The secreton (type II secretion) and type IV pilus biogenesis branches of the general secretory pathway in Gram-negative bacteria share many features that suggest a common evolutionary origin. Five components of the secreton, the pseudopilins, are similar to subunits of type IV pili. Pseudopilin PulG is one of the secreton pseudopilins, and is found to assemble into pilus-like bundles. PulG interacts with proteins H, I and J within the multi-protein complex as well as blocking extracellular secretion and reducing the amount of PulE protein as well as the amounts of PulL, PulM, PulC and PulD when G is over-expressed. In Klebsiella the pilus-like structure is composed largely of PulG.