title: The RNA binding domain of ribosomal protein L11: three-dimensional structure of the RNA-bound form of the protein and its interaction with 23 S rRNA.
abstract: The three-dimensional solution structure has been determined by NMR spectroscopy of the 75 residue C-terminal domain of ribosomal protein L11 (L11-C76) in its RNA-bound state. L11-C76 recognizes and binds tightly to a highly conserved 58 nucleotide domain of 23 S ribosomal RNA, whose secondary structure consists of three helical stems and a central junction loop. The NMR data reveal that the conserved structural core of the protein, which consists of a bundle of three alpha-helices and a two-stranded parallel beta-sheet four residues in length, is nearly the same as the solution structure determined for the non-liganded form of the protein. There are however, substantial chemical shift perturbations which accompany RNA binding, the largest of which map onto an extended loop which bridges the C-terminal end of alpha-helix 1 and the first strand of parallel beta-sheet. Substantial shift perturbations are also observed in the N-terminal end of alpha-helix 1, the intervening loop that bridges helices 2 and 3, and alpha-helix 3. The four contact regions identified by the shift perturbation data also displayed protein-RNA NOEs, as identified by isotope-filtered three-dimensional NOE spectroscopy. The shift perturbation and NOE data not only implicate helix 3 as playing an important role in RNA binding, but also indicate that regions flanking helix 3 are involved as well. Loop 1 is of particular interest as it was found to be flexible and disordered for L11-C76 free in solution, but not in the RNA-bound form of the protein, where it appears rigid and adopts a specific conformation as a result of its direct contact to RNA.
authors.affiliation: National Institute of Dental Research, Bethesda, MD 20892-4326, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Hinck
authors.forename: M A
authors.initials: MA
authors.lastname: Markus
authors.forename: S
authors.initials: S
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Grzesiek
authors.forename: I
authors.initials: I
authors.lastname: Kustonovich
authors.forename: D E
authors.initials: DE
authors.lastname: Draper
authors.forename: D A
authors.initials: DA
authors.lastname: Torchia
mesh_terms: D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism*; D012338:RNA, Ribosomal, 23S / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry*; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism*; D012996:Solutions
chemical_list: D012338:RNA, Ribosomal, 23S; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D012996:Solutions; C027624:ribosomal protein L11; D012313:RNA