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Münzinger, Maik; Taraz, K.; Budzikiewicz, H.; Drechsel, Hartmut; Heymann, Petra; Winkelmann, G.; Meyer, Jean‐Marie

doi:10.1023/a:1009259118034

Cited by 44 publications

(27 citation statements)

References 17 publications

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“…Stereospecificity of iron uptake systems has been observed previously with several other siderophores such as parabactin, rhodotorulic acid, ferrichrome, and enterobactin and their corresponding enantiomers (45)(46)(47)(48)(49)(50)(51)(52). However, so far no siderophore outer membrane transporters have been described with opposite binding enantioselectivities.…”

Section: Discussionmentioning

confidence: 69%

Stereospecificity of the Siderophore Pyochelin Outer Membrane Transporters in Fluorescent Pseudomonads

Hoegy

Lee

Noël

et al. 2009

Journal of Biological Chemistry

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Pyochelin (Pch) and enantio-pyochelin (EPch) are enantiomer siderophores that are produced by Pseudomonas aeruginosa and Pseudomonas fluorescens, respectively, under iron limitation. Pch promotes growth of P. aeruginosa when iron is scarce, and EPch carries out the same biological function in P. fluorescens. However, the two siderophores are unable to promote growth in the heterologous species, indicating that siderophore-mediated iron uptake is highly stereospecific. In the present work, using binding and iron uptake assays, we found that FptA, the Fe-Pch outer membrane transporter of P. aeruginosa, recognized (K d ‫؍‬ 2.5 ؎ 1.1 nM) and transported Fe-Pch but did not interact with Fe-EPch. Likewise, FetA, the Fe-EPch receptor of P. fluorescens, was specific for Fe-EPch (K d ‫؍‬ 3.7 ؎ 2.1 nM) but did not bind and transport Fe-Pch. Growth promotion experiments performed under iron-limiting conditions confirmed that FptA and FetA are highly specific for Pch and EPch, respectively. When fptA and fetA along with adjacent transport genes involved in siderophore uptake were swapped between the two bacterial species, P. aeruginosa became able to utilize Fe-EPch as an iron source, and P. fluorescens was able to grow with Fe-Pch. Docking experiments using the FptA structure and binding assays showed that the stereospecificity of Pch recognition by FptA was mostly due to the configuration of the siderophore chiral centers C4؆ and C2؆ and was only weakly dependent on the configuration of the C4 carbon atom. Together, these findings increase our understanding of the stereospecific interaction between Pch and its outer membrane receptor FptA.To access iron, aerobic bacteria produce siderophores which form complexes with Fe 3ϩ in the environment and deliver it via specific membrane transporters to the bacteria (1). The energy required for this process is provided by the proton motive force of the inner membrane by means of an inner membrane complex comprising TonB, ExbB, and ExbD (2, 3). Pyochelin (Pch), 2 which is the focus of this study, is produced as a secondary siderophore under iron limitation by almost all strains of Pseudomonas aeruginosa and some closely related bacteria (4 -7). In pseudomonads, secondary siderophores (pyochelin, thioquinolobactin, etc.) are usually produced in smaller amounts, demonstrate lower iron affinity, and are rather simple molecules compared with pyoverdin (the main siderophore). It is hypothesized that under certain environmental or physiological conditions, secondary siderophores provide sufficient iron to the cell or fulfill functions other than iron sequestration (8). Pch was isolated for the first time from P. aeruginosa ATCC 15692 by Liu and Shokrani (9), and its structure was established later by Cox et al. (10) as (4ЈR,2ЉR,4ЉR)-2Ј-(2-hydroxyphenyl)-3Љ-methyl-4Ј,5Ј,2Љ,3Љ,4Љ,5Љ-hexahydro-[4Ј,2Љ]bithiazolyl-4Љ-carboxylic acid with three chiral centers located at C4Ј, C2Љ, and C4Љ (see Fig. 1). Pch is synthesized by P. aeruginosa from salicylate and two molecules of cysteine via a thiot...

