Structure of protein L7Ae bound to a K-turn derived from an archaeal box H/ACA sRNA at 1.8 A resolution

Structure. 2004 May;12(5):893-903. doi: 10.1016/j.str.2004.03.015.


The archaeal RNA binding protein L7Ae and its eukaryotic homolog 15.5 kDa/Snu13 recognize K-turns. This structural motif is canonically comprised of two stems (one with tandem A.G base pairs, the other with Watson-Crick pairs) linked by an asymmetric internal loop. L7Ae recognizes conventional K-turns in ribosomal and box C/D RNAs but also binds specifically to some box H/ACA RNAs at terminal stem loops. These have the A.G paired stem, but lack the Watson-Crick stem. The structure of Methanococcus jannaschii L7Ae bound to a symmetric duplex RNA without Watson-Crick stems demonstrates how a binding site for this component of diverse ribonucleoprotein complexes can be constructed with only the A.G stem and the loop. The RNA adopts a functional conformation with the aid of a base triple and tight binding of divalent cations. Comparison with the 15.5 kDa/Snu13-RNA complex structure suggests why the eukaryotic homolog does not recognize terminal stem loop L7Ae binding sites.

Publication types

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

MeSH terms

  • Magnetic Resonance Spectroscopy
  • Methanococcus / chemistry
  • Nucleic Acid Conformation
  • Protein Structure, Tertiary
  • RNA / chemistry
  • RNA / metabolism
  • Ribonucleoproteins / chemistry*
  • Ribonucleoproteins / metabolism
  • Ribosomal Proteins / chemistry*
  • Ribosomal Proteins / metabolism


  • Ribonucleoproteins
  • Ribosomal Proteins
  • RNA

Associated data

  • PDB/1SDS