title: Translation factor LepA contributes to tellurite resistance in Escherichia coli but plays no apparent role in the fidelity of protein synthesis.
abstract: LepA is a translational GTPase highly conserved in bacterial lineages. While it has been shown that LepA can catalyze reverse ribosomal translocation in vitro, the role of LepA in the cell remains unclear. Here, we show that deletion of the lepA gene (DeltalepA) in Escherichia coli causes hypersensitivity to potassium tellurite and penicillin G, but has no appreciable effect on growth under many other conditions. DeltalepA does not increase miscoding or frameshifting errors under normal or stress conditions, indicating that LepA does not contribute to the fidelity of translation. Overexpression of LepA interferes with tmRNA-mediated peptide tagging and A-site mRNA cleavage, suggesting that LepA is a bona fide translation factor that can act on stalled ribosomes with a vacant A site in vivo. Together these results lead us to hypothesize that LepA is involved in co-translational folding of proteins that are otherwise vulnerable to tellurite oxidation.
authors.affiliation: Department of Microbiology, The Ohio State University, Columbus, 43210, USA.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Shoji
authors.forename: Brian D
authors.initials: BD
authors.lastname: Janssen
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Hayes
authors.forename: Kurt
authors.initials: K
authors.lastname: Fredrick
mesh_terms: D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000172:deficiency / Q000235:genetics; D017353:Gene Deletion; D016877:Oxidants / Q000494:pharmacology; D010448:Peptide Initiation Factors; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D013691:Tellurium / Q000494:pharmacology*; D035602:Transcriptional Elongation Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C515651:LepA protein, E coli; D016877:Oxidants; D010448:Peptide Initiation Factors; D010750:Phosphoproteins; D012333:RNA, Messenger; D035602:Transcriptional Elongation Factors; C026899:potassium tellurate(IV); D020558:GTP Phosphohydrolases; C408370:typA protein, E coli; D013691:Tellurium