Decrypting the functional design of unmodified translation elongation factor P
Stalling of ribosomes during polypeptide synthesis due to consecutive proline motifs is a challenge faced by organisms across all kingdoms. To overcome this, bacteria employ translation elongation factor P (EF-P), while archaea and eukaryotes rely on a/eIF5A. Typically, these elongation factors become active only after undergoing post-translational modifications (PTMs) such as beta-lysinylation, (deoxy-)hypusinylation, rhamnosylation, or 5-aminopentanolyation. An exception to this rule is found in EF-P members of the PGKGP-subfamily, which remain unmodified. However, the mechanism behind the ability of certain bacteria to avoid metabolically and energetically costly PTMs, while retaining active EF-P, remains unclear. In this study, we investigated the design principles governing the full functionality of unmodified EF-Ps in Escherichia coli. We first screened for naturally unmodified EF-Ps that are active in an E. coli reporter strain. We identified EF-P from Rhodomicrobium vannielii c
