Viability of E. coli VIP2 cells expressing FtsZ mutants. Exponentially-grown cells of E. coli VIP5 without (−) or with plasmids that express wild-type FtsZ (WT), FtsZ(E83Q) or FtsZ(R85Q) were plated by duplicate on two LB agar plates and incubated at 42°C or 30°C. Cell viability was determined the following day. The average and the standard deviation (SD) of 3 independent experiments were obtained using the program EXCEL. The H3 bend mutations cause significant decrease in cell viability.