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Iron acquisition with the natural siderophore enantiomers pyochelin and enantio-pyochelin in Pseudomonas species

Type of publication Peer-reviewed
Publikationsform Review article (peer-reviewed)
Publication date 2011
Author Youard Zeb A, Wenner Nicolas, Reimmann Cornelia,
Project Enantio-pyochelin: Biosynthesis, regulation, and natural occurrence
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Review article (peer-reviewed)

Journal Biometals
Volume (Issue) 24(3)
Page(s) 513 - 522
Title of proceedings Biometals
DOI 10.1007/s10534-010-9399-9

Open Access


The bacterial siderophore pyochelin is composed of salicylate and two cysteine-derived heterocycles, the second of which is modified by reduction and N-methylation during biosynthesis. In Pseudomonas aeruginosa, the first cysteine residue is converted to its D-isoform during thiazoline ring formation, whereas the second cysteine remains in its L-configuration. Stereochemistry is opposite in the Pseudomonas fluorescens siderophore enantio-pyochelin, in which the first ring originates from L-cysteine and the second ring from D-cysteine. Both siderophores promote growth of the producer organism during iron limitation and induce the expression of their biosynthesis genes by activating the transcriptional AraC-type regulator PchR. However, neither siderophore is functional as an iron carrier or as a transcriptional inducer in the other species, demonstrating that both processes are highly stereospecific. Stereospecificity of pyochelin/enantio-pyochelin-mediated iron uptake is ensured at two levels: (i) by the outer membrane siderophore receptors and (ii) by the cytosolic PchR regulators.