ATPase component of the type IV pilus (T4P) that plays a role in surface and host cell adhesion, colonization, biofilm maturation, virulence, and twitching, a form of surface-associated motility facilitated by cycles of extension, adhesion, and retraction of T4P fibers (PubMed:10377148, PubMed:15629932, PubMed:18174131). Acts as a molecular motor to provide the energy that is required for T4P retraction while antagonist PilB ATPase activity is required for T4P extension (PubMed:26809217). Promotes also PilU retractation activity through direct interaction (PubMed:31626631). Homohexamer (PubMed:31626631). Interacts with PilU (Probable). Localizes to cell poles. The N-terminal region is responsible for proper localization to the piliated pole. Mutants retain surface pili but have lost twitching motility (PubMed:15629932). In a mouse model of acute pneumonia, a decreased colonization of the liver is observed but not of the lung relative to the parental strain (PubMed:10377148). Belongs to the GSP E family.