Fold: Trypsin-like serine proteases

barrel, closed; n=6, S=8; greek-key
duplication: consists of two domains of the same fold

Lineage:

1. Root: scop
2. Class: All beta proteins
3. Fold: Trypsin-like serine proteases
   barrel, closed; n=6, S=8; greek-key
   duplication: consists of two domains of the same fold

Superfamilies:

1. Trypsin-like serine proteases (4)
   1. Prokaryotic proteases (9)
   2. Eukaryotic proteases (48)
   3. Viral proteases (4)
      beta sheet in the first domain is opened rather than forms a barrel
   4. Viral cysteine protease of trypsin fold (3)