SOD1 and amyotrophic lateral sclerosis: In calculating the correlated motions of residue pairs [20], we find profound differences in the motions of residues corresponding to key structural features of SOD1 known to promote integrity of the properly folded structure (Fig 2): namely, both cysteines of the intra-monomer Cys57-Cys146; the Cu-binding histidines 46, 48, and 120; the Cu-Zn bridging ligand His63; the Zn-coordinating residues His71, His80, and Asp83; and the structurally important residue Asp124, which forms a crucial connection between Cu- and Zn- binding residues and whose mutation has been linked to ALS [21].