The rational design of nanoscopic DNA tiles has yielded highly ordered crystalline matter in 2D and 3D. The most well‐studied 3D tile is the DNA tensegrity triangle, which is known to self‐assemble into macroscopic crystals. However, contemporary rational design parameters for 3D DNA crystals nearly universally invoke integer numbers of DNA helical turns and Watson–Crick (WC) base pairs. In this study, 24‐bp edges are substituted into a previously 21‐bp (two helical turns of DNA) tensegrity triangle motif to explore whether such unconventional motif can self‐assemble into 3D crystals. The use of noncanonical base pairs in the sticky ends results in a cubic arrangement of tensegrity triangles with exceedingly high symmetry, assembling a lattice from winding helical axes and diamond‐like tessellation patterns. Reverting this motif to sticky ends with Watson–Crick pairs results in a trigonal hexagonal arrangement, replicating this diamond arrangement in a hexagonal context. These results showcase that the authors can generate unexpected, highly complex, pathways for materials design by testing modifications to 3D tiles without prior knowledge of the ensuing symmetry. This study expands the rational design toolbox for DNA nanotechnology; and it further illustrates the existence of yet‐unexplored arrangements of crystalline soft matter.
The successful self‐assembly of tensegrity triangle DNA crystals heralded the ability to programmably construct macroscopic crystalline nanomaterials from rationally‐designed, nanoscale components. This 3D DNA tile owes its “tensegrity” nature to its three rotationally stacked double helices locked together by the tensile winding of a center strand segmented into 7 base pair (bp) inter‐junction regions, corresponding to two‐thirds of a helical turn of DNA. All reported tensegrity triangles to date have employed turn inter‐junction segments, yielding right‐handed, antiparallel, “J1” junctions. Here a minimal DNA triangle motif consisting of 3‐bp inter‐junction segments, or one‐third of a helical turn is reported. It is found that the minimal motif exhibits a reversed morphology with a left‐handed tertiary structure mediated by a locally‐parallel Holliday junction—the “L1” junction. This parallel junction yields a predicted helical groove matching pattern that breaks the pseudosymmetry between tile faces, and the junction morphology further suggests a folding mechanism. A Rule of Thirds by which supramolecular chirality can be programmed through inter‐junction DNA segment length is identified. These results underscore the role that global topological forces play in determining local DNA architecture and ultimately point to an under‐explored class of self‐assembling, chiral nanomaterials for topological processes in biological systems.
more » « less- NSF-PAR ID:
- 10388757
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small
- Volume:
- 19
- Issue:
- 12
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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