PtrA Is a Periplasmic Protein Involved in Cu Tolerance in Pseudomonas aeruginosa

In this work, we demonstrate that PtrA (U. H. Ha et al., Mol. Microbiol. 54:307-320, 2004) is a periplasmic protein, specifically synthesized in the presence of copper, that is involved in the tolerance of Pseudomonas aeruginosa to copper. Our biochemical and genetic analyses challenge its role in transcriptional inhibition of the type III secretion system.