(A) APPIWT shows limited interactions with the
mesotrypsin S3′ subsite. Mesotrypsin cartoon and surface are
shown in gray, with Phe-41 and Lys-60 in
orange; APPIWT is shown in
blue, with Ile-18 in cyan (PDB entry: 3L33).
(B) Phe-18 of APPIM17G/I18F/F34V forms hydrophobic,
ring-stacking, and amino-aromatic interactions with mesotrypsin Phe-41 and
Lys-60 residues. Mesotrypsin is rendered and colored as above, with
APPIM17G/I18F/F34V in yellow and mutated
residues in green.