FIGURE 3.

Time course of selective C3bB(Mn²⁺) C3 proconvertase assembly (A) and C3bBb(Mg²⁺) C3 convertase formation (B) detected by microplate/WB assays. C3bB(Mn²⁺) and C3bBb(Mg²⁺) complexes were obtained by incubating C3b-coated wells at time points indicated with 1000 ng/ml FB in the presence or in the absence of 5 ng/ml FD and 2 mm MnCl₂ at 37 °C or 10 mm MgCl₂ at 25 °C, respectively. The amount of C3bB assembled and of C3bBb formed was calculated as the intensity of B band (93 kDa) and Bb band (60 kDa), respectively, and results are reported in the bottom graphs as pixel²·10⁶. Results of a representative microplate/WB experiment of n = 3 are shown.