Fig 1.
Microscopic images of apoferritin hydrogels.
(A) Swelled, (B) dried, and (C) reswelled.
Fig 2.
MALDI-TOF MS spectra of apoferritin hydrogel.
(A) MALDI-TOF MS spectra of apoferritin hydrogel and (B) MALDI-TOF MS spectra of Fer8 solution after heating the apoferritin hydrogel at 90°C for 30 min. Wide range (top) and expanded range (m/z 17,000–21,000) (bottom). Sinapinic acid was used as a matrix.
Fig 3.
Microscopic images of apoferritin hydrogels before and after incubation in various solutions.
(A) 1 M HCl and (B) 2-ME, and methanol. The hydrogels were incubated for1 h.
Fig 4.
Young’s modulus of the swelled apoferritin hydrogel measured with AFM.
Fig 5.
SEC analysis of the solution obtained after heating the apoferritin hydrogel at 90°C for 30 min.
(A) Chromatograms of the solution obtained after heating the apoferritin hydrogel and of standard proteins (ferritin, 440 kDa; aldolase, 158 kDa; conalbumin, 75 kDa; ovalbumin, 44 kDa; cytochrome c, 12 kDa). (B) Standard curve obtained by least-square fitting of the partition coefficient (Kav) plots of standard proteins (closed circles). Peaks obtained in the chromatogram of the solution obtained by heating the apoferritin hydrogel are labeled with the molecular size (kDa) estimated by the standard curve. The plots of the apoferritin hydrogel after heating (open circles) are depicted with the estimated molecular weight (kDa).
Fig 6.
Circular dichroism spectra of Fer8 solution.
Fer8 solution obtained after heating the apoferritin hydrogel at 90°C for 30 min (solid line) and purified Fer8 solution (broken line).
Fig 7.
Negative-stain TEM images of apoferritin hydrogel.
(A) Low and (B high resolution.
Fig 8.
Schematic image of apoferritin hydrogel formation.
Fig 9.
Metal adsorption of apoferritin hydrogel.
Fe3+, Co2+, Ni2+, and Cu2+ ions are investigated. The apoferritin hydrogel was incubated sequentially in the presence of 100 mM metal ions for 1 h, in pure water for 3 h, and in 100 mM EDTA for 1 h. Fe(III)Cl3, Co(II) acetate, Ni(II)Cl2, and Cu(II)Cl2 solutions were used. The pictures of the hydrogel before the addition of the metal ions were taken under air, whereas other figures were taken under solutions.
Table 1.
Amounts of metal ions adsorbed to the apoferritin hydrogel.