Minor groove RNA triplex in the crystal structure of a ribosomal frameshifting viral pseudoknot

Li Su, Liqing Chen, Martin Egli, James M. Berger, Alexander Rich

Research output: Contribution to journalArticle


Many viruses regulate translation of polycistronic mRNA using a -1 ribosomal frameshift induced by an RNA pseudoknot. A pseudoknot has two stems that form a quasi-continuous helix and two connecting loops. A 1.6 Å crystal structure of the beet western yellow virus (BWYV) pseudoknot reveals rotation and a bend at the junction of the two stems. A loop base is inserted in the major groove of one stem with quadruple-base interactions. The second loop forms a new minor-groove triplex motif with the other stem, involving 2'-OH and triple-base interactions, as well as sodium ion coordination. Overall, the number of hydrogen bonds stabilizing the tertiary interactions exceeds the number involved in Watson-Crick base pairs. This structure will aid mechanistic analyses of ribosomal frameshifting.

Original languageEnglish (US)
Pages (from-to)285-292
Number of pages8
JournalNature structural biology
Issue number3
StatePublished - Mar 10 1999


ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Genetics

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