title: Structure of 23S rRNA hairpin 35 and its interaction with the tylosin-resistance methyltransferase RlmAII.
abstract: The bacterial rRNA methyltransferase RlmAII (formerly TlrB) contributes to resistance against tylosin-like 16-membered ring macrolide antibiotics. RlmAII was originally discovered in the tylosin-producer Streptomyces fradiae, and members of this subclass of methyltransferases have subsequently been found in other Gram-positive bacteria, including Streptococcus pneumoniae. In all cases, RlmAII methylates 23S rRNA at nucleotide G748, which is situated in a stem-loop (hairpin 35) at the macrolide binding site of the ribosome. The conformation of hairpin 35 recognized by RlmAII is shown here by NMR spectroscopy to resemble the anticodon loop of tRNA. The loop folds independently of the rest of the 23S rRNA, and is stabilized by a non-canonical G-A pair and a U-turn motif, rendering G748 accessible. Binding of S.pneumoniae RlmAII induces changes in NMR signals at specific nucleotides that are involved in the methyltransferase-RNA interaction. The conformation of hairpin 35 that interacts with RlmAII is radically different from the structure this hairpin adopts within the 50S subunit. This indicates that the hairpin undergoes major structural rearrangement upon interaction with ribosomal proteins during 50S assembly.
authors.affiliation: Laboratoire de RMN, ICSN-CNRS, 1 ave de la terrasse, 91190 Gif-sur-Yvette, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lebars
authors.forename: Satoko
authors.initials: S
authors.lastname: Yoshizawa
authors.forename: Anne R
authors.initials: AR
authors.lastname: Stenholm
authors.forename: Eric
authors.initials: E
authors.lastname: Guittet
authors.forename: Stephen
authors.initials: S
authors.lastname: Douthwaite
authors.forename: Dominique
authors.initials: D
authors.lastname: Fourmy
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology; D000926:Anticodon; D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D024881:Drug Resistance, Bacterial; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012338:RNA, Ribosomal, 23S / Q000737:chemistry* / Q000378:metabolism*; D015645:Tylosin / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000926:Anticodon; D001426:Bacterial Proteins; D012338:RNA, Ribosomal, 23S; D008780:Methyltransferases; C119401:TlrB protein, Streptomyces fradiae; D015645:Tylosin