3D Hexagonal Arrangement of DNA Tensegrity Triangles

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 P6(3) 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 A(3)-far larger than the rhombohedral counterpart 5 nm, 330 000 A(3)).

Automated summary

It has been discovered that using noncanonical sticky ends in tensegrity triangle crystal structures can alter the self-assembly process, resulting in a left-handed superstructure and microtubule-like structure formation.