Stereospecific recognition of pyochelin and enantio-pyochelin by the PchR proteins in fluorescent pseudomonads

Youard, Zeb A.; Reimmann, Cornelia

doi:10.1099/mic.0.037796-0

Cited by 16 publications

(19 citation statements)

References 41 publications

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“…Iron uptake and signalling with E-Pch in P. fluorescens (b) is expected to proceed in a similar way, except that after FetA-dependent transport through the outer membrane, the iron-siderophore complex may cross the inner membrane via a classical ABC transport system encoded by genes of the fetABCDEF operon. Note that in the absence of FptA and FetA, respectively, activation of PchR by its cognate siderophore is reduced but not abolished (Youard and Reimmann 2010), implying that the siderophores can enter the cells also by an alternative, lowefficiency uptake pathway. Under iron-replete conditions, the Fur repressor blocks transcription of pchDCBA, pchR, pchEFGHI, and fptABCX in P. aeruginosa, and a similar repression of pchDHIEFKCBA, pchR, and fetABCDEF probably occurs in P. fluorescens (see text) Biometals (2011) 24:513-522 517 1994; Fig.…”

Section: Iron Uptakementioning

confidence: 97%

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

2010

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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.

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Section: Iron Uptakementioning

confidence: 97%

“…Interestingly, Pch and E-Pch are biologically active only in their producer species (Youard et al 2007;Hoegy et al 2009;Youard and Reimmann 2010), suggesting that iron uptake with these compounds is highly stereospecific.…”

Section: Introductionmentioning

confidence: 97%

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

2010

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“…All gene replacement mutants of P. aeruginosa and P. fluorescens listed in Table 1 were generated with suicide plasmids as described previously (Schnider et al, 1995;Ye et al, 1995;Laville et al, 1998). Apart from pME7152 (Michel et al, 2007), pME9253 (Youard & Reimmann, 2010) and pME9605 (Brillet et al, 2011), all new suicide plasmids were constructed in a similar way. First, two PCR fragments were generated from chromosomal DNA using primer pairs 1/2 and 3/4 (see Table S1 for nucleotide sequences).…”

Section: Methodsmentioning

confidence: 99%

“…Genetic, biochemical and structural data have so far revealed that stereospecificity of siderophore recognition occurs (i) at the outer membrane, by the receptors FptA and FetA (Hoegy et al, 2009;Brillet et al, 2011), and (ii) in the cytoplasm, by the two different versions of the regulatory proteins PchR, each of which is activated by its cognate siderophore only (Youard & Reimmann, 2010). The question of whether siderophore chirality is also important during transport across the inner membrane has not been addressed so far, mainly because the respective genes for ferriEPch transport in P. fluorescens have not been studied experimentally.…”

Section: Introductionmentioning

confidence: 99%

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Inner-membrane transporters for the siderophores pyochelin in Pseudomonas aeruginosa and enantio-pyochelin in Pseudomonas fluorescens display different enantioselectivities

Reimmann

2012

Microbiology

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Iron uptake and transcriptional regulation by the enantiomeric siderophores pyochelin (Pch) and enantio-pyochelin (EPch) of Pseudomonas aeruginosa and Pseudomonas fluorescens, respectively, are stereospecific processes. The iron-loaded forms of Pch (ferriPch) and of EPch (ferriEPch) are recognized stereospecifically (i) at the outer membrane by the siderophore receptors FptA in P. aeruginosa and FetA in P. fluorescens and (ii) in the cytoplasm by the two AraC-type regulators PchR, which are activated by their cognate siderophore. Here, stereospecific siderophore recognition is shown to occur at the inner membrane also. In P. aeruginosa, translocation of ferriPch across the inner membrane is carried out by the singlesubunit siderophore transporter FptX. In contrast, the uptake of ferriEPch into the cytoplasm of P. fluorescens was found to involve a classical periplasmic binding protein-dependent ABC transporter (FetCDE), which is encoded by the fetABCDEF operon. Expression of a translational fetA-gfp fusion was repressed by ferric ions, and activated by the cognate siderophore bound to PchR, thus resembling the analogous regulation of the P. aeruginosa ferriPch transport operon fptABCX. The inner-membrane transporters FetCDE and FptX were expressed in combination with either of the two siderophore receptors FetA and FptA in a siderophore-negative P. aeruginosa mutant deleted for the fptABCX operon. Growth tests conducted under iron limitation with ferriPch or ferriEPch as the iron source revealed that FptX was able to transport ferriPch as well as ferriEPch, whereas FetCDE specifically transported ferriEPch. Thus, stereospecific siderophore recognition occurs at the inner membrane by the FetCDE transporter.

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Microbial siderophores: a mini review

et al. 2012

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Iron is one of the major limiting factors and essential nutrients of microbial life. Since in nature it is not readily available in the preferred form, microorganisms produce small high affinity chelating molecules called siderophores for its acquisition. Microorganisms produce a wide variety of siderophores controlled at the molecular level by different genes to accumulate, mobilize and transport iron for metabolism. Siderophores also play a critical role in the expression of virulence and development of biofilms by different microbes. Apart from maintaining microbial life, siderophores can be harnessed for the sustainability of human, animals and plants. With the advent of modern molecular tools, a major breakthrough is taking place in the understanding of the multifaceted role of siderophores in nature. This mini review is intended to provide a general overview on siderophore along with its role and applications.

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Stereospecific recognition of pyochelin and enantio-pyochelin by the PchR proteins in fluorescent pseudomonads

Cited by 16 publications

References 41 publications

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

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

Inner-membrane transporters for the siderophores pyochelin in Pseudomonas aeruginosa and enantio-pyochelin in Pseudomonas fluorescens display different enantioselectivities

Microbial siderophores: a mini review

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