Translation elongation factor P (EF-P)

ABSTRACT Translation elongation factor P (EF-P) is conserved in all three domains of life (called eIF5A and aIF5A in eukaryotes and archaea, respectively) and functions to alleviate ribosome pausing during the translation of specific sequences, including consecutive proline residues. EF-P was identified in 1975 as a factor that stimulated the peptidyltransferase reaction in vitro but its involvement in the translation of tandem proline residues was not uncovered until 2013. Throughout the four decades of EF-P research, perceptions of EF-P function have changed dramatically. In particular, while EF-P was thought to potentiate the formation of the first peptide bond in a protein, it is now broadly accepted to act throughout translation elongation. Further, EF-P was initially reported to be essential, but recent work has shown that the requirement of EF-P for growth is conditional. Finally, it is thought that post-translational modification of EF-P is strictly required for its function but recent studies suggest that EF-P modification may play a more nuanced role in EF-P activity. Here, we review the history of EF-P research, with an emphasis on its initial isolation and characterization as well as the discoveries that altered our perceptions of its function.

Complex Structure of Pseudomonas aeruginosa Arginine Rhamnosyltransferase EarP with Its Acceptor Elongation Factor P

ABSTRACT A bacterial inverting glycosyltransferase EarP transfers rhamnose from dTDP-β-l-rhamnose (TDP-Rha) to Arg32 of translation elongation factor P (EF-P) to activate its function. We report here the structural and biochemical characterization of Pseudomonas aeruginosa EarP. In contrast to recently reported Neisseria meningitidis EarP, P. aeruginosa EarP exhibits differential conformational changes upon TDP-Rha and EF-P binding. Sugar donor binding enhances acceptor binding to EarP, as revealed by structural comparison between the apo-, TDP-Rha-, and TDP/EF-P-bound forms and isothermal titration calorimetry experiments. In vitro EF-P rhamnosylation combined with active-site geometry indicates that Asp16 corresponding to Asp20 of N. meningitidis EarP is the catalytic base, whereas Glu272 is another putative catalytic residue. Our study should provide the basis for EarP-targeted inhibitor design against infections from P. aeruginosa and other clinically relevant species. IMPORTANCE Posttranslational rhamnosylation of EF-P plays a key role in Pseudomonas aeruginosa, establishing virulence and antibiotic resistance, as well as survival. The detailed structural and biochemical characterization of the EF-P-specific rhamnosyltransferase EarP from P. aeruginosa not only demonstrates that sugar donor TDP-Rha binding enhances acceptor EF-P binding to EarP but also should provide valuable information for the structure-guided development of its inhibitors against infections from P. aeruginosa and other EarP-containing pathogens.