title: Elongation factor-P at the crossroads of the host-endosymbiont interface.
abstract: Elongation factor P (EF-P) is an ancient bacterial translational factor that aids the ribosome in polymerizing oligo-prolines. EF-P structurally resembles tRNA and binds in-between the exit and peptidyl sites of the ribosome to accelerate the intrinsically slow reaction of peptidyl-prolyl bond formation. Recent studies have identified in separate organisms, two evolutionarily convergent EF-P post-translational modification systems (EPMS), split predominantly between gammaproteobacteria, and betaproteobacteria. In both cases EF-P receives a post-translational modification, critical for its function, on a highly conserved residue that protrudes into the peptidyl-transfer center of the ribosome. EPMSs are comprised of a gene(s) that synthesizes the precursor molecule used in modifying EF-P, and a gene(s) encoding an enzyme that reacts with the precursor molecule to catalyze covalent attachment to EF-P. However, not all organisms genetically encode a complete EPMS. For instance, some symbiotic bacteria harbor efp and the corresponding gene that enzymatically attaches the modification, but lack the ability to synthesize the substrate used in the modification reaction. Here we highlight the recent discoveries made regarding EPMSs, with a focus on how these incomplete modification pathways shape or have been shaped by the endosymbiont-host relationship.
authors.affiliation: Molecular, Cellular and Developmental Biology Program, Ohio State University, Columbus, Ohio, USA.
authors.forename: Andrei
authors.initials: A
authors.lastname: Rajkovic
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, Ohio, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Witzky
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: William
authors.initials: W
authors.lastname: Navarre
authors.affiliation: Department of Microbiology, New York University School of Medicine, New York, New York, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Darwin
authors.affiliation: Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, Ohio, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Ibba
keywords: elongation factor-P; modification; rhamnosylation; translation