A quasi-cyclic RNA nano-scale molecular object constructed using kink turns. Issue 33 (10th August 2016)

• Record Type: Journal Article
• Authors: Huang, Lin; Lilley, David M. J.
• Is Part Of: Nanoscale. Volume 8:Issue 33(2016)
• Page Start: 15189
• Page End: 15195
• Publication Date: 2016-08-10
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c6nr05186c
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : The k-turn is a powerful building block in the construction of nano-scale molecular objects, exemplified by a quasi-circular six-k-turn object. Abstract : k-Turns are widespread RNA architectural elements that mediate tertiary interactions. We describe a double-kink-turn motif comprising two inverted k-turns that forms a tight horse-shoe structure that can assemble into a variety of shapes by coaxial association of helical ends. Using X-ray crystallography we show that these assemble with two (dumbell), three (triangle) and four units (square), with or without bound protein, within the crystal lattice. In addition, exchange of a single basepair can almost double the pore radius or shape of a molecular assembly. On the basis of this analysis we synthesized a 114 nt self-complementary RNA containing six k-turns. The crystal structure of this species shows that it forms a quasi-cyclic triangular object. These are randomly disposed about the three-fold axis in the crystal lattice, generating a circular RNA of quasi D 3 symmetry with a shape reminiscent of that of a cyclohexane molecule in its chair conformation. This work demonstrates that the k-turn is a powerful building block in the construction of nano-scale molecular objects, and illustrates why k-turns are widely used in natural RNA molecules to organize long-range architecture and mediate tertiary contacts.