title: Effect of chloride and glutamate ions on in vitro protein synthesis by the moderate halophile Vibrio costicola.
abstract: Vibrio costicola grown in the presence of different NaCl concentrations contains cell-associated Na+ and K+ ions whose sum is equal to or greater than the external Na+ concentration. In the presence of 0.5 M NaCl, virtually no in vitro protein is synthesized in extracts of cells grown in 1.0 M NaCl. However, we report here that active in vitro protein synthesis occurred in 0.6 M or higher concentrations of Na2SO4, sodium formate, sodium acetate, sodium aspartate, or sodium glutamate, whereas 0.6 M NaF, NaCl, or NaBr completely inhibited protein synthesis as measured by polyuridylic acid-directed incorporation of [14C]phenylalanine. Sodium glutamate, sodium aspartate, and betaine (0.3 M) counteracted the inhibitory action of 0.6 M NaCl. The cell-associated Cl- concentration was 0.22 mol/kg in cells grown in 1.0 M NaCl. Of this, the free intracellular Cl- concentration was only 0.02 mol/kg. Cells contained 0.11 mol of glutamate per kg and small concentrations of other amino acids. All of the negative counterions for cell-associated Na+ and K+ have not yet been determined. In vitro protein synthesis by Escherichia coli was inhibited by sodium glutamate. Hybridization experiments with ribosomes and the soluble (S-100) fractions from extracts of E. coli and V. costicola showed that the glutamate-sensitive fraction was found in the soluble, not the ribosomal, part of the system. The phenylalanyl-tRNA synthetase of V. costicola was not inhibited by 0.5 M or higher concentrations of NaCl; it was slightly more sensitive to high concentrations of sodium glutamate. Therefore, this enzyme was not responsible for the salt response of the V. costicola in vitro protein-synthesizing system.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000838:Anions; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002712:Chlorides / Q000378:metabolism / Q000494:pharmacology*; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D006217:Halobacterium / Q000378:metabolism; D009994:Osmolar Concentration; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D014733:Vibrio / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D000838:Anions; D001426:Bacterial Proteins; D002712:Chlorides; D005971:Glutamates; D018698:Glutamic Acid; D012965:Sodium Chloride; D010652:Phenylalanine-tRNA Ligase