title: Structure of 2',5'-linked tetraribonucleotide loops: a novel RNA motif.
abstract: We report on the three dimensional structure of an RNA hairpin containing a 2',5'-linked tetraribonucleotide loop, namely, 5'-rGGAC(UUCG)GUCC-3' (where UUCG = U(2'p5')U(2'p5')C(2'p5')G(2'p5')). We show that the 2',5'-linked RNA loop adopts a conformation that is quite different from that previously observed for the native 3',5'-linked RNA loop. The 2',5'-RNA loop is stabilized by (a) U:G wobble base pairing, with both bases in the anti conformation, (b) extensive base stacking, and (c) sugar-base contacts, all of which contribute to the extra stability of this hairpin structure.
authors.affiliation: Department of Chemistry, McGill University, Montreal, Quebec, Canada.
authors.forename: Rami N
authors.initials: RN
authors.lastname: Hannoush
authors.forename: Alexei Yu
authors.initials: AY
authors.lastname: Denisov
authors.forename: Kalle
authors.initials: K
authors.lastname: Gehring
authors.forename: Masad J
authors.initials: MJ
authors.lastname: Damha
mesh_terms: D001483:Base Sequence; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009843:Oligoribonucleotides / Q000138:chemical synthesis*; D012313:RNA / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009843:Oligoribonucleotides; D012313:RNA