RNA folds: insights from recent crystal structures

Annu Rev Biophys Biomol Struct. 1999:28:57-73. doi: 10.1146/annurev.biophys.28.1.57.


An RNA fold is the result of packing together two or more coaxial helical stacks. To date, four RNA folds have been determined at near-atomic resolution by X-ray crystallography: transfer RNA, the hammerhead ribozyme, the P4-P6 domain of the Tetrahymena group I intron, and the hepatitis delta virus ribozyme. All four folds result in RNAs that are considerably more compact than isolated A-form duplexes. These structures illustrate, to varying degrees, three modes of fold stabilization: association of complementary molecular surfaces, stabilization of close RNA packing by binding of cations, and stabilization through pseudoknotting.

Publication types

  • Review

MeSH terms

  • Animals
  • Base Sequence
  • Crystallography, X-Ray / methods
  • Hepatitis Delta Virus / genetics
  • Introns
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation*
  • RNA / chemistry*
  • RNA, Catalytic / chemistry
  • Tetrahymena / genetics


  • RNA, Catalytic
  • RNA