title: Archaeal aminoacyl-tRNA synthetases interact with the ribosome to recycle tRNAs.
abstract: Aminoacyl-tRNA synthetases (aaRS) are essential enzymes catalyzing the formation of aminoacyl-tRNAs, the immediate precursors for encoded peptides in ribosomal protein synthesis. Previous studies have suggested a link between tRNA aminoacylation and high-molecular-weight cellular complexes such as the cytoskeleton or ribosomes. However, the structural basis of these interactions and potential mechanistic implications are not well understood. To biochemically characterize these interactions we have used a system of two interacting archaeal aaRSs: an atypical methanogenic-type seryl-tRNA synthetase and an archaeal ArgRS. More specifically, we have shown by thermophoresis and surface plasmon resonance that these two aaRSs bind to the large ribosomal subunit with micromolar affinities. We have identified the L7/L12 stalk and the proteins located near the stalk base as the main sites for aaRS binding. Finally, we have performed a bioinformatics analysis of synonymous codons in the Methanothermobacter thermautotrophicus genome that supports a mechanism in which the deacylated tRNAs may be recharged by aaRSs bound to the ribosome and reused at the next occurrence of a codon encoding the same amino acid. These results suggest a mechanism of tRNA recycling in which aaRSs associate with the L7/L12 stalk region to recapture the tRNAs released from the preceding ribosome in polysomes.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10000 Zagreb, Croatia, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland, Department of Molecular Biology, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10000 Zagreb, Croatia, Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia and Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
authors.forename: Vlatka
authors.initials: V
authors.lastname: Godinic-Mikulcic
authors.forename: Jelena
authors.initials: J
authors.lastname: Jaric
authors.forename: Basil J
authors.initials: BJ
authors.lastname: Greber
authors.forename: Vedran
authors.initials: V
authors.lastname: Franke
authors.forename: Vesna
authors.initials: V
authors.lastname: Hodnik
authors.forename: Gregor
authors.initials: G
authors.lastname: Anderluh
authors.forename: Nenad
authors.initials: N
authors.lastname: Ban
authors.forename: Ivana
authors.initials: I
authors.lastname: Weygand-Durasevic
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001105:Archaea / Q000201:enzymology*; D001126:Arginine-tRNA Ligase / Q000378:metabolism; D020745:Genome, Archaeal; D017013:Methanobacteriaceae / Q000235:genetics; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000201:enzymology*; D012714:Serine-tRNA Ligase / Q000378:metabolism
chemical_list: D012269:Ribosomal Proteins; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases; D012714:Serine-tRNA Ligase; D001126:Arginine-tRNA Ligase