The dinuclear iron‐oxo ferroxidase center of <i>Pyrococcus furiosus</i> ferritin is a stable prosthetic group with unexpectedly high reduction potentials

Tatur, Jana; Hagen, Wilfred R.

doi:10.1016/j.febslet.2005.07.045

Cited by 24 publications

(25 citation statements)

References 22 publications

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“…The PfFtn FC followed the common trend, and as mentioned already the occupation of FC sites B and C was only observed in Fe-soaked or Zn-soaked crystals. This contradicted our EPR studies that showed a fully developed dinuclear iron FC EPR signal in the sample prior to crystallization [39]. In order to check the integrity of the PfFtn FC, we loaded three samples of apo PfFtn with iron and incubated them for 1 day and 2 months at 4 °C in air and, mimicking the crystallization conditions, for 2 months in a 2 M ammonium sulfate solution at room temperature.…”

Section: Resultsmentioning

confidence: 65%

Crystal structure of the ferritin from the hyperthermophilic archaeal anaerobe Pyrococcus furiosus

2007

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The crystal structure of the ferritin from the archaeon, hyperthermophile and anaerobe Pyrococcus furiosus (PfFtn) is presented. While many ferritin structures from bacteria to mammals have been reported, until now only one was available from archaea, the ferritin from Archaeoglobus fulgidus (AfFtn). The PfFtn 24-mer exhibits the 432 point-group symmetry that is characteristic of most ferritins, which suggests that the 23 symmetry found in the previously reported AfFtn is not a common feature of archaeal ferritins. Consequently, the four large pores that were found in AfFtn are not present in PfFtn. The structure has been solved by molecular replacement and refined at 2.75-Å resolution to R = 0.195 and R free = 0.247. The ferroxidase center of the aerobically crystallized ferritin contains one iron at site A and shows sites B and C only upon iron or zinc soaking. Electron paramagnetic resonance studies suggest this iron depletion of the native ferroxidase center to be a result of a complexation of iron by the crystallization salt. The extreme thermostability of PfFtn is compared with that of eight structurally similar ferritins and is proposed to originate mostly from the observed high number of intrasubunit hydrogen bonds. A preservation of the monomer fold, rather than the 24-mer assembly, appears to be the most important factor that protects the ferritin from inactivation by heat.

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Section: Resultsmentioning

confidence: 65%

Crystal structure of the ferritin from the hyperthermophilic archaeal anaerobe Pyrococcus furiosus

2007

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“…the invariant metallic motive constituted by iron atoms bridged by a peroxo group, which are permanently bound to specific amino acids of the protein, is a stable prosthetic group and that after formation of a stable diiron center, iron(II) is oxidized on its way to the core by the iron(III) in the ferroxidase center, and electrons are transferred to O2 [57]. EPR [58] and kinetic studies [59] support this assumption.…”

Section: Ferritin Iron Uptakementioning

confidence: 58%

Ferritin iron uptake and release in the presence of metals and metalloproteins: Chemical implications in the brain

Carmona

Palacios

Gálvez

et al. 2013

Coordination Chemistry Reviews

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Living organisms have developed a chemical machinery based on the ferritin protein for the storage, under a nontoxic form, of the iron that is not required for immediate metabolic purposes. Whereas free iron causes extensive cell damage, ferritin iron is not toxic, yet still available for cell requirements. However, iron storage in ferritin is increasingly being recognized as a crucial process related with some neurodegenerative disorders and therefore, an understanding of the management of iron in the brain, especially the processes of iron uptake and release in ferritin, is compulsory to clarify the role of this metalloprotein in these neuropathologies.Although knowledge of iron storage and iron release in ferritin is nowadays still limited, even less information is currently available about the influence of free metal ions and other brain metalloproteins in these processes.In this sense, this review is an excellent opportunity to collect all the information today available about the influence of metals and metalloproteins in ferritin loading and unloading events, which until now are dispersed in the literature.Furthermore, we will focus on the importance of all the above-mentioned interactions in the brain, since the importance of the correct and safe balance of metals in the brain after their well-known implication in neurodegenerative 52 processes such as the lzheimer's ( ), Parkinson (P ) and prion protein (PP ) diseases is obvious. In this work, we will not only recall the importance and role of ferritin in the brain but also the putative influence of the interaction between ferritin and some metals and/or metalloproteins and other biomolecules on these neurological dysfunctions. The final part of the review will be devoted to draw some guidelines to where the future prospects point to on the basis of the existing information.

