Two major tertiary folding transitions of the Tetrahymena catalytic RNA

摘要: The L-21 Tetrahymena ribozyme, an RNA molecule with sequence-specific endoribonuclease activity derived from a self-splicing group I intron, provides model system for studying the folding problem. A 160 nucleotide, independently domain of tertiary structure (the P4-P6 domain) comprises about half ribozyme. We now apply Fe(II)-EDTA cleavage to mutants ribozyme explore role individual structural elements in at equilibrium. Deletion peripheral near 3' end destabilizes region catalytic core (P3-P7) without altering domain. Three different mutations within that destabilize its also shift P3-P7 higher MgCl2 concentrations. conclude extended and 3'-terminal is least part stabilize core. organization into domains may be common large RNAs, including ribosomal RNAs. Furthermore, observation domain-domain interactions supports feasibility primitive spliceosome any proteins.