title: The structure and folding of kink turns in RNA.
abstract: The kink turn (k-turn) is a widespread structural motif that introduces a tight kink into the axis of double-stranded RNA, with an included angle ∼60°. A standard k-turn comprises a three-nucleotide bulge followed on the 3' side by a G•A pair, an A•G pair, and usually further non-Watson-Crick pairs. The kinked conformation may be stabilized by three processes. These are the addition of metal ions, the binding of proteins such as the L7Ae family, and by the formation of tertiary interactions. The structure is characterized by specific A-minor interactions with the adenine nucleobases of the G•A pairs, and some very well-conserved hydrogen bonds involving 2'-hydroxyl groups. We can identify two classes of k-turns, that differ in the manner of the hydrogen bonding at the adenine of the bulge-distal G•A pair.
authors.affiliation: Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dundee, UK. d.m.j.lilley@dundee.ac.uk
authors.forename: David M J
authors.initials: DM
authors.lastname: Lilley
mesh_terms: D000818:Animals; D001665:Binding Sites; D006801:Humans; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008670:Metals / Q000737:chemistry; D009690:Nucleic Acid Conformation; D059372:Nucleotide Motifs; D011485:Protein Binding; D012313:RNA / Q000737:chemistry*; D059370:RNA Folding; D012330:RNA, Double-Stranded / Q000737:chemistry; D016601:RNA-Binding Proteins / Q000378:metabolism
chemical_list: D007477:Ions; D008670:Metals; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D012313:RNA