Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor.

Abstract

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.

• Authors: A Gilis, M A Khan, P Cornelis, J M Meyer, M Mergeay, D van der Lelie
• Journal: Journal of bacteriology (J Bacteriol) Vol. 178 Issue 18 Pg. 5499-507 (Sep 1996) ISSN: 0021-9193 [Print] United States
• PMID: 8808942 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Ferric Compounds
• Hydroxamic Acids
• Phenols
• Receptors, Cell Surface
• Siderophores
• alcaligin
• ferric iron-alcaligin E receptor, Ralstonia eutropha
• alcaligin E
• Iron

Topics

• Alcaligenes (classification, genetics, metabolism)
• Amino Acid Sequence
• Bacterial Proteins
• Biological Transport
• Chromosome Mapping
• Cloning, Molecular
• Ferric Compounds (metabolism)
• Genes, Bacterial
• Genetic Complementation Test
• Hydroxamic Acids
• Iron (metabolism)
• Molecular Sequence Data
• Mutagenesis, Insertional
• Mutation
• Phenols
• Receptors, Cell Surface (genetics)
• Sequence Analysis, DNA
• Sequence Homology, Amino Acid
• Siderophores (classification, metabolism)