NMR structure of the active conformation of the Varkud satellite ribozyme cleavage site.

ABSTRACT: Substrate cleavage by the Neurospora Varkud satellite (VS) ribozyme involves a structural change in the stem-loop I substrate from an inactive to an active conformation. We have determined the NMR solution structure of a mutant stem-loop I that mimics the active conformation of the cleavage site internal loop. This structure shares many similarities, but also significant differences, with the previously determined structures of the inactive internal loop. The active internal loop displays different base-pairing interactions and forms a novel RNA fold composed exclusively of sheared G-A base pairs. From chemical-shift mapping we identified two Mg2+ binding sites in the active internal loop. One of the Mg2+ binding sites forms in the active but not the inactive conformation of the internal l

SUBMITTER: Hoffmann B 

PROVIDER: S-EPMC165820 | biostudies-literature | 2003 Jun

REPOSITORIES: biostudies-literature