Rhizoferrin: A complexone type siderophore of the mocorales and entomophthorales (Zygomycetes)

Thieken, Andrea; Winkelmann, G.

doi:10.1111/j.1574-6968.1992.tb05285.x

Cited by 106 publications

(50 citation statements)

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“…Stereochemical variations of siderophores can be regarded as a relatively rare form of defense against siderophore piracy. To our knowledge, the only other known example of siderophore enantiomers is rhizoferrin, which is made as R,R-rhizoferrin by the fungus Rhizopus and other members of the Zygomycetes (Drechsel et al 1992;Thieken and Winkelmann 1992), and as S,S-rhizoferrin by the soil bacterium Ralstonia pickettii (Münzinger et al 1999). Compared with the immense structural variety of pyoverdines made by fluorescent pseudomonads (Meyer 2000;Budzikiewicz 2004), the possibilities of generating diversity through siderophore enantiomers are more limited.…”

Section: Concluding Remarks and Outstanding Questionsmentioning

confidence: 98%

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: Concluding Remarks and Outstanding Questionsmentioning

confidence: 98%

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

2010

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“…44 The molecule is composed of two moles of citrate linked by ornithine. Besides Staphyloferrin A, 44 also staphyloferrin B, 45 vibrioferrin, 46 and rhizoferrin 47 contain citric acid building blocks. Rhizoferrin has been isolated from culture filtrates of Rhizopus and other members of the class of Zygomycetes (Figure 3(c)).…”

Section: Carboxylate-type Siderophoresmentioning

confidence: 99%

Iron Transport: Siderophores

Matzanke

2005

Encyclopedia of Inorganic Chemistry

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Siderophores (from the Greek: iron carrier) are low molecular mass (500–1500 Da) iron chelators that are synthesized in bacteria and fungi under conditions of iron deficiency. Siderophores exhibit extraordinarily high complex formation constants for ferric iron with β‐values ranging from 10 20 to approximately 10 50 . Fe 2+ ‐siderophores are some 20 orders of magnitude less stable than their Fe 3+ counterparts. The d5 electronic configuration of Fe 3+ rules out any crystal field stabilization energy and makes ferric iron complexes relatively labile with respect to isomerization and ligand exchange. Siderophores display a selectivity for iron that is reflected in the corresponding complex stability constants that are higher with Fe 3+ than with Al 3+ , or with bivalent cations like Ca 2+ , Cu 2+ or Zn 2+ . Microorganisms excrete desferrisiderophores in order to scavenge iron from the environment. The competition for iron by siderophores, the mechanisms of siderophore uptake through microbial membranes, and the intracellular pathways of siderophore‐iron utilization strongly depend on thermodynamic, kinetic, and structural features of the ferric iron siderophore complexes. The structural features of siderophores are diverse. The ligating groups contain oxygen atoms of hydroxamate, catecholate, α‐hydroxy carboxylic and salicylic acids, or oxazoline and thiazoline nitrogen. Reduction potentials of ferric siderophore complexes vary between −700 and −150 mV. In particular at the low potential end below −450 mV, special biological strategies of reductive iron removal are required because these potentials are too negative for typical cellular reductases. The coordination and redox chemistry of siderophores is also reflected in the mechanisms of siderophore‐mediated iron uptake in microorganisms. A classic example is the intracellular removal of iron from enterobactin. The permeation of cell walls or bacterial membranes by siderophores is in most microbes a highly specific process requiring an array of up to eight proteins. The advent of modern molecular biology delivered a cornucopia of methods enabling high‐yield production of specific gene products relevant to siderophore synthesis and transport, analyses of structure‐function relationships (employing site directed mutagenesis), and detailed insights into the regulation of the corresponding processes. One siderophore, ferrioxamine B, serves as a detoxifier in iron overload diseases and in the treatment of β‐thalassemia. Siderophores and siderophore analogs also play a role in MRI and are employed as basic models for actinide chelators in order to remove these metals from the environment or from a contaminated body.

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“…Uptake protocols for the fungus A. spinosa were according to Thieken & Winkelmann (1992). Bioassays using M. morganii 13 were performed as described in Thieken and Winkelmann (1993) on agar plates containing either 2,2'-bipyridyl (300 #M) or ethylenediamine-N,N'-bis(2-hydroxy phenylacetic acid (EDDHA) (500/tM) to bind residual iron in the growth medium.…”

Section: Transport and Bioassaysmentioning

confidence: 99%

Specificity and mechanism of rhizoferrin-mediated metal ion uptake

1996

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Rhizoferrin-mediated iron uptake was studied in two different classes of organisms: a rhizoferrin producing fungus, Absidia sTinosa (Zygomycetes), and a ferric rhizoferrin utilizing bacterium, Morganella morganii (Enterobacteriaceae). The uptake of iron rhizoferrin and some of its metal analogs (chromium, rhodium, gallium), was followed and kinetic parameters measured in A. spinosa. These metal ion complexes were taken up in a concentration-and energy-dependent manner indicative of an active transport system. The uptake of the kineticaily inert chromium and rhodium and reductively inert gallium complexes suggests a variation of the so called 'shuttle' mechanism may be operative. The recognition of one geometrical isomer of chromium-rhizoferrin but not another argues for a degree of stereospecificity in the uptake process. A growth promotion plate assay was used to examine metal-rhizoferrin uptake in M. morganii. The results indicate that a number of factors including the nature of the chelating agent (e.g. bipyridyl or EDDHA) used to induce iron deficiency need to be considered before these simple plate assays can be reliably used to indicate the presence or absence of a particular siderophore uptake system.

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Rhizoferrin: A complexone type siderophore of the mocorales and entomophthorales (Zygomycetes)

Cited by 106 publications

References 4 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

Iron Transport: Siderophores

Specificity and mechanism of rhizoferrin-mediated metal ion uptake

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