title: The solution structure of ribosomal protein L18 from Thermus thermophilus reveals a conserved RNA-binding fold.
abstract: We have determined the solution structure of ribosomal protein L18 from Thermus thermophilus. L18 is a 12.5 kDa protein of the large subunit of the ribosome and binds to both 5 S and 23 S rRNA. In the uncomplexed state L18 folds to a mixed alpha/beta globular structure with a long disordered N-terminal region. We compared our high-resolution structure with RNA-complexed L18 from Haloarcula marismortui and T. thermophilus to examine RNA-induced as well as species-dependent structural differences. We also identified T. thermophilus S11 as a structural homologue and found that the structures of the RNA-recognition sites are conserved. Important features, for instance a bulge in the RNA-contacting beta-sheet, are conserved in both proteins. We suggest that the L18 fold recognizes a specific RNA motif and that the resulting RNA-protein-recognition module is tolerant to variations in sequence.
authors.affiliation: Royal Institute of Technology (KTH), SCFAB, Department of Biotechnology, S-106 91 Stockholm, Sweden.
authors.forename: Esmeralda A
authors.initials: EA
authors.lastname: Woestenenk
authors.forename: George M
authors.initials: GM
authors.lastname: Gongadze
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Shcherbakov
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Rak
authors.forename: Maria B
authors.initials: MB
authors.lastname: Garber
authors.forename: Torleif
authors.initials: T
authors.lastname: Härd
authors.forename: Helena
authors.initials: H
authors.lastname: Berglund
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D019614:Haloarcula marismortui / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012329:RNA, Bacterial / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D016963:Thermus thermophilus / Q000737:chemistry*
chemical_list: D012329:RNA, Bacterial; D012269:Ribosomal Proteins; C029609:ribosomal protein L18