title: Involvement of a GNRA tetraloop in long-range RNA tertiary interactions.
abstract: Terminal loops with a GNRA consensus sequence are widespread in RNA. It has been suggested that these loops act as "anchors" during tertiary folding, by interacting in a sequence-specific way with helices at distant locations along the molecule. We now show that a GUGA loop changes state upon disruption of the tertiary architecture of a self-splicing group I intron. Successful replacement of the postulated loop-helix contact by classical base-pairing points to binding of the loop into the shallow (minor) groove of the helix, as also indicated by partial restoration of ribozyme stability upon a specific double nucleotide substitution.
authors.affiliation: Centre de Génétique Moléculaire du C.N.R.S., Gif-sur-Yvette, France.
authors.forename: L
authors.initials: L
authors.lastname: Jaeger
authors.forename: F
authors.initials: F
authors.lastname: Michel
authors.forename: E
authors.initials: E
authors.lastname: Westhof
mesh_terms: D017122:Bacteriophage T4; D001483:Base Sequence; D006860:Hydrogen Bonding; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*; D012367:RNA, Viral / Q000737:chemistry
chemical_list: D012367:RNA, Viral; D012313:RNA