title: A minor groove RNA triple helix within the catalytic core of a group I intron.
abstract: Close packing of several double helical and single stranded RNA elements is required for the Tetrahymena group I ribozyme to achieve catalysis. The chemical basis of these packing interactions is largely unknown. Using nucleotide analog interference suppression (NAIS), we demonstrate that the P1 substrate helix and J8/7 single stranded segment form an extended minor groove triple helix within the catalytic core of the ribozyme. Because each triple in the complex is mediated by at least one 2'-OH group, this substrate recognition triplex is unique to RNA and is fundamentally different from major groove homopurine-homopyrimidine triplexes. We have incorporated these biochemical data into a structural model of the ribozyme core that explains how the J8/7 strand organizes several helices within this complex RNA tertiary structure.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Szewczak
authors.forename: L
authors.initials: L
authors.lastname: Ortoleva-Donnelly
authors.forename: S P
authors.initials: SP
authors.lastname: Ryder
authors.forename: E
authors.initials: E
authors.lastname: Moncoeur
authors.forename: S A
authors.initials: SA
authors.lastname: Strobel
mesh_terms: D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics*; D007438:Introns; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000235:genetics; D016053:RNA, Protozoan / Q000737:chemistry*; D013768:Tetrahymena / Q000235:genetics*
chemical_list: D016337:RNA, Catalytic; D016053:RNA, Protozoan