Loss of Pseudomonas aeruginosa PhpA aminopeptidase activity results in increased algD transcription

Inactivation of Pseudomonas aeruginosa phpA, encoding a putative leucine am inopeptidase, results in increased transcription of algD. The homologous pr otein in Escherichia coli, PepA, is multifunctional, possessing independent aminopeptidase and DNA-binding activities. Here we provide in vitro eviden ce that PhpA is an aminopeptidase and show that this activity is the releva nt property with regard to algD expression. This regulation occurred at the previously mapped algD transcription initiation site and was not due to ac tivation of an alternative promoter.