Peptide sequences binding to patient 12's paraprotein. The peptide inserts in the phage library are 20 amino acids long. The sequences are aligned by their consensus residues, which are enclosed within the boxes. The fact that so many consensus sequences are immediately adjacent to the carboxy terminus (right-hand side) of the peptide insert indicates that the next (invariant) amino acid is likely identical to the native sequence. Otherwise, the consensus sequences should have been randomly positioned within the peptide insert. For that reason, we included the next amino acid on the carboxyl side (glycine, G) as part of the consensus sequence. Glycines that are part of the invariant carboxy terminus are italicized (G).