Crystal structure of a continuous three-dimensional DNA lattice

DNA has proved to be a versatile material for the rational design and assembly of nanometer scale objects. Here we report the crystal structure of a continuous three-dimensional DNA lattice formed by the self-assembly of a DNA 13-mer. The structure consists of stacked layers of parallel helices with adjacent layers linked through parallel-stranded base pairing. The hexagonal lattice geometry contains solvent channels that appear large enough to allow X-linked guest molecules into the crystal. We have successfully used these parallel base pairs to design and produce crystals with greatly enlarged solvent channels. This lattice may have applications as a molecular scaffold for structure determination of guest molecules, as a molecular sieve, or in the assembly of molecular electronics. Predictable non-Watson-Crick base pairs, like those described here, may present a new tool in structural DNA nanotechnology.