title: Regulation of methionyl-transfer ribonucleic acid synthetase formation in Escherichia coli and Salmonella typhimurium.
abstract: The control of methionyl-transfer ribonucleic acid (tRNA) synthetase (l-methionine: soluble RNA ligase [adenosine monophosphate]) was studied in methionyl-tRNA synthetase mutants of Escherichia coli and Salmonella typhimurium. The results of activity determinations with crude extracts indicate that this enzyme of the E. coli mutant strain possessed a reduced affinity for methionine-tRNA, whereas this enzyme of the S. typhimurium mutant exhibited a decreased affinity for l-methionine. The differential rate of methionyl-tRNA synthetase formation in these two mutants was several-fold greater than that of the respective parental strains. On the other hand, the level of in vivo aminoacylation of methionine-tRNA was only about one-third that of the parent strains. These results suggest that aminoacylation of methionine-tRNA is a necessary step in repression control of methionyl-tRNA synthetase of both E. coli and S. typhimurium strains.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000096:biosynthesis; D002247:Carbon Isotopes; D003470:Culture Media; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000201:enzymology*; D005001:Ethionine / Q000494:pharmacology; D007700:Kinetics; D008715:Methionine / Q000378:metabolism*; D009154:Mutation; D010084:Oxidation-Reduction; D012343:RNA, Transfer / Q000378:metabolism; D012486:Salmonella typhimurium / Q000201:enzymology*; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D003470:Culture Media; D012343:RNA, Transfer; D008715:Methionine; D000604:Amino Acyl-tRNA Synthetases; D005001:Ethionine