FIGURE 9.

The HsBBS9_1–407 β-propeller does not form a homodimer in solution, unlike the HsBBS9_405–887 C-terminal half. A, overlaid absorbance traces from SEC experiment on HsBBS9_1–407 at 1 mg/ml (light gray), 2.5 mg/ml (gray), 5 mg/ml (dark gray), and 10 mg/ml (black). Elution volume is indicated above each peak. A.U., absorbance units. B, top, absorbance data, at 280 nm, for HsBBS9_1–407 from equilibrium AUC experiment plotted against cell radius position in centimeters (see “Experimental Procedures” for details). Individual absorbance measures are depicted as blue dots, and non-linear least squares fits are shown (red lines). Data and fits are plotted for HsBBS9_1–407 at 9,500 rpm (top), 12,000 rpm (middle), and 18,000 rpm (bottom). B, bottom, residuals for model fit to data. The zero position is indicated by a black line. C, overlaid absorbance traces from SEC experiment on HsBBS9_405–887 at 1 mg/ml (light gray), 2.5 mg/ml (gray), 5 mg/ml (dark gray), and 10 mg/ml (black). D, absorbance data, at 280 nm, for HsBBS9_405–887 from equilibrium AUC experiment plotted as in B. Data and fits are plotted for HsBBS9_405–887 at 9,500 rpm (top), 14,000 rpm (middle), and 17,000 rpm (bottom).