Genetic characterization of Salmonella typhimurium LT2 ara mutations

Seventeen independently isolated L-arabinose utilization-deficient mutants of Salmonella typhimurium LT2 were characterized. Four complementation groups (araA, araB, araC, and araD) were identified and were equivalent to the same genes in the ara system in Escherichia coli. The order of the four genes was determined to be araD-araA-araB-araC-leu. Two transcription units were found: the araBAD operon was transcribed counterclockwise, and the araC gene was transcribed clockwise.