FIGURE 8.

Recovery of the intramolecular disulfide bond after remetalizing apo hSOD1. The polyprotein I27₃SODI27₃ was treated to remove the metals and then incubated with solutions containing Cu²⁺ and Zn²⁺ to reintroduce these metals in hSOD1. Cleavage of the disulfide bond could be detected in pulling experiments in the presence of TCEP. Black dots indicate the unfolding of the six I27 modules, whereas the gray dot marks the unfolding of hSOD1 up to the disulfide bond. Red arrowhead indicates the rupture of disulfide bond 57–146, rendering a step of 31 nm.