From molecular to macroscopic via the rational design of a self-assembled 3D DNA crystal

Creating a macroscopic object, such as a crystal, with the microscopic molecular structure desired is a challenge. One promising approach is the use of macromolecules with robust three-dimensional motifs and sticky ends so that, by attaching to one another, they can form a periodic arrangement that can be investigated by crystallographic techniques. Zheng et al. use DNA for this purpose, arranged in a structural motif called a tensegrity triangle, and can grow crystals of the order of 200 micrometres in size, in which the positions of the atoms can be determined with a precision of 4 Å. The highly specific interaction between complementary DNA strands makes it possible to realize the desired and designed structure for the unit cell of the crystal. The latter also exhibits periodic holes, which could potentially be used to host biomolecules in a three-dimensional periodic arrangement, making it possible to determine their structure even if they do not crystallize on their own.