title: Temperature-sensitive relaxed Phenotype in a stringent strain of Escherichia coli.
abstract: A temperature-sensitive elongation factor G (EF-G) mutation carried by a rel strain of Escherichia coli was transferred to a rel(+) strain. The recombinant (AA-10) was found to be temperature-sensitive "relaxed" for ribonucleic acid (RNA) regulation. However, when a temperature-sensitive EF-G is present in a strain temperature-sensitive for valyl-transfer RNA (tRNA) synthetase, this new strain (AA-16) is no longer temperature-sensitive "relaxed" for RNA regulation. In strain AA-10, all tRNAs remain fully charged, and in AA-16 tRNA(val) becomes completely discharged at the nonpermissive growth temperature. Also, synthesis of ppGpp is not observed in strain AA-10 at 42 C but is observed at 42 C in strain AA-16.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000096:biosynthesis; D002247:Carbon Isotopes; D002474:Cell-Free System; D004926:Escherichia coli / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D007532:Isoleucine / Q000378:metabolism; D009154:Mutation; D010452:Peptide Biosynthesis; D010445:Peptide Elongation Factors; D010641:Phenotype; D010649:Phenylalanine / Q000378:metabolism; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012343:RNA, Transfer; D011995:Recombination, Genetic; D013696:Temperature; D014161:Transduction, Genetic; D014316:Tritium; D014498:Uracil / Q000378:metabolism; D014529:Uridine / Q000378:metabolism; D014633:Valine / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D010445:Peptide Elongation Factors; D012329:RNA, Bacterial; D007532:Isoleucine; D014316:Tritium; D010649:Phenylalanine; D014498:Uracil; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases; D014633:Valine; D014529:Uridine