Distance distribution of four cofilin-actin binding sites at (a) 123K and (b) 310K. Note the distance range ends at 7Å in (a) but at 20Å in (b). Peaks for BS-1 to BS-3 in (a) and (b) are similar, while for BS-4 are very different. These suggest that all four binding site are stable at low temperature, and BS-4 is not as stable as others at the physiological temperature. Residue RMSF distributions of (c) bare filament and (d) cofilactin filament exhibit a much higher RMSF in regions of N/C-terminus, D-loop, residues 230–250, and H-plug (residues 262–274). Each line represents RMSF data for one actin subunit.