c(s) distribution of apoE-(72-166) proteins in PBS with or without DHPC. The sedimentation velocity data was fitted with the SEDFIT program using the continuous c(s) distribution model . The fitted curves for apoE2-, apoE3-, and apoE4-(72-166) are shown as dotted, dash, and solid lines, respectively. Panels A-D: proteins were in PBS, and with 5 mM, 50 mM, or 100 mM DHPC, respectively. Insets, grayscale of the residual bit map showing the quality of data fitting.