Two distinct conformations of factor H regulate discrete complement-binding functions in the fluid phase and at cell surfaces.

ABSTRACT: Factor H (FH) is the major regulator of C3b in the alternative pathway of the complement system in immunity. FH comprises 20 short complement regulator (SCR) domains, including eight glycans, and its Y402H polymorphism predisposes those who carry it to age-related macular degeneration. To better understand FH complement binding and self-association, we have studied the solution structures of both the His-402 and Tyr-402 FH allotypes. Analytical ultracentrifugation revealed that up to 12% of both FH allotypes self-associate, and this was confirmed by small-angle X-ray scattering (SAXS), MS, and surface plasmon resonance analyses. SAXS showed that monomeric FH has a radius of gyration (R_g ) of 7.2-7.8 nm and a length of 25 nm. Starting from known structures for the SCR doma

SUBMITTER: Osborne AJ 

PROVIDER: S-EPMC6222095 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature