Figure 4.

The effect of Fe²⁺ on the stability and nanoparticle (NP) formation of receptor-binding domain (RBD)-[SSG]-FR. (A) Purification yields of RBD-[SSG]-FR from cell culture at various concentrations of Fe²⁺ (0, 200, 500, and 1,000 mM). The data are presented as mean ± SD of duplicate experiments. All p-values were determined using Student’s two-tailed tests (**p < 0.01). After purification, the NPs were examined by size exclusion chromatography (B), transmission electron microscopy (C), and dynamic light scattering (D). Arrowheads in (B) indicate the eluted RBD-[SSG]-FR.