A magnesium ion core at the heart of a ribozyme domain

Nat Struct Biol. 1997 Jul;4(7):553-8. doi: 10.1038/nsb0797-553.


Large ribozymes require divalent metal ions to fold. We show here that the tertiary structure of the Tetrahymena group I intron P4-P6 domain nucleates around a magnesium ion core. In the domain crystal structure, five magnesium ions bind in a three-helix junction at the centre of the molecule. Single atom changes in any one of four magnesium sites in this three-helix junction destroy folding of the entire 160-nucleotide P4-P6 domain. The magnesium ion core may be the RNA counterpart to the protein hydrophobic core, burying parts of the RNA molecule in the native structure.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Crystallography, X-Ray
  • Introns
  • Magnesium / chemistry
  • Magnesium / metabolism*
  • Models, Molecular
  • Nucleic Acid Conformation
  • Phosphates / chemistry
  • RNA, Catalytic / chemistry*
  • RNA, Catalytic / metabolism*
  • Tetrahymena / genetics
  • Thionucleotides / chemistry


  • Phosphates
  • RNA, Catalytic
  • Thionucleotides
  • Magnesium