Analytical ultracentrifugation sedimentation velocity of fully phosphorylated Hsp27 (Hsp27-3P) at 20 °C in the absence of salt in 2 mm Tris, 0. 1 mm EDTA, 0.01% NaN3, 50 μm PMSF, 5 mm DTT, pH 7.5. The concentration-normalized sedimentation distribution function (y axis) is plotted versus the apparent sedimentation coefficient (x axis).