3D Hexagonal Arrangement of DNA Tensegrity Triangles
Brandon Lu, Simon Vecchioni, Yoel P. Ohayon, Ruojie Sha, Karol Woloszyn, Bena Yang, Chengde Mao, Nadrian C. Seeman
Abstract
The tensegrity triangle motif utilizes Watson–Crick sticky end cohesion to self-assemble into a rhombohedral crystal lattice using complementary 5′-GA and 5′-TC sticky ends. Here, we report that using noncanonical 5′-AG and 5′-TC sticky ends in otherwise isomorphic tensegrity triangles results in crystal self-assembly in the P63 hexagonal space group as revealed by X-ray crystallography. In this structure, the DNA double helices bend at the crossover positions, a feature that was not observed in the original design. Instead of propagating linearly, the tilt between base pairs of each right-handed helix results in a left-handed superstructure along the screw axis, forming a microtubule-like structure composed of three double helices with an unbroken channel at the center. This hexagonal lattice has a cavity diameter of 11 nm and a unit cell volume of 886 000 Å3—far larger than the rhombohedral counterpart (5 nm, 330 000 Å3).