title: Mutations in ribosomal proteins L7/L12 perturb EF-G and EF-Tu functions.
abstract: In vitro cycling rates of E. coli ribosomes and of elongation factors EF-Tu and EF-G have been obtained and these are compatible with translation rates in vivo. We show that the rate of translocation is faster than 50 s-1 and therefore that the EF-G function is not a rate limiting step in protein synthesis. The in vivo phenotype of some L7/L12 mutants could be accounted for by perturbed EF-Tu as well as EF-G functions. The S12 mutants that we studied were, in contrast, only perturbed in their EF-Tu function, while their EF-G interaction was not impaired in relation to wild type ribosomes.
mesh_terms: D001426:Bacterial Proteins; D004926:Escherichia coli / Q000235:genetics*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D009154:Mutation; D010441:Peptide Chain Elongation, Translational; D020653:Peptide Elongation Factor G; D010444:Peptide Elongation Factor Tu / Q000502:physiology*; D010445:Peptide Elongation Factors / Q000502:physiology*; D014176:Protein Biosynthesis; D012269:Ribosomal Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D012269:Ribosomal Proteins; C016700:ribosomal protein L7-L12; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu