Fig. 5

ARMS2 interacts with properdin. a Binding of ARMS2 (500 ng, 1 h) to immobilized C3 convertase components properdin, C3, C3b, iC3b, C3c, C3d, and factor B (each 500 ng). Error bars represent mean ± s.d. (n = 4, ***p = 0.0001, properdin versus buffer). A stippled lane indicates background binding. b Properdin (12.5–100 nM) binding to immobilized ARMS2 or HSA. Error bars represent mean ± s.d. (n = 3, **p = 0.001, 12.5 nM versus 100 nM properdin). c C3b (4–32 nM, 1 h) binding to properdin (100 nM) attached to immobilized ARMS2 is increased but not to immobilized ARMS2 alone. (n = 3, ***p = 0.001, 4 nM versus 32 nM C3b). d Affinity constant of the interaction between ARMS2 and properdin was determined by biolayer interferometry. Recombinant ARMS2 was immobilized to the biosensor, and interaction of properdin was determined (mean value ± s.d. of two independent experiments). e Recombinant ARMS2 binds properdin within the C-teminal domain. Properdin binding was evaluated to three peptides of ARMS2 immobilized to the plate. Amino acid sequences of the peptides are indicated