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“…c The specific activity of the slow oxidation phase attributed to the core formation versus the Zn(II)-to-ferritin ratio. The specific activity was calculated using an extinction coefficient of 2.5 cm −1 mM −1 [21]…”

Section: Resultsmentioning

confidence: 99%

“…On the basis of a recent paramagnetic-NMR study by Turano et al [20] using bullfrog M-chain ferritin, it has been proposed that with a transient FC substrate site, the Fe(III)–O–Fe(III) product leaves the FC and passes through a channel system in the protein shell, forming transient clusters of increasing nuclearity, and only after oxidation of an approximately 150–200 Fe(II) per protein does the core formation process start. In contrast, recent EPR [21] and kinetic studies [22] have suggested that the FC of the non-heme ferritin from the hyperthermophilic archaeal anaerobe Pyrococcus furiosus (PfFtn) is a stable prosthetic group. We have proposed that after formation of a stable diiron center, Fe(II) on its way to the core is oxidized by the Fe(III) in the FC, and electrons are transferred to another oxidant such as molecular oxygen [22].…”

Section: Introductionmentioning

confidence: 99%

Inhibition and stimulation of formation of the ferroxidase center and the iron core in Pyrococcus furiosus ferritin

2010

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Ferritin is a ubiquitous iron-storage protein that has 24 subunits. Each subunit of ferritins that exhibit high Fe(II) oxidation rates has a diiron binding site, the so-called ferroxidase center (FC). The role of the FC appears to be essential for the iron-oxidation catalysis of ferritins. Studies of the iron oxidation by mammalian, bacterial, and archaeal ferritin have indicated different mechanisms are operative for Fe(II) oxidation, and for inhibition of the Fe(II) oxidation by Zn(II). These differences are presumably related to the variations in the amino acid residues of the FC and/or transport channels. We have used a combination of UV–vis spectroscopy, fluorescence spectroscopy, and isothermal titration calorimetry to study the inhibiting action of Zn(II) ions on the iron-oxidation process by apoferritin and by ferritin aerobically preloaded with 48 Fe(II) per 24-meric protein, and to study a possible role of phosphate in initial iron mineralization by Pyrococcus furiosus ferritin (PfFtn). Although the empty FC can accommodate two zinc ions, binding of one zinc ion to the FC suffices to essentially abolish iron-oxidation activity. Zn(II) no longer binds to the FC nor does it inhibit iron core formation once the FC is filled with two Fe(III). Phosphate and vanadate facilitate iron oxidation only after formation of a stable FC, whereupon they become an integral part of the core. These results corroborate our previous proposal that the FC in PfFtn is a stable prosthetic group, and they suggest that its formation is essential for iron-oxidation catalysis by the protein.

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The dinuclear iron‐oxo ferroxidase center of Pyrococcus furiosus ferritin is a stable prosthetic group with unexpectedly high reduction potentials

Cited by 24 publications

References 22 publications

Crystal structure of the ferritin from the hyperthermophilic archaeal anaerobe Pyrococcus furiosus

Crystal structure of the ferritin from the hyperthermophilic archaeal anaerobe Pyrococcus furiosus

Ferritin iron uptake and release in the presence of metals and metalloproteins: Chemical implications in the brain

Inhibition and stimulation of formation of the ferroxidase center and the iron core in Pyrococcus furiosus ferritin

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