Fig. 4

Schematic representation of SOD1 secondary structure with positions of residues (a) forming 28 destructive hydrogen bonds that are marked, and (b) with most averaged mechanical stiffness, \( \overline{K_i} \), highlighted. Chain A is shown on the left and chain F on the right. In parentheses are the number of residues involved in forming hydrogen bonds of a chain. The E, S, Z, and G letters in circles denote electrostatic, disulfide, zinc-binding, and “greek-key” loops, respectively. Letters A and I inside the vertical rectangles indicate those residues involved in the contact of SOD1 aggregates and residues at the interface between subunits, respectively. Labels ss, cu, and zn inside squares stand for residues forming disulfide bond, copper-, and zinc-binding sites, respectively. Horizontal rounded arrows with B1–B8 specify corresponding beta-sheets from 1 to 8. The degree of filling in the circles, squares, and arrows reflects the percentage of residues falling in each element. Numbers below the schemes signify residue positions missed in the markup