Bacteria use sophisticated nanomachines to secrete proteins across their cellular envelope. The terminal component of many of these systems is the bacterial secretin. Secretins form a homo-oligomeric pore in the outer membrane or Gram-negative bacteria. Secretins are utilised in the Type 2 secretion system, the Type 3 secretion system, Type 4 pili, and the export of filamentous phage. The Gram-negative type 2 secretion system is used to export a suite of fully folded enzymes and toxins to the extracellular environment. Here we present the structure of the secretin of the Pseudomonas aeruginosa type 2 secretion system responsible for the secretion of the exotoxin A and other proteins linked to parthenogenesis. We provide insights into how the disordered periplasmic domains have different symmetries and may interface with the inner membrane platform.