title: Discrimination between bromouracil and thymine for uptake into DNA in drm- and dra- mutants of Escherichia coli K12.
abstract: The relative efficiency of bromouracil and thymine for uptake into DNA was measured in various thymine-requiring strains of Escherichia coli K12. It was found that: 1. Mutants with genotype thyA- dra- discriminate against bromouracil to much greater extent than do mutants with genotype thyA- drm-. 2. The discrimination in dra-mutants is dependent on thymine concentration, whereas discrimination in drm- mutants is almost independent of thymine concentration. It is suggested that the intracellular level of deoxyribose 5-phosphate affects the efficiency of uptake into DNA of bromouracil relative to thymine.
mesh_terms: D001976:Bromouracil / Q000378:metabolism*; D004269:DNA, Bacterial / Q000096:biosynthesis*; D003855:Deoxyribose / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005838:Genotype; D009154:Mutation; D013941:Thymine / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D001976:Bromouracil; D003855:Deoxyribose; D013941:Thymine