Core component of the type II secretion system required for the energy-dependent secretion of extracellular factors such as proteases and toxins from the periplasm. Pseudopilin (pilin-like) protein that polymerizes to form the pseudopilus. Further polymerization triggers pseudopilus growth. Type II secretion system is composed of four main components: the outer membrane complex, the inner membrane complex, the cytoplasmic secretion ATPase and the periplasm-spanning pseudopilus. Forms homomultimers. Silenced by the DNA-binding protein H-NS under standard growth conditions. Cleaved by the prepilin peptidase. Methylated by prepilin peptidase at the amino group of the N-terminal phenylalanine once the leader sequence is cleaved. Part of a cryptic operon that encodes proteins involved in type II secretion machinery in other organisms, but is not expressed in strain K12. Belongs to the GSP G family.