Three critical hydrogen bonds determine the catalytic activity of the Diels-Alderase ribozyme.

ABSTRACT: Compared to protein enzymes, our knowledge about how RNA accelerates chemical reactions is rather limited. The crystal structures of a ribozyme that catalyzes Diels-Alder reactions suggest a rich tertiary architecture responsible for catalysis. In this study, we systematically probe the relevance of crystallographically observed ground-state interactions for catalytic function using atomic mutagenesis in combination with various analytical techniques. The largest energetic contribution apparently arises from the precise shape complementarity between transition state and catalytic pocket: A single point mutant that folds correctly into the tertiary structure but lacks one H-bond that normally stabilizes the pocket is completely inactive. In the rate-limiting chemical step, the dienophile is

SUBMITTER: Kraut S 

PROVIDER: S-EPMC3273808 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature