Formation of the First Peptide Bond: The Structure of EF-P Bound to the 70 S Ribosome

Abstract

Protein Synthesis Initiation Complex: The final step in the initiation phase of protein synthesis is the formation of the first peptide bond, which requires initiator transfer RNA (tRNA) to be bound at the ribosomal P site. Elongation factor P (EF-P) is a protein conserved in all eubacteria that stimulates this initial bond formation. Insight into how this is achieved comes from a structure of Thermus thermophilus 70 S ribosome bound to EF-P, initiator tRNA, and a short piece of messenger RNA presented by Blaha et al. (p. 966 ). EF-P binds between the P and E sites and facilitates proper positioning of initiator tRNA in the P site. A similar mechanism is likely to apply to structurally homologous initiation factors in archea and eukarya.