Figure 4.

Binding of recombinant and purified mutant factor H protein to C3d analyzed by surface plasmon resonance. (a) The wild-type FH8-20 protein (solid line), mutant proteins FH8-20/R1210C (dotted line), and FH8-20/R1215G (dashed line) were injected at a concentration of 2–3 μg/ml into a flow cell coupled with C3d. The binding of the wild-type protein is apparent from the distinct association and dissociation phases of the binding curve, whereas the binding of the mutants is decreased. All recombinant proteins were tested on two different chip surfaces coated with C3d, and representative figures are shown. (b) Binding of purified mutant factor H (FH) (E1172Stop) to C3b was assayed and compared with that of purified native factor H.