title: Structural features that give rise to the unusual stability of RNA hairpins containing GNRA loops.
abstract: The most frequently occurring RNA hairpins in 16S and 23S ribosomal RNA contain a tetranucleotide loop that has a GNRA consensus sequence. The solution structures of the GCAA and GAAA hairpins have been determined by nuclear magnetic resonance spectroscopy. Both loops contain an unusual G-A base pair between the first and last residue in the loop, a hydrogen bond between a G base and a phosphate, extensive base stacking, and a hydrogen bond between a sugar 2'-end OH and a base. These interactions explain the high stability of these hairpins and the sequence requirements for the variant and invariant nucleotides in the GNRA tetranucleotide loop family.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.
authors.forename: H A
authors.initials: HA
authors.lastname: Heus
authors.forename: A
authors.initials: A
authors.lastname: Pardi
mesh_terms: D001483:Base Sequence; D003196:Computer Graphics; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009843:Oligoribonucleotides / Q000737:chemistry; D012313:RNA / Q000737:chemistry / Q000648:ultrastructure*; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D009843:Oligoribonucleotides; D012313:RNA