This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Drechsel, H Articles by Winkelmann, G Search for Related Content PubMed PubMed Citation Articles by Drechsel, H Articles by Winkelmann, G

 Previous Article  |  Next Article 

J Bacteriol. 1993 May; 175(9): 2727-2733

research-article

Alpha-keto acids are novel siderophores in the genera Proteus, Providencia, and Morganella and are produced by amino acid deaminases.

H Drechsel, A Thieken, R Reissbrodt, G Jung and G Winkelmann

Institut für Organische Chemie, Universität Tübingen, Germany.

ABSTRACT

Growth promotion and iron transport studies revealed that certain alpha-keto acids generated by amino acid deaminases, by enterobacteria of the Proteus-Providencia-Morganella group (of the tribe Proteeae), show significant siderophore activity. Their iron-binding properties were confirmed by the chrome azurol S assay and UV spectra. These compounds form ligand-to-metal charge transfer bands in the range of 400 to 500 nm. Additional absorption bands of the enolized ligands at 500 to 700 nm are responsible for color formation. Siderophore activity was most pronounced with alpha-keto acids possessing an aromatic or heteroaromatic side chain, like phenylpyruvic acid and indolylpyruvic acid, resulting from deamination of phenylalanine and tryptophan, respectively. In addition, alpha-keto acids possessing longer nonpolar side chains, like alpha-ketoisocaproic acid or alpha-ketoisovaleric acid and even alpha-ketoadipic acid, also showed siderophore activity which was absent or negligible with smaller alpha-keto acids or those possessing polar functional groups, like pyruvic acid, alpha-ketobutyric acid, or alpha-ketoglutaric acid. The fact that deaminase-negative enterobacteria, like Escherichia coli and Salmonella spp., could not utilize alpha-keto acids supports the view that specific iron-carboxylate transport systems have evolved in members of the tribe Proteeae and are designed to recognize ferric complexes of both alpha-hydroxy acids and alpha-keto acids, of which the latter can easily be generated by L-amino acid deaminases in an amino acid-rich medium. Exogenous siderophores, like ferric hydroxamates (ferrichromes) and ferric polycarboxylates (rhizoferrin and citrate), were also utilized by members of the tribe Proteeae.

---

J Bacteriol. 1993 May; 175(9): 2727-2733

This article has been cited by other articles:

• Jacobsen, S. M., Stickler, D. J., Mobley, H. L. T., Shirtliff, M. E. (2008). Complicated Catheter-Associated Urinary Tract Infections Due to Escherichia coli and Proteus mirabilis. Clin. Microbiol. Rev. 21: 26-59 [Abstract] [Full Text]  
• Kuroda, M., Yamashita, A., Hirakawa, H., Kumano, M., Morikawa, K., Higashide, M., Maruyama, A., Inose, Y., Matoba, K., Toh, H., Kuhara, S., Hattori, M., Ohta, T. (2005). Whole genome sequence of Staphylococcus saprophyticus reveals the pathogenesis of uncomplicated urinary tract infection. Proc. Natl. Acad. Sci. USA 102: 13272-13277 [Abstract] [Full Text]  
• Skovran, E., Downs, D. M. (2000). Metabolic Defects Caused by Mutations in the isc Gene Cluster in Salmonella enterica Serovar Typhimurium: Implications for Thiamine Synthesis. J. Bacteriol. 182: 3896-3903 [Abstract] [Full Text]  
• Liles, M. R., Scheel, T. A., Cianciotto, N. P. (2000). Discovery of a Nonclassical Siderophore, Legiobactin, Produced by Strains of Legionella pneumophila. J. Bacteriol. 182: 749-757 [Abstract] [Full Text]  
• Howard, D. H. (1999). Acquisition, Transport, and Storage of Iron by Pathogenic Fungi. Clin. Microbiol. Rev. 12: 394-404 [Abstract] [Full Text]  
• Kunz, D. A., Chen, J.-L., Pan, G. (1998). Accumulation of alpha -Keto Acids as Essential Components in Cyanide Assimilation by Pseudomonas fluorescens NCIMB 11764. Appl. Environ. Microbiol. 64: 4452-4459 [Abstract] [Full Text]