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Section: Discussionmentioning

confidence: 69%

Stereospecificity of the Siderophore Pyochelin Outer Membrane Transporters in Fluorescent Pseudomonads

Hoegy

Lee

Noël

et al. 2009

Journal of Biological Chemistry

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“…[65], production of siderophores by Ralstonia [66] and formation of biofilm on the surfaces of minerals (e.g. Acidovorax).…”

Section: Discussionmentioning

confidence: 99%

Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

López-Fernández

Cherkouk²,

Vílchez-Vargas

et al. 2015

Microb Ecol

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The long-term disposal of radioactive wastes in a deep geological repository is the accepted international solution for the treatment and management of these special residues. The microbial community of the selected host rocks and engineered barriers for the deep geological repository may affect the performance and the safety of the radioactive waste disposal. In this work the bacterial population of bentonite formations of Almeria (Spain), selected as reference material for bentonite engineered barriers in the disposal of radioactive wastes, was studied. 16S rRNA gene-based approaches were used to study the bacterial community of the bentonite samples by traditional clone libraries and Illumina-sequencing. By both techniques the bacterial diversity analysis revealed similar results, with phylotypes belonging to 14 different bacterial phyla:

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“…(27,30). More recently, rhizoferrin has been shown to be produced by the bacteria Francisella tularensis and Ralstonia pickettii (28,29). Interestingly, LbtA shares 33% amino acid identity and 52% amino acid similarity with the FslA/FigA protein that is required for siderophore production by F. tularensis (28,43).…”

Section: Discussionmentioning

confidence: 99%

“…3). Based on these NMR results, combined with the MS data, legiobactin was determined to have a structure identical to that of rhizoferrin (27,29).…”

Section: Fig 4 1d Nmr Analysis Of Purified Legiobactin Hplc-purifiedmentioning

confidence: 99%

The Legionella pneumophila Siderophore Legiobactin Is a Polycarboxylate That Is Identical in Structure to Rhizoferrin

Burnside

Shafaie

et al. 2015

Infect Immun

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bLegionella pneumophila, the agent of Legionnaires' disease, secretes a siderophore (legiobactin) that promotes bacterial infection of the lung. In past work, we determined that cytoplasmic LbtA (from Legiobactin gene A) promotes synthesis of legiobactin, inner membrane LbtB aids in export of the siderophore, and outer membrane LbtU and inner membrane LbtC help mediate ferrilegiobactin uptake and assimilation. However, the past studies examined legiobactin contained within bacterial culture supernatants. By utilizing high-pressure liquid chromatography that incorporates hydrophilic interaction-based chemistry, we have now purified legiobactin from supernatants of virulent strain 130b that is suitable for detailed chemical analysis. High-resolution mass spectrometry (MS) revealed that the molecular mass of (protonated) legiobactin is 437.140 Da. On the basis of the results obtained from both MS analysis and various forms of nuclear magnetic resonance, we found that legiobactin is composed of two citric acid residues linked by a putrescine bridge and thus is identical in structure to rhizoferrin, a polycarboxylate-type siderophore made by many fungi and several unrelated bacteria. Both purified legiobactin and rhizoferrin obtained from the fungus Cunninghamella elegans were able to promote Fe 3؉ uptake by wild-type L. pneumophila as well as enhance growth of iron-starved bacteria. These results did not occur with 130b mutants lacking lbtU or lbtC, indicating that both endogenously made legiobactin and exogenously derived rhizoferrin are assimilated by L. pneumophila in an LbtU-and LbtC-dependent manner.T he Gram-negative bacterium Legionella pneumophila is both an inhabitant of natural and man-made water systems and the primary etiologic agent of Legionnaires' disease, an increasingly common and serious form of pneumonia (1-3). In its aquatic habitats, L. pneumophila survives in biofilms and as an intracellular parasite of amoebae, and in the lung, it grows primarily in macrophages (4-7). Iron has long been recognized as a major aspect of L. pneumophila replication, intracellular infection, and virulence (8, 9). For ferrous iron assimilation, L. pneumophila utilizes a secreted pyomelanin that has ferric reductase activity and the inner membrane Fe 2ϩ transporter FeoB (10, 11). For ferric iron uptake, the bacterium uses the siderophore legiobactin (12, 13). Both of these iron acquisition pathways are required for infection of the lungs by L. pneumophila (10,14).The investigation of legiobactin has followed a rather circuitous path. Indeed, it was originally thought that L. pneumophila does not produce siderophores; this conclusion was based on negative data obtained from both the Arnow and Csáky assays, which detect catecholate and hydroxymate structures, respectively, and the Chrome Azurol S (CAS) assay, which detects iron chelators independently of their structure (15-17). However, in 2000, we demonstrated that L. pneumophila strains can secrete a siderophore activity that is detected by the CAS assay when the ba...

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Cited by 44 publications

References 17 publications

Stereospecificity of the Siderophore Pyochelin Outer Membrane Transporters in Fluorescent Pseudomonads

Stereospecificity of the Siderophore Pyochelin Outer Membrane Transporters in Fluorescent Pseudomonads

Bacterial Diversity in Bentonites, Engineered Barrier for Deep Geological Disposal of Radioactive Wastes

The Legionella pneumophila Siderophore Legiobactin Is a Polycarboxylate That Is Identical in Structure to Rhizoferrin

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