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

Prashanth Rangan, Benoît Masquida, Eric Westhof, Sarah A. Woodson

Research output: Contribution to journalArticlepeer-review


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-tRNAile. Base pairing of the ribozyme core requires 10-fold less Mg2+ 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°C. Such rapid folding is unprecedented among group I ribozymes and illustrates the association between structural complexity and folding time. A 3D model of the Azoarcus ribozyme was constructed by identifying homologous sequence motifs in rRNA. The model reveals distinct structural features, such as a large interface between the P4-P6 and P3-P9 domains, that may explain the unusual stability of the Azoarcus ribozyme and the cooperativity of folding.

Original languageEnglish (US)
Pages (from-to)1574-1579
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number4
StatePublished - Feb 18 2003


  • Hydroxyl radical footprinting
  • Metal ions
  • RNA modeling
  • RNA structure

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Assembly of core helices and rapid tertiary folding of a small bacterial group I ribozyme'. Together they form a unique fingerprint.

Cite this