Root: scop

Classes:

1. All alpha (97)
2. All beta (61)
3. Alpha and beta (a/b) (75)
   Mainly parallel beta sheets (beta-alpha-beta units)
4. Alpha and beta (a+b) (101)
   Mainly antiparallel beta sheets (segregated alpha and beta regions)
5. Multi-domain (alpha and beta) (20)
   Folds consisting of more than domain of different class
6. Membrane and cell surface proteins and peptides (10)
   Does not include proteins in the immune system
7. Small proteins (41)
   Usually dominated by metal ligand, heme, and/or disulfide bridges
8. Peptides (50)
   Peptides and fragments
9. Designed proteins (10)
   Experimental structures of proteins with essentially non-natural sequences
10. Non-protein (4)
    PDB entries which are theoretical models, nucleic acids, or other non-proteins