No abstract

The future of RNA origami writ large Researchers have long fabricated intricate nanostructures from carefully linked DNA strands. Now they can use RNA made by gene expression, which avoids the costly strand synthesis and lengthy annealing steps necessary with DNA origami. Geary et al. used molecular modeling to extend the size of folded RNA origami structures (see the Perspective by Leontis and Westhof). The modeling revealed assembly patterns for linking single-stranded RNA into A-form helices. The authors created two-dimensional structures as large as 660 nucleotides on mica surfaces. Science , this issue p. 799 ; see also p. 732

The DNA origami method allows the folding of long, single-stranded DNA sequences into arbitrary two-dimensional structures by a set of designed oligonucleotides. The method has revealed an unexpected strength and efficiency for programmed self-assembly of molecular nanostructures and makes it possible to produce fully addressable nanostructures with wide-reaching application potential within the emerging area of nanoscience. Here we present a user-friendly software package for designing DNA origami structures ( http://www.cdna.dk/origami ) and demonstrate its use by the design of a dolphin-like DNA origami structure that was imaged by high-resolution AFM in liquid. The software package provides automatic generation of DNA origami structures, manual editing, interactive overviews, atomic models, tracks the design history, and has a fully extendable toolbox. From the AFM images, it was demonstrated that different designs of the dolphin tail region provided various levels of flexibility in a predictable fashion. Finally, we show that the addition of specific attachment sites promotes dimerization between two independently self-assembled dolphin structures, and that these interactions stabilize the flexible tail.