title: Sub-Cellular Localization and Complex Formation by Aminoacyl-tRNA Synthetases in Cyanobacteria: Evidence for Interaction of Membrane-Anchored ValRS with ATP Synthase.
abstract: tRNAs are charged with cognate amino acids by aminoacyl-tRNA synthetases (aaRSs) and subsequently delivered to the ribosome to be used as substrates for gene translation. Whether aminoacyl-tRNAs are channeled to the ribosome by transit within translational complexes that avoid their diffusion in the cytoplasm is a matter of intense investigation in organisms of the three domains of life. In the cyanobacterium Anabaena sp. PCC 7120, the valyl-tRNA synthetase (ValRS) is anchored to thylakoid membranes by means of the CAAD domain. We have investigated whether in this organism ValRS could act as a hub for the nucleation of a translational complex by attracting other aaRSs to the membranes. Out of the 20 aaRSs, only ValRS was found to localize in thylakoid membranes whereas the other enzymes occupied the soluble portion of the cytoplasm. To investigate the basis for this asymmetric distribution of aaRSs, a global search for proteins interacting with the 20 aaRSs was conducted. The interaction between ValRS and the FoF1 ATP synthase complex here reported is of utmost interest and suggests a functional link between elements of the gene translation and energy production machineries.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla Seville, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Santamaría-Gómez
authors.affiliation: Facultad de Formación del Profesorado, Universidad de Extremadura Cáceres, Spain.
authors.forename: Jesús A G
authors.initials: JA
authors.lastname: Ochoa de Alda
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla Seville, Spain.
authors.forename: Elvira
authors.initials: E
authors.lastname: Olmedo-Verd
authors.affiliation: Department of Agrochemistry and Biochemistry, Faculty of Science, University of Alicante Alicante, Spain.
authors.forename: Roque
authors.initials: R
authors.lastname: Bru-Martínez
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla Seville, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Luque
keywords: CAAD; FoF1 ATP synthase; aminoacyl-tRNA synthetases; cyanobacteria; membrane-anchoring; thylakoids