The isolation and mapping of EF-Tu mutations in Salmonella typhimurium

The first isolation of EF-Tu mutations in Salmonella typhimurium is reported. The mutations were isolated by selecting for resistance to the antibiotic mocimycin (= kirromycin). The mocimycin resistant phenotype is the result of mutations in each of two genes, tufA and tufB. Strains mutant in only one of the two tuf genes are sensitive to mocimycin. The spontaneous mutation rate of each of the two tuf genes to a mocimycin resistant phenotype differs by an order of magnitude. tufA maps at minute 71-72, closely linked to rpsL. tufB maps at minute 88-89, closely linked to rpoB. These map positions correspond to the locations of tufA and tufB in E. coli.