FIGURE 4.

Characterization of Zn²⁺ binding to mutant MG53 proteins. A, purified MBP-MG53 fusion proteins expressed in E. coli were analyzed by SDS-PAGE. B, the Zn²⁺-binding capacity of the MBP-MG53 mutant fusion proteins was characterized by TSQ staining of amylase beads. Representative fluorescence images were taken after washing out the unbound TSQ. C, the purified MBP fusion proteins were used to assay for the Zn²⁺-binding capacity with an established biochemical protocol. The relative Zn²⁺ concentration in each MBP-MG53 fusion protein was quantified. Data from multiple trials were averaged and normalized to WT MBP-MG53 (mean ± S.E., n = 5). *, p < 0.05; **, p < 0.001.