Divalent metal ions are required for splicing of group I introns, but their role in maintaining
the structure of the active site is still under investigation. Ribonuclease and hydroxyl radical …

The group I intron has served as a model for RNA catalysis since its discovery 25 years ago.
Four recently determined high-resolution crystal structures complement extensive …

Group II introns are mobile genetic elements that have been implicated as agents of genetic
diversity, and serve as important model systems for investigating RNA catalysis and pre …

The upstream site of cleavage of all group I self-splicing introns is identified by an absolutely
conserved U· G base pair. Although a wobble C· A pair can substitute the U· G pair, all other …

Group II introns are self-splicing ribozymes that share a reaction mechanism and a common
ancestor with the eukaryotic spliceosome, thereby providing a model system for …

The splicing process catalyzed by group II intron ribozymes follows the same two-step
pathway as nuclear pre-mRNA splicing. In vivo, the first splicing step of wild-type introns is a …

Group II introns are ribozymes occurring in genes of plants, fungi, lower eukaryotes, and
bacteria. These large RNA molecular machines, ranging in length from 400 to 2500 …

The identical reaction pathway executed by the spliceosome and self-splicing group II intron
ribozymes has prompted the idea that both may be derived from a common molecular …

Group II introns contain a large ribozyme, which catalyzes self-splicing, and the coding
sequence of a reverse transcriptase, the function of which is to cooperate with the ribozyme …

Self-splicing of group I introns requires divalent metal ions to promote catalysis as well as for
the correct folding of the RNA. Lead cleavage has been used to probe the intron RNA for …