Entropic Contribution of Elongation Factor P to Proline Positioning at the Catalytic Center of the Ribosome.

The peptide bond formation with the amino acid proline (Pro) on the ribosome is slow, resulting in translational stalling when several Pro have to be incorporated into the peptide. Stalling at poly-Pro motifs is alleviated by the elongation factor P (EF-P). Here we investigate why Pro is a poor substrate and how EF-P catalyzes the reaction.

Elongation factor P: Function and effects on bacterial fitness.

The elongation phase of translation is promoted by three universal elongation factors, EF-Tu, EF-Ts, and EF-G in bacteria and their homologs in archaea and eukaryotes. Recent findings demonstrate that the translation of a subset of mRNAs requires a fourth elongation factor, EF-P in bacteria or the homologs factors a/eIF5A in other kingdoms of life. EF-P prevents the ribosome from stalling during the synthesis of proteins containing consecutive Pro residues, such as PPG, PPP, or longer Pro clusters.

EF-P is essential for rapid synthesis of proteins containing consecutive proline residues.

Elongation factor P (EF-P) is a translation factor of unknown function that has been implicated in a great variety of cellular processes. Here, we show that EF-P prevents ribosome from stalling during synthesis of proteins containing consecutive prolines, such as PPG, PPP, or longer proline strings, in natural and engineered model proteins. EF-P promotes peptide-bond formation and stabilizes the peptidyl-transfer RNA in the catalytic center of the ribosome.