Figure 3

SANS curve for NpSRII/NpHtrII at 4.0 M NaCl and corresponding distance distribution functions. (A) Experimental scattering curve for NpSRII/NpHtrII at 4.0 M NaCl (orange squares) fitted with χ² = 5.5 to a theoretical curve (blue line) calculated for a mixture of NpSRII/NpHtrII dimers and trimers of dimers which inter-dimer contacts are induced both between the transmembrane regions of dimers and their cytoplasmic tips (Fig. 4A). (B) Experimental scattering curve for NpSRII/NpHtrII at 4.0 M NaCl (orange squares) fitted with χ² = 1.3 to a theoretical curve (blue line) calculated for a mixture of NpSRII/NpHtrII dimers and "tripod"-shaped trimers of dimers (Fig. 4B). (C) Distance distribution function calculated from the experimental curve shown in (A,B) (orange squares), and theoretical distance distribution functions of the dimers (grey line), the "tripod"-shaped (Fig. 4B) trimers of dimers (brown line) and the "transmembrane-bound" conformation of trimer of dimers of the NpSRII/NpHtrII (Fig. 4A) (black line). For greater clarity, distance distribution functions were normalized to obtain maximum values of 1.0 for the experimental and 0.6 for the theoretical curves.