The solution structure of ribosomal protein L18 from Thermus thermophilus reveals a conserved RNA-binding fold

Biochem J. 2002 May 1;363(Pt 3):553-61. doi: 10.1042/0264-6021:3630553.


We have determined the solution structure of ribosomal protein L18 from Thermus thermophilus. L18 is a 12.5 kDa protein of the large subunit of the ribosome and binds to both 5 S and 23 S rRNA. In the uncomplexed state L18 folds to a mixed alpha/beta globular structure with a long disordered N-terminal region. We compared our high-resolution structure with RNA-complexed L18 from Haloarcula marismortui and T. thermophilus to examine RNA-induced as well as species-dependent structural differences. We also identified T. thermophilus S11 as a structural homologue and found that the structures of the RNA-recognition sites are conserved. Important features, for instance a bulge in the RNA-contacting beta-sheet, are conserved in both proteins. We suggest that the L18 fold recognizes a specific RNA motif and that the resulting RNA-protein-recognition module is tolerant to variations in sequence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Haloarcula marismortui / chemistry
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Weight
  • RNA, Bacterial / metabolism*
  • Ribosomal Proteins / chemistry*
  • Structure-Activity Relationship
  • Thermus thermophilus / chemistry*


  • RNA, Bacterial
  • Ribosomal Proteins
  • ribosomal protein L18