Elongation Factor P is Dispensable in Escherichia coli and Pseudomonas aeruginosa

Abstract

Elongation factor P (EF-P) is a highly conservedribosomal initiation factor responsible for stimulating formation of the first peptide bond. Its essentiality has been debated and may differ depending on the organism. Here, we demonstrate that EF-P is dispensable in Escherichia coli and Pseudomonas aeruginosa under laboratory growth conditions. Although knockouts are viable, growth rates are diminished compared with wild-type strains. Despite this cost in fitness, these mutants are not more susceptible to a wide range of antibiotics; including ribosome targeting antibiotics, such as lincomycin, chloramphenicol, and streptomycin, which have been shown previously to disrupt EF-P function in vitro. In Pseudomonas, knockout of efp leads to an upregulation of mexX, a phenotype previously observed with other genetic lesions affecting ribosome function and that can be induced by the treatment with antibiotics affecting protein synthesis.