Fig 4.

In vivo stability of the MetE mutants. Cells of the WE (filled circles), WE-214 (open circles), WE-CA (filled triangles), and WE-214A (open triangles) strains growing exponentially (OD₆₀₀ of 0.3) at 37°C in M9 glucose medium with pH values of 6.0 (a) or 7.0 (b) were treated with 200 μg chloramphenicol ml⁻¹, and then one-half of the pH 7.0 culture was shifted to 45°C (c). Samples were collected at the indicated time points and analyzed via Western blotting, as described in Materials and Methods. The densitometry results were normalized by setting the MetE level prior to chloramphenicol addition equal to 100%.