FIGURE 3.

FtsQ_SH8 Y248Bpa is not functional. A, FtsQ temperature-sensitive E. coli strain LMC531 harboring a Bpa-specific suppressor vector and a vector for the expression of SH8ftsQ, as indicated, were grown at the non-permissive temperature (37 °C) in the absence or presence of Bpa. Bpa-dependent complementation was observed with position 250 of FtsQ_SH8 encoded by an amber codon (SH₈ftsQ 250amber), indicating that mutant FtsQ_SH8 S250Bpa is functional. No complementation was observed with the similarly encoded position 248. B, E. coli strain LMC531 harboring a vector encoding wild-type FtsQ_SH8 (SH₈ftsQ wild type) or FtsQ_SH8 Y248* (SH₈ftsQ 248stop) were grown at the permissive temperature (30 °C) under non-inducing and inducing conditions. Rhamnose-induced expression of FtsQ_SH8 Y248* inhibited cell division, indicating a dominant negative effect as described previously (24, 38). EV, empty vector. Scale bars = 4 μm.