Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor.
AUTOR(ES)
Gilis, A
RESUMO
Siderophore production in response to iron limitation was observed in Alcaligenes eutrophus CH34, and the corresponding siderophore was named alcaligin E. Alcaligin E was characterized as a phenolate-type siderophore containing neither catecholate nor hydroxamate groups. Alcaligin E promoted the growth of siderophore-deficient A. eutrophus mutants under iron-restricted conditions and promoted 59Fe uptake by iron-limited cells. However, the growth of the Sid- mutant AE1152, which was obtained from CH34 by Tn5-Tc mutagenesis, was completely inhibited by the addition of alcaligin E. AE1152 also showed strongly reduced 59Fe uptake in the presence of alcaligin E. This indicates that a gene, designated aleB, which is involved in transport of ferric iron-alcaligin E across the membrane is inactivated. The aleB gene was cloned, and its putative amino acid sequence showed strong similarity to those of ferric iron-siderophore receptor proteins. Both wild-type strain CH34 and aleB mutant AE1152 were able to use the same heterologous siderophores, indicating that AleB is involved only in ferric iron-alcaligin E uptake. Interestingly, no utilization of pyochelin, which is also a phenolate-type siderophore, was observed for A. eutrophus CH34. Genetic studies of different Sid- mutants, obtained after transposon mutagenesis, showed that the genes involved in alcaligin E and ferric iron-alcaligin E receptor biosynthesis are clustered in a 20-kb region on the A. eutrophus CH34 chromosome in the proximity of the cys-232 locus.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=178374Documentos Relacionados
- Essential Role of the Iron-Regulated Outer Membrane Receptor FauA in Alcaligin Siderophore-Mediated Iron Uptake in Bordetella Species
- Siderophore-mediated uptake of iron in Azotobacter vinelandii.
- Characterization of Fluorescent Siderophore-Mediated Iron Uptake in Pseudomonas sp. Strain M114: Evidence for the Existence of an Additional Ferric Siderophore Receptor
- Siderophore-mediated iron uptake in different strains of Anabaena sp.
- Siderophore-Mediated Iron Sequestering by Shewanella putrefaciens