FIG 5.

CP binds Cu with high affinity. Chelator competition experiments to estimate the affinity of CP for Cu were performed in triplicate as described in Materials and Methods. The binding of Cu²⁺ to WT CP-CS (A), ΔS1ΔS2 (B), ΔS1 (C), and ΔS2 (D) was assessed by tracking the change in fluorescence of Cu²⁺-bound fluorescent chelator fluozin-3 as protein was titrated into the solution.