Septum site-determining protein MinD is part of the operon MinCDE that determines the site of the formation of a septum at mid-cell, an important part of bacterial cell division. MinC is a nonspecific inhibitor of the septum protein FtsZ. MinE is the supressor of MinC. MinD plays a pivotal role, selecting the mid-cell over other sites through the activation and regulation of MinC and MinE. MinD is a membrane-associated ATPase, related to nitrogenase iron protein.