URACIL UPTAKE IN ESCHERICHIA-COLI K-12 - ISOLATION OF URAA MUTANTS AND CLONING OF THE GENE

Mutants defective in utilization of uracil at low concentrations have been isolated and characterized. The mutations in question (uraA) map close to the upp gene encoding uracil phosphoribosyltransferase. By co mplementation analysis, a plasmid that complements the uraA mutation h as been isolated. The uraA gene was shown to be the second gene in a b icistronic operon with upp as the promoter proximal gene, The nucleoti de sequence of the gene was determined, and the gene encodes a hydroph obic membrane protein with a calculated M(r) of 45,030. The UraA prote in has been identified in sodium dodecyl sulfate-polyacrylamide gels i n the membrane fraction of minicells harboring the uraA plasmids.