title: Structure and functional implications of a complex containing a segment of U6 RNA bound by a domain of Prp24.
abstract: U6 RNA plays a critical role in pre-mRNA splicing. Assembly of U6 into the spliceosome requires a significant structural rearrangement and base-pairing with U4 RNA. In the yeast Saccharomyces cerevisiae, this process requires the essential splicing factor Prp24. We present the characterization and structure of a complex containing one of Prp24's four RNA recognition motif (RRM) domains, RRM2, and a fragment of U6 RNA. NMR methods were used to identify the preferred U6 binding sequence of RRM2 (5'-GAGA-3'), measure the affinity of the interaction, and solve the structure of RRM2 bound to the hexaribonucleotide AGAGAU. Interdomain contacts observed between RRM2 and RRM3 in a crystal structure of the free protein are not detectable in solution. A structural model of RRM1 and RRM2 bound to a longer segment of U6 RNA is presented, and a partial mechanism for Prp24's annealing activity is proposed.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Martin-Tumasz
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Reiter
authors.forename: David A
authors.initials: DA
authors.lastname: Brow
authors.forename: Samuel E
authors.initials: SE
authors.lastname: Butcher
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D004265:DNA Helicases / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000737:chemistry* / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry* / Q000378:metabolism; D012262:Ribonucleoside Diphosphate Reductase / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: C401305:Prp24 protein, S cerevisiae; D012331:RNA, Fungal; D012342:RNA, Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; C405486:U6 small nuclear RNA; D012262:Ribonucleoside Diphosphate Reductase; C459081:Rrm3 protein, S cerevisiae; D004265:DNA Helicases