Thioredoxin‐Like [2<scp>Fe</scp>–2<scp>S</scp>] Ferredoxin

Meyer, Jacques; Andrade, Susana L. A.; Einsle, Oliver

doi:10.1002/0470028637.met225

Cited by 4 publications

(3 citation statements)

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“…This possibility was previously inferred by changes in frxA expression upon fdx removal in strains of H. pylori [35]. Similar suggestions arose from various kinds of data obtained with other small iron-sulfur proteins, such as thioredoxin-like ferredoxins [39] and the [2Fe-2S] isc -associated Fdx of E. coli in the secretion of cytotoxic necrotizing factor 1 [40]. Potential regulating mechanisms involving Fdx cannot be discussed at this stage, but they may include stabilization of proteins or protein complexes, electron exchange with redox-sensitive regulators, and others.…”

Section: Discussionsupporting

confidence: 71%

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

et al. 2010

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BackgroundFerredoxins are small iron-sulfur proteins belonging to all domains of life. A sub-group binds two [4Fe-4S] clusters with unequal and extremely low values of the reduction potentials. These unusual properties are associated with two specific fragments of sequence. The functional importance of the very low potential ferredoxins is unknown.ResultsA bioinformatic screening of the sequence features defining very low potential 2[4Fe-4S] ferredoxins has revealed the almost exclusive presence of the corresponding fdx gene in the Proteobacteria phylum, without occurrence in Archaea and Eukaryota. The transcript was found to be monocistronic in Pseudomonas aeruginosa, and not part of an operon in most bacteria. Only fdx genes of bacteria which anaerobically degrade aromatic compounds belong to operons. As this pathway is not present in all bacteria having very low potential 2[4Fe-4S] ferredoxins, these proteins cannot exclusively be reductants of benzoyl CoA reductases. Expression of the ferredoxin gene did not change in response to varying growth conditions, including upon macrophage infection or aerobic growth with 4-hydroxy benzoate as carbon source. However, it increased along the growth curve in Pseudomonas aeruginosa and in Escherichia coli. The sequence immediately 5' upstream of the coding sequence contributed to the promotor activity. Deleting the fdx gene in Pseudomonas aeruginosa abolished growth, unless a plasmid copy of the gene was provided to the deleted strain.ConclusionsThe gene of the very low potential 2[4Fe-4S] ferredoxin displays characteristics of a housekeeping gene, and it belongs to the minority of genes that are essential in Pseudomonas aeruginosa. These data identify a new potential antimicrobial target in this and other pathogenic Proteobacteria.

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Section: Discussionsupporting

confidence: 71%

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

et al. 2010

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“…Structural data are not available for Clostridium pasteurianum [Fe 2 S 2 ] ferredoxin, which is a member of the thioredoxin-like class of ferredoxins . However, high resolution crystal structures are available for the oxidized form of a close homolog of the Cp Fd, the wild-type (WT) [Fe 2 S 2 ] ferredoxin-4 from the hyperthermophilic bacterium Aquifex aeolicus ( Aae Fd4) (solved at 1.5 Å resolution), and the corresponding oxidized Cys-to-Ser variants, C55S and C59S (solved at 1.25 Å and 1.05 Å resolution, respectively). , The crystallographic data indicated a thioredoxin-like fold and confirmed serinate ligation to the oxidized [Fe 2 S 2 ] 2+ cluster in both variants.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic and Redox Studies of Valence-Delocalized [Fe₂S₂]⁺ Centers in Thioredoxin-like Ferredoxins

