Mössbauer spectroscopic studies of human haemosiderin and ferritin

Bell, Susan Groag; Weir, Malcolm; Dickson, D.P.E.; Gibson, J. F.; Sharp, Gaynor; Peters, Timothy J.

doi:10.1016/0167-4838(84)90313-3

Cited by 153 publications

(62 citation statements)

References 12 publications

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“…7). A similar temperature dependence has been reported previously for native and reconstituted ferritins (Bell et al, 1984;Watt et al, 1985;Mann et al, 1987) and for the native and reconstituted bacterioferritins of A. vinelandii (Watt et al, 1986;Mann et al, 1987). These ferritins and the 57FeBFR shown in Fig.…”

Section: Mossbauer Spectroscopysupporting

confidence: 64%

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Overproduction, purification and characterization of the bacterioferritin of Escherichia coli and a C‐terminally extended variant

Andrews

Smith

Hawkins

et al. 1993

European Journal of Biochemistry

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The bacterioferritin (BFR) of Escherichia coli is an iron-sequestering haemoprotein composed of 24 identical polypeptide chains forming an approximately spherical protein shell with a central iron-storage cavity. BFR and BFR-A, a variant with a 14-residue C-terminal extension, have been amplified (120-fold and 50-fold, respectively), purified by a new procedure and characterized. The overproduced BFR exhibited properties similar to those of natural BFR, but the iron content (25-75 non-haem Fe atoms/molecule) was 13-39-fold lower. Two major assembly states of BFR were detected, a 24-subunit protein (tetracosamer) and a novel haem-containing subunit dimer. BFR-L subunits assembled into tetracosamers having the same external-surface properties as BFR, presumably because their C-terminal extensions project into and occupy about 60% of the central cavity.As a result, BFR-A failed to take up iron under conditions that allowed incorporation into BFR in vitro. The haem content of BFR-A (1-2 haemshetracosamer) was lower than that of BFR (3.5-10.5 haems/tetracosamer) and this, together with a difference in the visible spectra of the two haemoproteins, suggested that the C-terminal extensions in BFR-A perturb the haem-binding pockets. A subunit dimer form of BFR-A was not detected. A combination of Mossbauer spectroscopy and electron diffraction showed that the BFR loaded with iron in vitro has a ferrihydrite-like iron core, whereas the in-vivo loaded protein has an amorphous core.

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Section: Mossbauer Spectroscopysupporting

confidence: 64%

“…In spite of a lower iron binding, the blocking temperature (39 K) is similar to the value (38 K) for reconstituted horse spleen ferritin (Mann et al, 1987) and native human ferritin (Bell et al, 1984). It is higher than that reported for reconstituted BFR of A. vinelandii, 22.2 K (Mann et al, 1987).…”

Section: Mossbauer Spectroscopymentioning

confidence: 48%

Overproduction, purification and characterization of the bacterioferritin of Escherichia coli and a C‐terminally extended variant

Andrews

Smith

Hawkins

et al. 1993

European Journal of Biochemistry

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“…The blocking temperatures obtained with· Mossbauer studies for Ferritin II [23] are higher than those for Ferritin I, which agree with our results. Simi larly, greater blocking temperatures than for Fer ritin I were observed for Hemosiderin cores [47], which have smaller average core diameters. than regular Ferritin I and higher average core densi ties.…”

Section: Discussionmentioning

confidence: 99%

A comparison of the magnetic properties of polysaccharide iron complex (PIC) and ferritin

Mohie-Eldin

Frankel

Gunther

1994

Journal of Magnetism and Magnetic Materials

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The synthetic polysaccharide iron complex (PIC) molecule has been suggested as a 'biomimic', i.e. a counterpart, to the naturally occurring biological molecule ferritin with respect to its magnetic properties based on the identification of ferrihydrite as the major mineral in both. Magnetization measurements were used to investigate the magnetic properties of PIC in relation to those of ferritin, as well as to identify differences in such properties between naturally occurring ferritin, which we designate here as Ferritin-I, and ferritin with an artificially high content of Fe 2 + ions bound to its core, which is designated here as Ferritin II. The anisotropy constants K, blocking temperatures TB' magnetic moments m per particle, and number of magnetic moments 'spins' per particle-N sp were found to fit the following relations for PIC and ferritin: K(Ferritin I) < K(PIC) ::s; K(Ferritin 11), TB(FerritinThe magnetic moment per Fe ion was found to be smaller in PIC than Ferritin II due to a stronger antiferromag netic interaction between the Fe ions of PIC. Susceptibility measurements indicated the existence of superantiferro magnetism in PIC and Ferritin I and also showed that most Fe 2 + ions in Ferritin II are bound to its core surface. The enhanced values of K and TB as well as the reduced effect of superantiferromagnetism and the antiferromag netic interaction between the molecules at low temperatures for the Ferritin II indicates the importance of the surface magnetic moments in dominating the magnetic behavior of both PIC and femtin (Ferritin I).

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“…Bell et al [13] have noted that hemosiderin has a higher average blocking temperature than ferritin, although transmission electron microscopy (TEM) suggests a smaller average core diameter for the former. Hemosiderin cores could be considered ferritin cores with higher average density perhaps due to aging and collapse of the DLA structure.…”

Section: Discussionmentioning

confidence: 99%