0,000 rpm (*open* squares) and 00,000 (*open* circles). Absorbance at 000 nm is plotted against the radial position from the center of the rotor. The fit to the data set (*solid line curves*) corresponds to an ideal species with a molecular mass of 00.0±0.0 kDa (n = 0). Residuals from this fit are shown in the panel at the bottom. Calculations were done with the program Heteroanalysis [@pone.0000000-DeLano0]. 