title: A conserved proline triplet in Val-tRNA synthetase and the origin of elongation factor P.
abstract: Bacterial ribosomes stall on polyproline stretches and require the elongation factor P (EF-P) to relieve the arrest. Yet it remains unclear why evolution has favored the development of EF-P rather than selecting against the occurrence of polyproline stretches in proteins. We have discovered that only a single polyproline stretch is invariant across all domains of life, namely a proline triplet in ValS, the tRNA synthetase, that charges tRNA(Val) with valine. Here, we show that expression of ValS in vivo and in vitro requires EF-P and demonstrate that the proline triplet located in the active site of ValS is important for efficient charging of tRNA(Val) with valine and preventing formation of mischarged Thr-tRNA(Val) as well as efficient growth of E. coli in vivo. We suggest that the critical role of the proline triplet for ValS activity may explain why bacterial cells coevolved the EF-P rescue system.
authors.affiliation: Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynen-Straße 25, 81377 Munich, Germany.
authors.forename: Agata L
authors.initials: AL
authors.lastname: Starosta
authors.affiliation: Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lassak
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH8 9YL, UK; Institute of Technology, University of Tartu, Tartu 50090, Estonia.
authors.forename: Lauri
authors.initials: L
authors.lastname: Peil
authors.affiliation: Institute of Technology, University of Tartu, Tartu 50090, Estonia; Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå 901 87, Sweden.
authors.forename: Gemma C
authors.initials: GC
authors.lastname: Atkinson
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Woolstenhulme
authors.affiliation: Institute of Molecular and Cell Biology, University of Tartu, Tartu 50090, Estonia.
authors.forename: Kai
authors.initials: K
authors.lastname: Virumäe
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
authors.forename: Allen
authors.initials: A
authors.lastname: Buskirk
authors.affiliation: Institute of Technology, University of Tartu, Tartu 50090, Estonia.
authors.forename: Tanel
authors.initials: T
authors.lastname: Tenson
authors.affiliation: Institute of Molecular and Cell Biology, University of Tartu, Tartu 50090, Estonia.
authors.forename: Jaanus
authors.initials: J
authors.lastname: Remme
authors.affiliation: Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, 82152 Martinsried, Germany; Center for Integrated Protein Science Munich (CiPSM) at the University of Munich, 80539 Munich, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Jung
authors.affiliation: Gene Center and Department for Biochemistry, University of Munich, Feodor-Lynen-Straße 25, 81377 Munich, Germany; Center for Integrated Protein Science Munich (CiPSM) at the University of Munich, 80539 Munich, Germany. Electronic address: wilson@lmb.uni-muenchen.de.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Wilson
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000235:genetics*; D014637:Valine-tRNA Ligase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; D010455:Peptides; C020746:factor EF-P; C011083:polyproline; D014637:Valine-tRNA Ligase