The Pseudomonas aeruginosa PsrA responds to long-chain fatty acid signals to regulate the fadBA5 beta-oxidation operon

Microbiology (Reading). 2008 Jun;154(Pt 6):1584-1598. doi: 10.1099/mic.0.2008/018135-0.


Beta-oxidative enzymes for fatty acid degradation (Fad) of long-chain fatty acids (LCFAs) are induced in vivo during lung infection in cystic fibrosis patients, and this may contribute to nutrient acquisition and pathogenesis of Pseudomonas aeruginosa. The promoter region of one P. aeruginosa beta-oxidation operon, fadBA5 (PA3014 and PA3013), was mapped. Focusing on the transposon mutagenesis of strain PAO1 carrying the P(fadBA5)-lacZ fusion, a regulator for the fadBA5 operon was identified to be PsrA (PA3006). Transcriptome analysis of the DeltapsrA mutant indicated its importance in regulating beta-oxidative enzymes. These microarray data were confirmed by real-time RT-PCR analyses of the fadB5 and lipA (encoding a lipase) genes. Induction of the fadBA5 operon was demonstrated to respond to novel LCFA signals, and this induction required the presence of PsrA, suggesting that LCFAs bind to PsrA to derepress fadBA5. Electrophoretic mobility shift assays indicate specific binding of PsrA to the fadBA5 promoter region. This binding is disrupted by specific LCFAs (C(18:1)(Delta9), C(16:0), C(14:0) and, to a lesser extent, C(12:0)), but not by other medium- or short-chain fatty acids or the first intermediate of beta-oxidation, acyl-CoA. It is shown here that PsrA is a fadBA5 regulator that binds and responds to LCFA signals in P. aeruginosa.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism*
  • Base Sequence
  • DNA-Binding Proteins / metabolism*
  • Fatty Acids / metabolism*
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial / genetics
  • Molecular Sequence Data
  • Operon / genetics*
  • Promoter Regions, Genetic / genetics
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / metabolism*
  • Signal Transduction
  • Transcription Factors / metabolism*


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Fatty Acids
  • PsrA protein, Pseudomonas
  • Transcription Factors

Associated data

  • GEO/GSE8083