Comparison of the three-dimensional structures of recombinant human H and horse L ferritins at high resolution 1 1Edited by R. Huber

Hempstead, Paul D.; Yewdall, S J; Fernie, Alisdair R.; Lawson, David M.; Artymiuk, Peter J.; Rice, David W.; Ford, Geoffrey C.; Harrison, Pauline M.

doi:10.1006/jmbi.1997.0970

Cited by 294 publications

(190 citation statements)

References 71 publications

(93 reference statements)

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“…Each ferritin subunit shows the characteristic fourhelix bundle tertiary structure completed by a fifth helix (Fig. 1A) (13,16). The protein models are almost complete, with the exception of the two initial and the three final residues of HoLf and the two starting residues in the HuLf sequence.…”

Section: Significancementioning

confidence: 99%

“…Despite several structures of HuLf and HoLf, ferritins have been determined in complex with different metal ions (13,16,19), and no structural observation of iron binding to the mineralization site has been reported in the literature, the only iron(III) ion reported in HoLf being bound to an exogenous ligand (20). To the goal of obtaining insights into the ferritin biomineralization process, we have obtained the crystal structures of the iron-loaded HuLf and HoLf cages.…”

Section: Significancementioning

confidence: 99%

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Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster

Pozzi

Ciambellotti

Bernacchioni

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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X-ray structures of homopolymeric L-ferritin obtained by freezing protein crystals at increasing exposure times to a ferrous solution showed the progressive formation of a triiron cluster on the inner cage surface of each subunit. After 60 min exposure, a fully assembled (μ 3 -oxo)Tris[(μ 2 -peroxo)(μ 2 -glutamato-κO:κO′)](glutamato-κO)(diaquo)triiron(III) anionic cluster appears in human L-ferritin. Glu60, Glu61, and Glu64 provide the anchoring of the cluster to the protein cage. Glu57 shuttles incoming iron ions toward the cluster. We observed a similar metallocluster in horse spleen L-ferritin, indicating that it represents a common feature of mammalian L-ferritins. The structures suggest a mechanism for iron mineral formation at the protein interface. The functional significance of the observed patch of carboxylate side chains and resulting metallocluster for biomineralization emerges from the lower iron oxidation rate measured in the E60AE61AE64A variant of human L-ferritin, leading to the proposal that the observed metallocluster corresponds to the suggested, but yet unobserved, nucleation site of L-ferritin.L-ferritin | metallocluster | nucleation site | biomineralization | X-ray

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Section: Significancementioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster

Pozzi

Ciambellotti

Bernacchioni

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Thus both the length and the sequence in the C/D loop are important for pore function. Possibly, when the ferritin gated pore is folded or closed, aspartate 122 blocks reduction of the ferric mineral since, in crystal structures, the C/D loop is pointing into the funnel created by the pore with aspartate 122 at the base of the pore [11,25,26].…”

Section: Identifying Ferritin Nanocage Pore Gatesmentioning

confidence: 99%

“…Current models of ferrous ion entry through the gated pores into the nanocage are based on competition with other metal ions [4][5][6][7][8][9], mutagenesis of non-gating residues around the pore [8,10], and co-crystal structures with metal inhibitors [11]. The model is weakened by the absence of crystal structures of the mutant proteins, by the multiple sites for metal inhibitor binding in addition to the pores, and by studies suggesting other ferrous ion entry sites besides the gated pores [12,13].…”

