YfmR is a translation factor that prevents ribosome stalling and cell death in the absence of EF-P.

Abstract

Protein synthesis is performed by the ribosome and a host of highly conserved elongation factors. Elongation factor P (EF-P) prevents ribosome stalling at difficult-to-translate sequences, such as polyproline tracts. In bacteria, phenotypes associated with <i>efp</i> deletion range from modest to lethal, suggesting that some species encode an additional translation factor that has similar function to EF-P. Here we identify YfmR as a translation factor that is essential in the absence of EF-P in <i>Bacillus subtilis</i>. YfmR is an ABCF ATPase that is closely related to both Uup and EttA, ABCFs that bind the ribosomal E-site and are conserved in more than 50% of bacterial genomes. We show that YfmR associates with actively translating ribosomes and that depleting YfmR from Δ<i>efp</i> cells causes severe ribosome stalling at a polyproline tract in vivo. YfmR depletion from Δ<i>efp</i> cells was lethal and caused reduced levels of actively translating ribosomes. Our results therefore identify YfmR as an important translation factor that is essential in <i>B. subtilis</i> in the absence of EF-P.