FIGURE 2.
CagL conformational changes in solution. A, top, sedimentation equilibrium experiment of CagL (38 μm) in 50 mm sodium acetate, 150 mm sodium chloride, pH 4.5, with rotor speeds of 20,000, 23,000, and 26,000 rpm (blue, red, and green curves, respectively). Bottom, residuals of fitted data for each curve. B, same experiment as described in A except conducted in 50 mm Tris, 150 mm sodium chloride, pH 7.5. Dimerization constants were measured from these data as 380 ± 115 μm at pH 4.5 and 170 ± 55 μm at pH 7.5. C, sedimentation velocity experiment of CagL (10 μm) at 50,000 rpm in 50 mm sodium acetate, 150 mm sodium chloride, pH 4.5 (blue crosses), or 50 mm Tris, 150 mm sodium chloride, pH 7.5 (green crosses). Fitted data are shown as solid lines and the residuals (bottom) are plotted. CagL sediments with an s20, w* of 1.9 and 2.2 for pH 4.5 and 7.5, respectively.