A Cell Division Inhibitor SulA of Escherichia Coli Directly Interacts with FtsZ Through GTP Hydrolysis

E. coli SulA is an SOS-inducible protein that inhibits cell division. FtsZ is a protein that plays a central role in bacterial cell division. Using purified SulA protein that was fused to the maltose binding protein, we demonstrate in vitro that SulA interacts with FtsZ to form a stable complex. The reaction requires GTP and Mg ion. GDP and GTP gamma S cannot substitute for GTP, which suggests that hydrolysis of GTP is required for the reaction. The complex is formed in a molar ratio of approximately one to one of the two proteins. It is likely that the complex formation represents the in vivo mechanism by which SulA inhibits cell division.