title: Kinetic analysis of an E.coli phenylalanine-tRNA synthetase mutant.
abstract: A mutation in the pheS gene, encoding phenylalanyl-tRNA synthetase, in E. coli NP37 confers temperature-sensitivity on the organism. A five-fold increase in tRNA(phe) levels complements the mutation. Analysis of the kinetic properties of the mutant enzyme indicates that the KM is 20-fold higher than the wild-type and the dissociation constant of the tRNA(phe)-synthetase complex for the mutant is at least 10-fold higher. These results indicate that the mutation in E. coli NP37 directly affects the tRNA(phe) binding site on the cognate synthetase.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005816:Genetic Complementation Test; D007700:Kinetics; D009154:Mutation; D010652:Phenylalanine-tRNA Ligase / Q000235:genetics* / Q000378:metabolism; D012345:RNA, Transfer, Amino Acid-Specific / Q000235:genetics*; D012360:RNA, Transfer, Phe / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
chemical_list: D012345:RNA, Transfer, Amino Acid-Specific; D012360:RNA, Transfer, Phe; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase