FIGURE 7.

Distance distribution functions P(r) for the five proteins. A–E, for C3, C3u, and C3b in 137 mm NaCl by x-rays, the maximum M is at 5.0 nm; M for C3c is at 4.5 nm; and M for C3d is at 2.5 nm. For C3, C3u, and C3b, the maximum length L is at 16 nm; L for C3c is at 14 nm; and L for C3d is at 7 nm. F–J, the neutron data in 137 mm NaCl showed similar M and L values for the five proteins. K–O, the x-ray data in 50 mm NaCl showed L values for C3 of 15 nm (0.5 mg/ml), 16 nm (0.8 mg/ml), and 19 nm (1.25 mg/ml). For C3u, the L values increased from 16 to 20 nm between 0.17 and 1.29 mg/ml. For C3b, the L values increased from 17 to 20 nm between 0.4 and 1.40 mg/ml. For C3c, the L values of 14 nm were unchanged between 0.16 and 1.25 mg/ml. C3d showed L values of 6 nm (0.15 mg/ml), 9 nm (0.5 mg/ml), and 12 nm (1.41 mg/ml) and two peaks denoted M1 and M2 at 1.41 mg/ml.