title: Structural insights into group II intron catalysis and branch-site selection.
abstract: Group II self-splicing introns catalyze autoexcision from precursor RNA transcripts by a mechanism strikingly similar to that of the spliceosome, an RNA-protein assembly responsible for splicing together the protein-coding parts of most eukaryotic pre-mRNAs. Splicing in both cases initiates via nucleophilic attack at the 5' splice site by the 2' OH of a conserved intron adenosine residue, creating a branched (lariat) intermediate. Here, we describe the crystal structure at 3.0 A resolution of a 70-nucleotide RNA containing the catalytically essential domains 5 and 6 of the yeast ai5gamma group II self-splicing intron, revealing an unexpected two-nucleotide bulged structure around the branch-point adenosine in domain 6.
authors.affiliation: Department of Molecular Biophysics and Biochemistry and, Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Doudna
mesh_terms: D000241:Adenosine / Q000737:chemistry / Q000378:metabolism; D020029:Base Pairing; D001665:Binding Sites; D003028:CME-Carbodiimide / Q000031:analogs & derivatives*; D002384:Catalysis; D003035:Cobalt / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D007438:Introns; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism; D012326:RNA Splicing; D012331:RNA, Fungal / Q000737:chemistry* / Q000378:metabolism
chemical_list: D012322:RNA Precursors; D012331:RNA, Fungal; C030862:cobalt ammonium complex; C060331:1-cyclohexyl-3-(2-(4-morpholinyl)ethyl)carbodiimide; D003028:CME-Carbodiimide; D003035:Cobalt; D008345:Manganese; D008274:Magnesium; D000241:Adenosine