Fig. 1. (a) Schematic of the haem acquisition system of Pseudomonas aeruginosa. Under low-iron conditions, apo-HasA (PDB ID: 3MOK) secreted by P. aeruginosa captures and transports haem (holo-HasA, PDB ID: 3ELL) to the HasA specific receptor HasR expressed on outer membrane. (b) The structure of haem (left) and metallo-9,10,19,20-tetraphenylporphycene (right).
