Fig. 3: Effect of protein structure on SOD-like activity and iron/phosphorous ratio of ferritin.

a SOD-like activity and (b) P/Fe ratio of HFn, pfFn and pyFn reconstituted in the same buffer (molar ratio of Pi/Fe = 1:1). c SOD-like activities of reconstituted HFn, pfFn and pyFn in the same total iron content. d The surface potential of the whole structure and three-fold axis of the HFn and Bfr (P. aeruginosa) with the amino acids around the three-fold axis marked in the bottom; the colors referred to electrostatic potential, red: negative, white: neutral, blue: positive. e Representative negative stained TEM image of the three-fold pore mutated HFn of three independent experiments with similar results; inset figures represented partially enlarged images; the scale bar referred to 50 nm, inset scale bar referred to 20 nm. f SOD-like activity and (g) P/Fe ratio of the biomineralized WT (HFn-WT) and mutated HFn (HFn-3-fold-M). h Negative stained and unstained TEM images of the H/LFn and MFn of three independent experiments with similar results; inset figures represented partially enlarged images; the scale bar referred to 50 nm, inset scale bar referred to 20 nm. i SOD-like activity of biomineralized human HFn, MFn, H/LFn and the archaeal pfFn, pyFn. p valve between HFn-Fe and H/LFn-Fe was 0.8465, and between HFn-Fe and MFn-Fe was 0.1187. j SOD-like activity of reconstituted human HFn, MFn, H/LFn, and the archaeal pfFn, pyFn. All the data are presented as mean ± SD (n = 3 independent experiments). The significant differences were evaluated by the Two-way ANOVA with post-hoc Tukey HSD test for (a, c, i, j), by the One-way ANOVA with post-hoc Tukey HSD test for (b), and by Two-sided unpaired Student’s t-test for (g); ns: not significant, p > 0.05. Source data are provided as a Source Data file.