A minor groove RNA triple helix within the catalytic core of a group I intron.
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.
Szewczak
A A
AA
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
Ortoleva-Donnelly
L
L
Ryder
S P
SP
Moncoeur
E
E
Strobel
S A
SA
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*
D016337:RNA, Catalytic; D016053:RNA, Protozoan