A Multisite-Mutation Map of the Leucine Operon of Salmonella Typhimurium

LEUCINE is synthesized in Salmonella typhimurium by the pathway shown in Figure The genes specifying the leucine-forming enzymes are clustered in one region of the genome between ara and azi and comprise an operon (MARGOLIN 1963; BURNS, CALVO, MARGOLIN and UMBARGER 1966; CALVO, MARGOLIN and UMBARGER 1969). We describe here the isolation and characterization of a large number of leucine auxotrophs and the construction of a detailed multisite-mutation map of the leucine operon.