Stereochemical course of catalysis by the Tetrahymena ribozyme

Science  12 May 1989:
Vol. 244, Issue 4905, pp. 692-694
DOI: 10.1126/science.2470151


The group I intron from Tetrahymena catalyzes phosphodiester transfer reactions on various RNA substrates. A modified RNA substrate with a phosphorothioate group in one stereoisomeric form at the site of reaction was synthesized in order to determine the stereochemical course of an RNA-catalyzed reaction. The reaction product was digested with a stereospecific nuclease to determine the configuration of the product phosphorothioate. The reaction occurs with inversion of configuration at phosphorus, implying an in-line pathway for the reaction.