Fig 3.

citB mutant strains exhibit high levels of citrate synthase activity and protein levels in cell extracts. Strains were grown in DS medium, cells were harvested by centrifugation at the indicated time points, and crude cell extracts were generated. Separately, cell extracts were examined to determine the specific activity of citrate synthase (A) and the amount of CS protein (B). Cell extracts (0.25 to 0.5 μg) were analyzed by Western blotting using antibodies specific to CS and CodY (a loading control). Bands were quantitated, and values are presented as a ratio of CS to CodY, normalized to the ratio of the wild-type strain expression level at 2.5 h. Data from a representative experiment of two are shown. An immunoblot from a single time point (3 h) in a representative experiment is shown in the inset. The following strains were used: wild-type (KBP94), citB null (AWS174), citB2 (KBP118), citB7 (KBP81), and citAZ null (SJB67) strains.