Assembly of core helices and rapid tertiary folding of a small bacterial group I ribozyme.

ABSTRACT: Compact but non-native intermediates have been implicated in the hierarchical folding of several large RNAs, but there is little information on their structure. In this article, ribonuclease and hydroxyl radical cleavage protection assays showed that base pairing of core helices stabilize a compact state of a small group I ribozyme from Azoarcus pre-tRNA(ile). Base pairing of the ribozyme core requires 10-fold less Mg(2+) than stable tertiary interactions, indicating that assembly of helices in the catalytic core represents a distinct phase that precedes the formation of native tertiary structure. Tertiary folding occurs in <100 ms at 37 degrees C. Such rapid folding is unprecedented among group I ribozymes and illustrates the association between structural complexity and folding time. A 3

SUBMITTER: Rangan P 

PROVIDER: S-EPMC149874 | biostudies-literature | 2003 Feb

REPOSITORIES: biostudies-literature