Figure 4. Cytochrome b backbone movements induced by inhibitor binding. The structures of entry 1BCC (native), 3BCC (Stig + Anti), and two unsubmitted datasets containing only stigmatellin (stig) or antimycin (anti) were superimposed so as to minimize the rms deviation of C-a atoms of residues 32-129, 180-248, and 294-380. Then the four pairwise comparisons indicated were made by subtracting the coordinates of corresponding C-a atoms in the superimposed structures. To reduce noise and emphasize changes involving more than a single residue, the resulting values were averaged in a window of 3 residues. The resulting value is plotted vs residue number to indicate where the changes occur. A cartoon representing the secondary structure and surface exposure (prepared by the program Procheck) is aligned above.