Poster Presentation The 43rd Lorne Conference on Protein Structure and Function 2018

Structure of a Pseudomonas aeruginosa toxin secretin (#178)

Iain D Hay 1 , Matthew Belousoff 1 , Trevor Lithgow 1
  1. Monash University, Infection & Immunity Program, Biomedicine Discovery Institute & Dept of Microbiology, Clayton, VIC, Australia

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.