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Siderophore specifities of ChtA and ActA, two TonB-dependent transporters of Pseudomonas

ABSTRACT: Iron is an essential nutrient for the opportunistic pathogen Pseudomonas aeruginosa, as for almost all living organisms. To access this element, the pathogen is able to express at least 15 different iron-uptake pathways, the vast majority involving small iron chelators called siderophores. Indeed, P. aeruginosa produces two siderophores, pyoverdine and pyochelin, but can also use many produced by other microorganisms. This implies that the bacterium expresses appropriate TonB-dependent transporters (TBDTs) at the outer membrane to import the ferric form of each of the siderophores used. These transporters are highly selective for a given ferri-siderophore complex or for siderophores with similar chemical structures. Here, we show that P. aeruginosa can also use rhizoferrin, staphyloferrin A, aerobactin, and schizokinen as siderophores to access iron. Growth assays in iron-restricted conditions and 55Fe uptake assays showed that the two alpha-carboxylate type siderophores rhizoferrin-Fe and staphyloferrin A-Fe are transported into P. aeruginosa cells by the TBDT ActA (PA3268). Among the mixed alpha-carboxylate/hydroxamate type siderophores, we found aerobactin-Fe to be transported by ChtA (as previously described) and schizokinen-Fe by ChtA and another unidentified TBDT.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Pseudomonas Aeruginosa Pao1

SUBMITTER: Lauriane Kuhn

LAB HEAD: Isabelle Schalk

PROVIDER: PXD043056 | Pride | 2023-09-21

REPOSITORIES: Pride

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