Nocardamine-dependent iron uptake in Pseudomonas aeruginosa : exclusive implication of the FoxA outer membrane transporter
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ABSTRACT: Iron is a key nutrient for almost all living organisms and paradoxically poorly soluble and consequently poorly bioavailable. To get access to this metal, bacteria have developed many different strategies. One of the most common consists of the use of siderophores, small compounds chelating ferric iron with a very high affinity. Many bacteria are able to produce their own siderophores or use those produced by other microorganisms (exosiderophores) in a piracy strategy. Pseudomonas aeruginosa produces two siderophores, pyoverdine and pyochelin and is able to use a large panel of exosiderophores. We investigated the ability of P. aeruginosa to use nocardamine (NOCA) and ferrioxamine B (DFOB) as exosiderophores under iron-limited planktonic growth conditions. Proteomic and RT-qPCR approaches showed an induction of the transcription and expression of the outer membrane transporter FoxA in the presence of NOCA or DFO in the bacterial environment. Expression of the proteins of the heme or pyoverdine and pyochelin dependent iron uptake pathways were not affected in the presence of these two tris-hydroxamate siderophores. 55Fe uptake assays using foxA mutants demonstrated that ferri-NOCA was exclusively transported by FoxA, while ferri-DFO was transported by FoxA and at least one another unidentified transporter. The crystal structure of FoxA in complex with NOCA revealed very similar siderophore binding sites between NOCA and DFO. Iron uptake by hydroxamate exosiderophores in P. aeruginosa cells is discussed in the light of these results.
INSTRUMENT(S): Q Exactive
ORGANISM(S): Pseudomonas Aeruginosa Pao1
SUBMITTER: Lauriane Kuhn
LAB HEAD: Isabelle Schalk
PROVIDER: PXD020868 | Pride | 2021-04-29
REPOSITORIES: pride
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