Fig 3.

Growth of strains dependent on plasmid-encoded mutant BC proteins. Derivatives of the accBC deletion strain (AS109), cured of the S. enterica LT2 accBC operon by transduction, that contained plasmids encoding accB plus one of the accC alleles were grown in M9 minimal medium in a Bioscreen C analyzer with 0.4% glycerol as the primary carbon source and supplemented with either arabinose (Ara.) or glucose, as shown. The plasmids encoding the dimerization-deficient BC R19E and E23R mutant proteins were unable to allow growth (complement) at low levels of expression. Panel A shows growth of the strains in the absence of supplementation with arabinose or glucose. Panel B shows the strains grown with the addition of 0.8% glucose to repress expression from the araBAD promoter. Panel C shows the strains grown with 1.3 μM arabinose in addition to glycerol to give a low level of induction. Panel D shows the strains grown with the addition of 13 mM (0.2%) arabinose for maximum induction. The measurements were averages of at least 3 independent repetitions with 5 duplicates per repetition.