Molecular dissection of interactions between components of the alternative pathway of complement and decay accelerating factor (CD55)
CL Harris, RJM Abbott, RA Smith, BP Morgan… - Journal of Biological …, 2005 - ASBMB
The complement regulatory protein decay accelerating factor (DAF; CD55), inhibits the
alternative complement pathway by accelerating decay of the convertase enzymes formed
by C3b and factor B. We show, using surface plasmon resonance, that in the absence of Mg
2+, DAF binds C3b, factor B, and the Bb subunit with low affinity (KD, 14±0.1, 44±10, and
20±7 μm, respectively). In the presence of Mg 2+, DAF bound Bb or the von Willebrand
factor type A subunit of Bb with higher affinities (KD, 1.3±0.5 and 2.2±0.1 μm, respectively) …
alternative complement pathway by accelerating decay of the convertase enzymes formed
by C3b and factor B. We show, using surface plasmon resonance, that in the absence of Mg
2+, DAF binds C3b, factor B, and the Bb subunit with low affinity (KD, 14±0.1, 44±10, and
20±7 μm, respectively). In the presence of Mg 2+, DAF bound Bb or the von Willebrand
factor type A subunit of Bb with higher affinities (KD, 1.3±0.5 and 2.2±0.1 μm, respectively) …
