Figure 12.

X-ray and neutron-scattering curve fits and Kratky analyses for the best-fit IgG2 models. The experimental data are indicated by white open circles, and the modeled best-fit curve is indicated in red. The models show 0.75-nm separations between each of the four pairs of cysteines in the IgG2 hinge. The X-ray best fits correspond to 0.5 mg/ml IgG2 in PBS-50 (A), 1 mg/ml IgG2 in PBS-137 (B), and 1.5 mg/ml IgG2 in PBS-250 (C). The neutron best fits correspond to 0.45 mg/ml IgG2 in PBS-50 (D), 1 mg/ml IgG2 in PBS-137 (E), and 1.99 mg/ml IgG2 in PBS-250 (F) in 100% ²H₂O. The insets correspond to the experimental (black) and best-fit modeled (red) P(r) curves, in which M1, M2, and L are arrowed. G–L, corresponding Kratky plots for the same six comparisons between experiment and models are shown.