Fig. 5.

Sedimentation analysis of BSA at 52 mg/ml in PBS. a Interference optical data were acquired in a 3 mm centerpiece (circles, showing every 10th data point of every third scan). The best-fit c_NI(s₀) model (solid lines) with a fixed frictional ratio of 1.45 results in an rmsd of 0.058 fringes, with k_S = 8.4 ml/g and k_D = 10 ml/g. b The associated sedimentation coefficient distribution at 52 mg/ml (magenta) and, for comparison, the distributions obtained in analogous analyses at 28 mg/ml (cyan), 9.8 mg/ml (blue), both also acquired in 3 mm centerpieces, and 1.6 mg/ml (green) acquired in a 12 mm centerpiece. The inset shows integrated dimer fractions at ~6.5 S (solid blue circles) and trimer fractions at ~8 S (solid green triangles) from these c_NI(s₀) analysis accounting for nonideality. The open circles are the apparent dimer fractions from empirical c(s) analyses of the same data neglecting nonideality contributions (Supplementary Fig. 7)