title: Crystal structure of the spliceosomal 15.5kD protein bound to a U4 snRNA fragment.
abstract: We have determined the crystal structure of a spliceosomal RNP complex comprising the 15.5kD protein of the human U4/U6.U5 tri-snRNP and the 5' stem-loop of U4 snRNA. The protein interacts almost exclusively with a purine-rich (5+2) internal loop within the 5' stem-loop, giving an unusual RNA fold characterized by two tandem sheared G-A base pairs, a high degree of purine stacking, and the accommodation of a single RNA base, rotated out of the RNA chain, in a pocket of the protein. Apart from yielding the structure of an important entity in the pre-mRNA splicing apparatus, this work also implies a model for the complex of the 15.5kD protein with box C/D snoRNAs. It additionally suggests a general recognition principle in a novel family of RNA binding proteins.
authors.affiliation: Institut für Molekularbiologie und Tumorforschung, Philipps-Universität Marburg, Emil-Mannkopff-Strasse 2, 35037 Marburg, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Vidovic
authors.forename: S
authors.initials: S
authors.lastname: Nottrott
authors.forename: K
authors.initials: K
authors.lastname: Hartmuth
authors.forename: R
authors.initials: R
authors.lastname: Lührmann
authors.forename: R
authors.initials: R
authors.lastname: Ficner
mesh_terms: D000595:Amino Acid Sequence; D020029:Base Pairing; D001483:Base Sequence; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D011687:Purines / Q000378:metabolism; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry* / Q000378:metabolism*; D020718:Ribonucleoproteins, Small Nucleolar / Q000737:chemistry; D016415:Sequence Alignment; D017381:Spliceosomes / Q000737:chemistry* / Q000235:genetics
chemical_list: D011687:Purines; D012322:RNA Precursors; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; C405482:U4 small nuclear RNA