Figure 3. (A) Canonical WT TTR sequence, peptides frequently observed in mass spectrometry experiments are shown in blue. Highlighted residues have published chemical modifications that could serve as fold-stability markers (B) The TTR monomer folds into two discrete beta sheets and a small alpha helix (PDB structure 1BZE) (C) The consensus model of the tetramer has four monomers (each in a different color) interacting along the edges of the beta sheets which would stabilize the protein structure in these regions (Model incorporates PDB 1BZE and 1BZ8).