Manipulating the Assembly of DNA Nanostructures and Their Enzymatic Properties by Incorporating a 5'-5' Polarity of Inversion Site in the G-Tract.

Supramolecular DNA complexes consisting of both DNA duplexes and tetrameric G-quadruplexes are fabricated successfully by utilizing a single short DNA strand that contains one 5'-5' polarity of inversion site in the middle of G-tract. The resulting DNA supramolecules exhibit significantly high peroxidase activities after interaction with hemin due to the presence of various G-quadruplex-duplex (G4-duplex) interfaces. Significantly, we find that the addition of a C-rich fragment to the designed sequence not only allows the self-assembly of two-dimensional porous DNA nanostructures via the formation of dimeric i-motif structures but also could act as a control element to facilitate the generation of pH-sensitive G4-based DNAzymes. The enhanced catalytic activity obtained from specific sequence modifications as well as the controllable feature of these DNA nanostructures can significantly benefit further applications of DNA functional materials in complex biological systems.