FtsZ, which is an essential participant in prokaryotic cell division, forms a filamentous ring structure that involves guanosine 5 -triphosphate (GTP)-dependent polymerization

division, forms a filamentous ring structure that involves guanosine 5 -triphosphate (GTP)-dependent polymerization at the mid cell before division in Escherichia coli (E. coli). It is known that polymerization and de-polymerization of FtsZ polymer occur frequently in vivo. It has been indicated that small molecular compounds, which inhibit FtsZ activity, have a potential as novel antibacterial drugs. Information about regulation mechanism of FtsZ polymerization should be useful for development of a new class of antibacterial drug. The stability of FtsZ polymer is regulated by several inhibitory and stimulatory proteins in vivo. Moreover, inhibition of FtsZ polymerization by MinC protein is responsible for controlling the site of cell division. Thus, MinC is recruited to the inner membrane surface near the cell pole under the control of MinD and MinE to prevent septum ring formation near the cell pole. Recent studies using sedimentation and electron microscopic methods suggested that MinC interacts with the FtsZ polymer and inhibits further FtsZ polymerization. However, details about the interaction between MinC and FtsZ were still unclear because no techniques had yet been developed for direct observation of molecular interaction between MinC and FtsZ in the reaction solution. The present study describes the development of a direct monitoring technique and its successful application to characterize the interaction between MinC and FtsZ in solution by fluorescence resonance energy transfer (FRET).