Center for Biomolecular Structure Lecture Series

The foundational goal of structural DNA nanotechnology is to create rationally designed crystal lattices to precisely organize macromolecules untenable for crystallization to potentially result in the structure of the guest species with X-ray crystallography. DNA is ideal for the construction of three-dimensional crystals due to its distinctive ability to associate via canonical Watson-Crick base pairing which can anneal into a series of "Holliday junctions" that are tailed by complementary "sticky ends" which cohere to form the 3D arrays. Using these features, the structures of only a handful of these DNA scaffolds have been determined. We have recently determined the 2.7 A° structure of a prescribed rhombohedral (R3) lattice containing atomic detail not previously achieved in any other self-assembled DNA crystal system. The role of sticky end sequence was also exhaustively explored to probe its role in crystal order, resulting in a related 2.6 A° scaffold. Additionally, we have undertaken a comprehensive study of the imperative role that sequence plays at each 4-arm junction crossover within the lattice to dictate symmetry and resolution, and to allow for the site-specific placement of guest molecules with atomic precision. These systems provide significant promise towards the construction of improved 3D DNA lattices which could be used as frameworks for immobilizing and solving the structure of molecular guests, templating catalytic materials, and yield significant insight into the mechanism of DNA self-assembly