Structural study of the tmRNA- SmpB complex with the stalled ribosome of Pseudomonas aeruginosa and Enterococcus faecium

Protein synthesis or translation, takes place on the ribosome. However, due to various stresses stalling of the ribosomes does often occur on mRNAs devoid of a terminating stop codon. All bacteria share a common unique biological mechanism for rescuing stalled ribosomes on a non-stop mRNA, called trans-translation and based on the transfer – messenger RNA (tmRNA) and the protein SmpB. Our precedent cryo-EM studies has already revealed the molecular basis of this mechanism in Escherichia coli. However, no one has yet clarified how tmRNA – SmpB intervenes on the ribosome during trans-translation on pathogenic bacteria. The proposed project aims at studying the molecular interactions between tmRNA-SmpB complexes and stalled ribosomes in six ESKAPE pathogens. This deep structural understanding of trans-translation in each ESKAPE pathogens will clarify the molecular basis for the specificity in trans-translation and help with the development of new antibiotics.