Functions of the siderophore esterases IroD and IroE in iron-salmochelin utilization
| Autor: | Marianne Valdebenito, Klaus Hantke, Günther Winkelmann, Mingang Zhu |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Siderophore
animal structures Binding protein Mutant Esterases Siderophores ATP-binding cassette transporter Periplasmic space Biology medicine.disease_cause Ferric Compounds Microbiology chemistry.chemical_compound Enterobactin chemistry Biochemistry Genes Bacterial Salmonella Gene cluster Escherichia coli medicine |
| Zdroj: | Microbiology. 151:2363-2372 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/mic.0.27888-0 |
| Popis: | The siderophore salmochelin is produced under iron-poor conditions bySalmonellaand many uropathogenicEscherichia colistrains. The production of salmochelin, a C-glucosylated enterobactin, is dependent on the synthesis of enterobactin and theiroBCDENgene cluster. AnE. coliIroD protein with an N-terminal His-tag cleaved cyclic salmochelin S4 to the linear trimer salmochelin S2, the dimer salmochelin S1, and the monomers dihydroxybenzoylserine and C-glucosylated dihydroxybenzoylserine (salmochelin SX, pacifarinic acid). The periplasmic IroE protein was purified as a MalE–IroE fusion protein. This enzyme degraded salmochelin S4 and ferric-salmochelin S4 to salmochelin S2 and ferric-salmochelin S2, respectively. InE. coli, uptake of ferric-salmochelin S4 was dependent on the cleavage by IroE, and independent of the FepBDGC ABC transporter in the cytoplasmic membrane. IroC, which has similarities to ABC-multidrug-resistance proteins, was necessary for the uptake of salmochelin S2 from the periplasm into the cytoplasm. IroE did not function as a classical binding protein since salmochelin S2 was taken up in the absence of a functional IroE protein. IroC mediated the uptake of iron via enterobactin in afepBmutant. IroE was also necessary in this case for the uptake of ferric-enterobactin, which indicated that only the linear degradation products of enterobactin were taken up via IroC. PfeE, thePseudomonas aeruginosaIroE homologue, was cloned, and its enzymic activity was shown to be very similar to that of IroE. It is suggested that homologues in other bacteria are also periplasmic IroE-type esterases of siderophores. |
| Databáze: | OpenAIRE |
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