et al. 2015

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Reduced forms of the C56S and C60S variants of the thioredoxin-like Clostridium pasteurianum [Fe2S2] ferredoxin (CpFd) provide the only known examples of valence-delocalized [Fe2S2]+ clusters, which constitute a fundamental building block of all higher nuclearity Fe-S clusters. In this work, we have revisited earlier work on the CpFd variants and carried out redox and spectroscopic studies on the [Fe2S2]2+,+ centers in wild-type and equivalent variants of the highly homologous and structurally characterized Aquifex aeolicus ferredoxin 4 (AaeFd4) using EPR, UV-visible-NIR absorption, CD and variable-temperature MCD, and protein-film electrochemistry. The results indicate that the [Fe2S2]+ centers in the equivalent AaeFd4 and CpFd variants reversibly interconvert between similar valence-localized S = 1/2 and valence-delocalized S = 9/2 forms as a function of pH, with pKa values in the range 8.3-9.0, due to protonation of the coordinated serinate residue. However, freezing high-pH samples results in partial or full conversion from valence-delocalized S = 9/2 to valence-localized S = 1/2 [Fe2S2]+ clusters. MCD saturation magnetization data for valence-delocalized S = 9/2 [Fe2S2]+ centers facilitated determination of transition polarizations and thereby assignments of low-energy MCD bands associated with the Fe−Fe interaction. The assignments provide experimental assessment of the double exchange parameter, B, for valence-delocalized [Fe2S2]+ centers and demonstrate that variable-temperature MCD spectroscopy provides a means of detecting and investigating the properties of valence-delocalized S = 9/2 [Fe2S2]+ fragments in higher nuclearity Fe-S clusters. The origin of valence delocalization in thioredoxin-like ferredoxin Cys-to-Ser variants and Fe-S clusters in general is discussed in light of these results.

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“…Two of these, nuoE2 from pSymA and Smed-3619 from pSMED01 are predicted to be members of the NADH:ubiquinone oxidoreductase family (Nuo)/ Thioredoxin-like [2Fe–2S] Ferredoxin family of proteins. The Thioredoxin-like [2Fe–2S] ferredoxin family is characterized by a four cysteine cluster organized in an approximate C-X 10 -C-X 29 -C-X 3 -C motif that functions in binding of an iron-sulfur cluster (Meyer 2011). Further inspection of the nuoE2 and Smed-3619 sequences, which are 91% identical, reveals that the identified C-X-X-C motif is due to the presence of a fifth cysteine within this conserved four cysteine cluster, resulting in a C-X 4 -[C-X 2 -C]-X 32 -C-X 3 -C motif in both nuoE2 and Smed-3619.…”

Section: Phylogenetic Analysis Of Trx-like Proteinsmentioning

confidence: 99%

Thioredoxin-like proteins in F and other plasmid systems

Hemmis

Schildbach

2013

Plasmid

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Bacterial conjugation is the process by which a conjugative plasmid transfers from donor to recipient bacterium. During this process, single-stranded plasmid DNA is actively and specifically transported from the cytoplasm of the donor, through a large membrane-spanning assembly known as the pore complex, and into the cytoplasm of the recipient. In Gram negative bacteria, construction of the pore requires localization of a subset of structural and catalytically active proteins to the bacterial periplasm. Unlike the cytoplasm, the periplasm contains proteins that promote disulfide bond formation within or between cysteine-containing proteins. To ensure proper protein folding and assembly, bacteria employ periplasmic redox systems for thiol oxidation, disulfide bond/sulfenic acid reduction, and disulfide bond isomerization. Recent data suggest that plasmid-based proteins belonging to the disulfide bond formation family play an integral role in the conjugative process by serving as mediators in folding and/or assembly of pore complex proteins. Here we report the identification of 165 thioredoxin-like family members across 89 different plasmid systems. Using phylogenetic analysis, all but nine family members were categorized into thioredoxin-like subfamilies. In addition, we discuss the diversity, conservation, and putative roles of thioredoxin-like proteins in plasmid systems, which include homologs of DsbA, DsbB, DsbC, DsbD, DsbG, and CcmG from Escherichia coli, TlpA from Bradyrhizobium japonicum, Com1 from Coxiella burnetii, as well as TrbB and TraF from plasmid F, and the absolute conservation of a disulfide isomerase in plasmids containing homologs of the transfer proteins TraH, TraN, and TraU.

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Thioredoxin‐Like [2Fe–2S] Ferredoxin

Cited by 4 publications

References 100 publications

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

Spectroscopic and Redox Studies of Valence-Delocalized [Fe₂S₂]⁺ Centers in Thioredoxin-like Ferredoxins

Thioredoxin-like proteins in F and other plasmid systems

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Thioredoxin‐Like [2Fe–2S] Ferredoxin

Cited by 4 publications

References 100 publications

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

A bacteria-specific 2[4Fe-4S] ferredoxin is essential in Pseudomonas aeruginosa

Spectroscopic and Redox Studies of Valence-Delocalized [Fe2S2]+ Centers in Thioredoxin-like Ferredoxins

Thioredoxin-like proteins in F and other plasmid systems

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Spectroscopic and Redox Studies of Valence-Delocalized [Fe₂S₂]⁺ Centers in Thioredoxin-like Ferredoxins