Chirality is an essential aspect in nature. [1] Most biomolecules, such as amino acids, sugars, RNA, DNA, and proteins, are chiral, as are the large entities assembled from these molecules. The ability of enzymes and cell receptors to readily distinguish different stereoisomers (enantiomers) of chiral substrates leads to highly efficient and stereoselective reactions and binding. An understanding of and ability to control chirality is of crucial importance for organic synthesis, [2] molecular separation, [3] guest encapsulation, [4] drug design, [5] and other endeavors. In recent years, the exploration of biomimetic supramolecular self-assembly has provided a means to study the formation of chiral objects. This approach suggests a way to understand and control chirality at the molecular level. Previous studies mostly focused on the asymmetric assembly of nonbiological organic molecules through noncovalent interactions, [6][7][8] such as hydrogen bonds, metal coordination, or p-p interactions. Herein, we report a well-defined chiral nanooctahedron structure which is exclusively composed of DNA molecules. The construction of the DNA octahedron involves a rather simple one-pot process involving only three unique synthetic DNA single strands. Cryogenic electron microscopy (cryoEM) revealed a three-dimensional (3D) structural map with a resolution of 12 , from which the chiral features of the DNA octahedron could be identified clearly.
DNA is a superb nanoscale building material owing to its excellent molecular-recognition capability and well-defined double-helical structure. [9] A variety of DNA nanostructures [10][11][12][13] have been engineered from synthetic DNA molecules. Since natural B-form DNA adopts a stereoisomerically pure right-handed double-helical structure, large DNA nanostructures can presumably also adopt chiral conformations. However, the chirality of DNA assemblies at the nanoscale