Isolation and Characterization of a Phosphonomycin-Resistant Mutant of Escherichia coli K-12

Abstract

A mutant was isolated from Escherichia coli K-12 which showed increased resistance towards phosphonomycin, a new bactericidal antibiotic recently isolated from strains of Streptomyces . Evidence is presented which suggests that this mutant is resistant to lysis by phosphonomycin because of a lower affinity of phosphoenolpyruvate: uridine diphospho- N -acetylglucosamine enolpyruvyl transferase for this antibiotic. This mutant was also found to be temperature-sensitive in growth. At 42 C mutant cells grew poorly, and the rate of incorporation of 3 H-diaminopimelic acid into trichloroacetic acid-insoluble material was also greatly reduced. Genetic studies indicate that the increased resistance toward phosphonomycin and temperature sensitivity in growth of this mutant are probably the consequences of a single mutation.