Section: Introductionmentioning

confidence: 99%

Gated pores in the ferritin protein nanocage

Theil

Liu

Tosha

2008

Inorganica Chimica Acta

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Synopsis and pictogram: Gated pores in the ferritin family of protein nanocages, illustrated in the pictogram, control transfer of ferrous iron into and out of the cages by regulating contact between hydrated ferric oxide mineral inside the protein cage, and reductants such as FMNH 2 on the outside. The structural and functional homology between the gated ion channel proteins in inaccessible membranes and gated ferritin pores in the stable, water soluble nanoprotein, make studies of ferritin pores models for gated pores in many ion channel proteins.Properties of ferritin gated pores, which control rates of FMNH 2 reduction of ferric iron in hydrated oxide minerals inside the protein nanocage, are discussed in terms of the conserved pore gate residues (arginine 72-apspartate 122 and leucine 110-leucine 134), of pore sensitivity to heat at temperatures 30 °C below that of the nanocage itself, and of pore sensitivity to physiological changes in urea (1-10 mM). Conditions which alter ferritin pore structure/function in solution, coupled with the high evolutionary conservation of the pore gates, suggest the presence of molecular regulators in vivo that recognize the pore gates and hold them either closed or open, depending on biological iron need. The apparent homology between ferrous ion transport through gated pores in the ferritin nanocage and ion transport through gated pores in ion channel proteins embedded in cell membranes, make studies of water soluble ferritin and the pore gating folding/unfolding a useful model for other gated pores.

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“…The possible pathways by which iron might penetrate into the protein include these channels. The X-ray crystallographic observation of metal binding sites suggests that the 3-fold channels are the most likely route of iron entry into animals ferritins (Lawson et al 1991;Hempstead et al 1997;Granier et al 1998).…”

Section: Introductionmentioning

confidence: 99%

EPR Studies of Recombinant Horse L-Chain Apoferritin and its Mutant (E 53,56,57,60 Q) with Haemin

2006

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Structural similarities between ferritins and bacterioferritins have been extensively demonstrated. However, there is an essential difference between these two types of ferritins: whereas bacterioferritins bind haem, in-vivo, as Fe(II)-protoporphyrin IX (this haem is located in a hydrophobic pocket along the 2-fold symmetry axes and is liganded by two axial Met 52 residues), eukaryotic ferritins are non-haem iron proteins. However, in in-vivo studies, a cofactor has been isolated from horse spleen apoferritin similar to protoporphyrin IX; in in-vitro experiments, it has been shown that horse spleen apoferritin is able to interact with haemin (Fe(III)-protoporphyrin IX). Studies of haemin incorporation into horse spleen apoferritin have been carried out, which show that the metal free porphyrin is found in a pocket similar to that which binds haem in bacterioferritins (Pre´cigoux et al. 1994 Acta Cryst D50, 739-743). A mechanism of demetallation of haemin by L-chain apoferritins was subsequently proposed (Crichton et al. 1997 Biochem 36, 15049-15054) which involved four Glu residues (E 53,56,57,60) situated at the entrance of the hydrophobic pocket and appeared to be favoured by acidic conditions. To verify this mechanism, these four Glu have been mutated to Gln in recombinant horse L-chain apoferritin. We report here the EPR spectra of recombinant horse L-chain apoferritin and its mutant with haemin in basic and acidic conditions. These studies confirm the ability of recombinant L-chain apoferritin and its mutant to incorporate and demetallate the haemin in acidic and basic conditions.

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Comparison of the three-dimensional structures of recombinant human H and horse L ferritins at high resolution 1 1Edited by R. Huber

Cited by 294 publications

References 71 publications

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster

Gated pores in the ferritin protein nanocage

EPR Studies of Recombinant Horse L-Chain Apoferritin and its Mutant (E 53,56,57,60 Q) with Haemin

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Comparison of the three-dimensional structures of recombinant human H and horse L ferritins at high resolution 1 1Edited by R. Huber

Cited by 294 publications

References 71 publications

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ 3 -oxo)Tris[(μ 2 -peroxo)] triiron(III) cluster

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ 3 -oxo)Tris[(μ 2 -peroxo)] triiron(III) cluster

Gated pores in the ferritin protein nanocage

EPR Studies of Recombinant Horse L-Chain Apoferritin and its Mutant (E 53,56,57,60 Q) with Haemin

Contact Info

Product

Resources

About

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster

Chemistry at the protein–mineral interface in L-ferritin assists the assembly of a functional (μ ³ -oxo)Tris[(μ ² -peroxo)] triiron(III) cluster