Programmed catalysis within stimuli-responsive mechanically unlocked nanocavities in DNA origami tiles

Abstract

The assembly of reversible stimuli-responsive locked DNA origami tiles being unlocked, in the presence of appropriate triggers, to form nanocavities in the origami rafts, is introduced. In the presence of ATP, K+-ion-stabilized G-quadruplexes or pH-responsive T-A·T triggers and appropriately engineered "helper units", the origami rafts are unlocked to form nanocavities. By the application of appropriate counter-triggers, the nanocavities are relocked, thus establishing the switchable and reversible "mechanical"opening and closure mechanism of the nanocavities. The interconnection of the stimuli-responsive origami tiles into dimer structures enables the programmed triggered unlocking of each of the origami tiles, or both of the origami tiles, to yield dictated nanocavity-containing tiles. In addition, the functionalization of the opposite faces of the origami tiles with Mg2+-ion-dependent DNAzyme subunits leads, upon the triggered unlocking of the nanocavities, to the self-assembly of the active DNAzymes in the confined cavities. By the cyclic opening and closure of the cavities the reversible "ON"/"OFF"activation of the Mg2+-ion-dependent DNAzyme is demonstrated. Furthermore, upon the tethering of different Mg2+-ion-dependent subunits to the opposite faces of stimuli-responsive dimer origami tiles, the triggered programmed catalytic operation of different Mg2+-ion-dependent DNAzymes in the confined nanocavities, associated with the origami tiles, is demonstrated.