FIGURE 3.

The comparison between the formation of collapsed state (I_C) and that of secondary structure (I_S). The formation of I_C has been monitored by r_H using FCS data (black squares), whereas far UV CD at 222 nm (red squares) has been used to monitor the formation of I_S. The data containing the variation of r_H with sodium perchlorate concentration has been fit to a two-state unfolding transition as shown by the black line. The line through the CD data (red line), on the other hand, is for the presentation only and not a fit using a physically validated equation. All measurements have been carried out at pH 2.