Figure 1.

Crystal structure of stabilized monomeric human cystatin C (PDB code 3NX0, modified to include flexible N-terminal residues that were not resolvable in the original structure). a, annotated structure with substrate-binding residues emphasized. Papain, cathepsin-binding site: magenta. Legumain-binding site: blue. b, domain-swapped (PDB code 1R4C). c, propagated domain swapped (hypothesized, adapted from Ref. 21). d, amyloid-prone regions identified by AMYLPRED algorithm (68) highlighted in red.