FIGURE 3.

Kinetic analysis of C3bB(Mg²⁺) assembly and dissociation on a C3b-coated biosensor surface. C3b (2890 response units (RU)) was covalently attached to a biosensor surface and treated for 60 s with various concentrations of recombinant factor B (A), factor B E446V (B), or factor B E207A (C) in Mg²⁺ HEPES buffer followed by buffer alone. The resulting profiles were subjected to kinetic analysis using a two-state conformational change model (10) and the BIAevaluation software. The thin black lines represent the original data profiles, and the thick gray lines represent the global best fit (see calculated kinetic constants in Table 1).