoassemblies that can be reversibly operated by manipulating ligands' adhesivity. This provides an alternative way to understand the unique behavior of guanine-rich sequences and cause more attention to the G3 foldings since the nanoassembly event investigated herein maybe occurs in living cells.