posted on 2021-10-05, 15:15authored byBrandon Lu, Simon Vecchioni, Yoel P. Ohayon, Ruojie Sha, Karol Woloszyn, Bena Yang, Chengde Mao, Nadrian C. Seeman
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 Å3far
larger than the rhombohedral counterpart (5 nm, 330 000 Å3).