Fig. 5.

Growth curves of BL21-DE3-ΔE1 cells harboring either pRSETB-Y-EI (Upper) or pRSETB-Y-EI H189Q (Lower). The cells were grown in LB medium, and when the OD₄₂₀ was 1.0 for each culture, IPTG (0.5 mM) was added as denoted by the arrows. Samples were removed at the indicated times to determine the OD₄₂₀ (left ordinate, □, ▵) and the percentage of cells that exhibited a bipolar distribution of fluorescence (right ordinate, ▪, ▴). Although ≈99% of Y-EI-containing cells showed a polar distribution at 2 h after addition of IPTG, essentially all H189Q-containing cells showed a diffuse distribution.