title: Self-assembling RNA square.
abstract: The three-dimensional structures of noncoding RNA molecules reveal recurring architectural motifs that have been exploited for the design of artificial RNA nanomaterials. Programmed assembly of RNA nanoobjects from autonomously folding tetraloop-receptor complexes as well as junction motifs has been achieved previously through sequence-directed hybridization of complex sets of long oligonucleotides. Due to size and complexity, structural characterization of artificial RNA nanoobjects has been limited to low-resolution microscopy studies. Here we present the design, construction, and crystal structure determination at 2.2 Å of the smallest yet square-shaped nanoobject made entirely of double-stranded RNA. The RNA square is comprised of 100 residues and self-assembles from four copies each of two oligonucleotides of 10 and 15 bases length. Despite the high symmetry on the level of secondary structure, the three-dimensional architecture of the square is asymmetric, with all four corners adopting distinct folding patterns. We demonstrate the programmed self-assembly of RNA squares from complex mixtures of corner units and establish a concept to exploit the RNA square as a combinatorial nanoscale platform.
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Dibrov
authors.forename: Jaime
authors.initials: J
authors.lastname: McLean
authors.forename: Jerod
authors.initials: J
authors.lastname: Parsons
authors.forename: Thomas
authors.initials: T
authors.lastname: Hermann
mesh_terms: D018360:Crystallography, X-Ray; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry* / Q000235:genetics
chemical_list: D012313:RNA