Metal ions and flexibility in a viral RNA pseudoknot at atomic resolution

Martin Egli*, George Minasov, Li Su, Alexander Rich

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

100 Scopus citations


Many pathogenic viruses use programmed -1 ribosomal frameshifting to regulate translation of their structural and enzymatic proteins from polycistronic mRNAs. Frameshifting is commonly stimulated by a pseudoknot located downstream from a slippery sequence, the latter positioned at the ribosomal A and P sites. We report here the structures of two crystal forms of the frameshifting RNA pseudoknot from beet western yellow virus at resolutions of 1.25 and 2.85 Å. Because of the very high resolution of 1.25 Å, ten mono- and divalent metal ions per asymmetric unit could be identified, giving insight into potential roles of metal ions in stabilizing the pseudoknot. A magnesium ion located at the junction of the two pseudoknot stems appears to play a crucial role in stabilizing the structure. Because the two crystal forms exhibit mostly unrelated packing interactions and local crystallographic disorder in the high-resolution form was resolvable, the two structures offer the most detailed view yet of the conformational preference and flexibility of an RNA pseudoknot.

Original languageEnglish (US)
Pages (from-to)4302-4307
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Apr 2 2002


  • Metal ion coordination
  • RNA tertiary structure
  • Ribosomal frameshifting
  • X-ray crystallography

ASJC Scopus subject areas

  • General


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