Interactions of the ribosome with mRNA and tRNA.

Recent collection of high-resolution crystal structures of the 70S ribosome with mRNA and tRNA substrates enhances our knowledge of protein synthesis principles. A novel network of interactions between the ribosome in the elongation state and mRNA downstream from the A codon suggests that mRNA is stabilized and aligned at the entrance to the decoding center. The X-ray studies clarify how natural modifications of tRNA are involved in the stabilization of the codon-anticodon interactions, prevention of frame-shifting and also expansion of the decoding capacity of tRNAs. In addition, the crystal structures provide the view that tRNA in the A and P sites communicate through a protein rich environment and suggest how these tRNAs are controlled through the intersubunit bridge formed by protein L31.