Discovery of an operon that participates in agmatine metabolism and regulates biofilm formation in Pseudomonas aeruginosa.
Agmatine is the decarboxylation product of arginine and a number of bacteria have devoted enzymatic pathways for its metabolism. Pseudomonas aeruginosa harbours the aguBA operon that metabolizes agmatine to putrescine, which can be subsequently converted into other polyamines or shunted into the TCA cycle for energy production. We discovered an alternate agmatine operon in the P. aeruginosa strain PA14 named agu2ABCA' that contains two genes for agmatine deiminases (agu2A and agu2A'). This operon was found to be present in 25% of clinical P. aeruginosa isolates. Agu2A' contains a twin-arginine translocation signal at its N-terminus and site-directed mutagenesis and cell fractionation experiments confirmed this protein is secreted to the periplasm. Analysis of the agu2ABCA' promoter demonstrates that agmatine induces expression of the operon during the stationary phase of growth and during biofilm growth and agu2ABCA' provides only weak complementation of aguBA, which is induced during log phase. Biofilm assays of mutants of all three agmatine deiminase genes in PA14 revealed that deletion of agu2ABCA', specifically its secreted product Agu2A', reduces biofilm production of PA14 following addition of exogenous agmatine. Together, these findings reveal a novel role for the agu2ABCA' operon in the biofilm development of P. aeruginosa.
Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Minnesota, Minneapolis, MN 55455, USA. bjwillia@umn.edu
Bryan J
BJ
Williams
Rui-Hong
RH
Du
M Wade
MW
Calcutt
Rasul
R
Abdolrasulnia
Brian W
BW
Christman
Timothy S
TS
Blackwell
D000376:Agmatine / Q000378:metabolism*; D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development*; D002458:Cell Fractionation; D020869:Gene Expression Profiling; D023061:Gene Order; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009876:Operon; D019897:Periplasm / Q000201:enzymology; D011401:Promoter Regions, Genetic; D021382:Protein Sorting Signals; D021381:Protein Transport; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
D021382:Protein Sorting Signals; D000376:Agmatine; D006867:Hydrolases; C019626:agmatine deiminase