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 GTPγS 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.