Incorporation of aminoacyl-tRNA into the ribosome as seen by cryo-electron microscopy

Nat Struct Biol. 2003 Nov;10(11):899-906. doi: 10.1038/nsb1003. Epub 2003 Oct 19.


Aminoacyl-tRNAs (aa-tRNAs) are delivered to the ribosome as part of the ternary complex of aa-tRNA, elongation factor Tu (EF-Tu) and GTP. Here, we present a cryo-electron microscopy (cryo-EM) study, at a resolution of approximately 9 A, showing that during the incorporation of the aa-tRNA into the 70S ribosome of Escherichia coli, the flexibility of aa-tRNA allows the initial codon recognition and its accommodation into the ribosomal A site. In addition, a conformational change observed in the GTPase-associated center (GAC) of the ribosomal 50S subunit may provide the mechanism by which the ribosome promotes a relative movement of the aa-tRNA with respect to EF-Tu. This relative rearrangement seems to facilitate codon recognition by the incoming aa-tRNA, and to provide the codon-anticodon recognition-dependent signal for the GTPase activity of EF-Tu. From these new findings we propose a mechanism that can explain the sequence of events during the decoding of mRNA on the ribosome.

Publication types

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

MeSH terms

  • Cryoelectron Microscopy
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli / ultrastructure
  • GTP Phosphohydrolases / metabolism
  • Nucleic Acid Conformation
  • Protein Structure, Tertiary
  • RNA, Transfer, Amino Acyl / metabolism*
  • RNA, Transfer, Amino Acyl / ultrastructure
  • Ribosomes / metabolism*
  • Ribosomes / ultrastructure


  • RNA, Transfer, Amino Acyl
  • GTP Phosphohydrolases

Associated data

  • PDB/1FFK
  • PDB/1IBM
  • PDB/1OB2
  • PDB/1QZA
  • PDB/1QZB
  • PDB/1QZC
  • PDB/1QZD
  • PDB/1R2W
  • PDB/1R2X