title: Group II intron lariat: Structural insights into the spliceosome.
abstract: Group II introns are self-splicing catalytic RNAs found in bacteria and the organelles of fungi and plants. They are thought to share a common ancestor with the spliceosome, which catalyzes the removal of nuclear introns from pre-mRNAs in eukaryotes. Recent structural and biochemical evidence supports the hypothesis that the spliceosome has a catalytic RNA core homologous to that found in group II introns. The crystal structure of a eukaryotic group IIB intron was recently determined and reveals the architecture of a branched lariat RNA that is also formed by the spliceosome. Here we describe the active site components of this intron and propose a model for RNA splicing involving dynamic base triples in the catalytic triad. Based on this structure, we draw analogies to the U2/U6 snRNA pairing and RNA-protein interactions that form in the active site of the spliceosome.
authors.affiliation: a Department of Chemistry and Biochemistry ; University of California, San Diego ; La Jolla , CA USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Peters
authors.affiliation: a Department of Chemistry and Biochemistry ; University of California, San Diego ; La Jolla , CA USA.
authors.forename: Navtej
authors.initials: N
authors.lastname: Toor
mesh_terms: D020029:Base Pairing; D020134:Catalytic Domain; D007438:Introns / Q000235:genetics*; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D022821:RNA Splice Sites; D012326:RNA Splicing / Q000502:physiology; D017381:Spliceosomes / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D022821:RNA Splice Sites
keywords: RNA splicing; branch point; group II intron; lariat; spliceosome