Type 4 Pilus Biogenesis and Type II-Mediated Protein Secretion byVibrio choleraeOccur Independently of the TonB-Facilitated Proton Motive Force

In Vibrio cholerae, elaboration of toxin-coregulated pilus and protein secretion by the extracellular protein secretion apparatus occurred in the absence of both TonB systems. In contrast, the cognate putative ATPases were required for each process and could not substitute for each other.