title: Isolation and characterization of an Escherichia coli mutant deficient in dTMP kinase activity.
abstract: Escherichia coli LD0181 is sensitive to 15 micrograms of 2',3'-dideoxythymidine per ml. A derivative that was resistant to 40 micrograms of the same chemical per ml at 30 degrees C and that had lost the ability to grow on enriched medium at 42 degrees C was isolated after nitroso-guanidine mutagenesis. This mutant, TD105, produced a dTMP kinase with 25-fold lower specific activity and a 5-fold higher Km for dTMP than the parental strain. The dTMP pool in TD105 was 4.4-fold higher than in the parent. In addition to temperature sensitivity and resistance to 2',3'-dideoxythymidine, the mutant exhibited a hypersensitivity to 5-bromo-2'-deoxyuridine. All three of these phenotypes are cotransducible. The tmk gene was mapped by cotransduction to approximately 30 min on the E. coli map.
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D005838:Genotype; D007700:Kinetics; D009703:Nucleoside-Phosphate Kinase / Q000302:isolation & purification* / Q000378:metabolism; D010770:Phosphotransferases / Q000302:isolation & purification*; D013696:Temperature; D013938:Thymidine Monophosphate / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D013938:Thymidine Monophosphate; D010770:Phosphotransferases; D009703:Nucleoside-Phosphate Kinase; C020093:dTMP kinase