title: Adenine-guanine base pairing ribosomal RNA.
abstract: Analyses of secondary structures proposed for ribosomal RNA's show that, of the different kinds of base pairs directly adjoining the ends of postulated double-helical regions, only A-G with A at the 5' end significantly exceeds the number expected for a random base distribution. An A(syn)-G(trans) hydrogen-bonded basepair is proposed. This could fit at the end of an undistorted double helix, but would prevent further base stacking, thus favoring a break in the double helix to produce a non-linear tertiary structure.
mesh_terms: D000225:Adenine; D001482:Base Composition; D001483:Base Sequence; D004926:Escherichia coli / Q000032:analysis; D006147:Guanine; D006860:Hydrogen Bonding; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal
chemical_list: D012335:RNA, Ribosomal; D006147:Guanine; D000225:Adenine