Class: Small proteins

Usually dominated by metal ligand, heme, and/or disulfide bridges

Lineage:

1. Root: scop
2. Class: Small proteins [56992]
   Usually dominated by metal ligand, heme, and/or disulfide bridges

Folds:

1. Insulin-like [56993] (1)
   nearly all-alpha
   can be classified as disulphide-rich
2. Toxic hairpin [57006] (2)
   disulphide crosslinked alpha-helical hairpin
3. Knottins (small inhibitors, toxins, lectins) [57015] (18)
   disulphide-bound fold; contains beta-hairpin with two adjacent disulphides
4. PMP inhibitors [57282] (1)
   disulphide-rich fold; all-beta: 3 antiparallel strands
5. Midkine [57287] (1)
   disulphide-rich fold; all-beta: 3 antiparallel strands
6. TSP-1 type 1 repeat [82894] (1)
   disulphide-rich fold; all-beta: 3 antiparallel strands
7. Amb V allergen [57295] (1)
   disulphide-rich; alpha+beta: 3 antiparallel strands followed by a short alpha helix
8. Snake toxin-like [57301] (1)
   disulphide-rich fold: nearly all-beta
9. BPTI-like [57361] (1)
   disulphide-rich alpha+beta fold
10. Defensin-like [57391] (1)
    Disulphide-rich fold, nearly all-beta
11. Hairpin loop containing domain-like [57413] (1)
    alpha+beta fold with two crossing loops
12. Neurotoxin III (ATX III) [57418] (1)
    disulphide-rich fold
13. LDL receptor-like module [57423] (1)
    disulphide-rich calcium-binding fold
14. Crambin-like [57428] (1)
    disulphide-rich alpha+beta fold
15. Kringle-like [57439] (1)
    disulphide-rich fold; nearly all-beta
16. Ovomucoid/PCI-1 like inhibitors [57466] (1)
    disulphide-rich small alpha+beta fold
17. Trefoil [57491] (1)
    disulphide-rich fold; duplication: consists of two homologous domains
18. Cystine-knot cytokines [57500] (1)
    disulphide-rich fold; common core is all-beta
19. Complement control module/SCR domain [57534] (1)
    disulphide-rich all-beta fold
20. Sea anemone toxin k [57545] (1)
    disulphide-rich all-alpha fold
21. Blood coagulation inhibitor (disintegrin) [57551] (1)
    small disulphide-rich
22. Methylamine dehydrogenase, L chain [57560] (1)
    disulphide-rich; nearly all-beta
23. Serine proterase inhibitors [57566] (1)
    disulphide-rich; nearly all-beta
24. TB module/8-cys domain [57580] (1)
    disulphide-rich; alpha+beta
25. TNF receptor-like [57585] (1)
    duplication: consists of three similar disulphide-rich domains
26. Heparin-binding domain from vascular endothelial growth factor [57592] (1)
    duplication: consists of two similar disulphide-rich domains, alpha+beta
27. Antifungal protein (AGAFP) [57597] (1)
    disulphide-rich; all-beta: open barrel, 5 strands; OB-fold-like
28. Fibronectin type I module [57602] (1)
    disulphide-rich, all-beta
29. Thyroglobulin type-1 domain [57609] (1)
    disulphide-rich, alpha+beta
30. Type X cellulose binding domain, CBDX [57614] (1)
    disulphide-rich, alpha+beta
31. Cellulose docking domain, dockering [64570] (1)
    disulphide-rich, alpha+beta
32. Carboxypeptidase inhibitor [57619] (1)
    disulphide-rich, alpha+beta
33. Serine proteinase inhibitor lekti [69958] (1)
    disulphide-rich, alpha+beta
34. nvertebrate chitin-binding proteins [57624] (1)
    disulphide-rich
35. Pheromone ER-23 [69963] (1)
    disulphide-rich, all-alpha
36. Mollusk pheromone [90182] (1)
    disulphide-rich; all-alpha
37. Apical membrane antigen 1 [82909] (1)
    disulphide-rich, alpha+beta
38. Somatomedin B domain [90187] (1)
    disulphide-rich
39. Notch domain [90192] (1)
    disulphide-rich; all-alpha; calcium-binding
40. GLA-domain [57629] (1)
    Calcium ion-bound
41. Cholecystokinin A receptor, N-domain [57641] (1)
    a few helical turns and a disulide-crosslinked loop
42. HIV-1 VPU cytoplasmic domain [57646] (1)
    a few helical turns assembled without a hydrophobic core?
43. HIPIP (high potential iron protein) [57651] (1)
    folds around 4Fe-4S cluster
44. Ferredoxin thioredoxin reductase (FTR), catalytic beta chain [57661] (1)
    folds around 4Fe-4S cluster
45. C2H2 and C2HC zinc fingers [57666] (1)
    alpha+beta metal(zinc)-bound fold: beta-hairpin + alpha-helix
46. Zn2/Cys6 DNA-binding domain [57700] (1)
    all-alpha dimetal(zinc)-bound fold
47. Glucocorticoid receptor-like (DNA-binding domain) [57715] (1)
    alpha+beta metal(zinc)-bound fold
48. Retrovirus zinc finger-like domains [57755] (1)
    metal(zinc)-bound fold
49. Rubredoxin-like [57769] (12)
    metal(zinc or iron)-bound fold; sequence contains two CX(n)C motifs, in most cases n = 2
50. Ribosomal protein L36 [57839] (1)
    zinc-bound beta-ribbon motif
51. Zinc-binding domain of translation initiation factor 2 beta [75688] (1)
    zinc-bound beta-ribbon motif
52. B-box zinc-binding domain [57844] (1)
    zinc-bound alpha+beta motif
53. RING/U-box [57849] (1)
    dimetal(zinc)-bound alpha+beta motif; structurally diverse
54. Pyk2-associated protein beta ARF-GAP domain [57862] (1)
    zinc-bound alpha+beta motif
55. Metallothionein [57867] (1)
    metal(iron)-bound fold
    duplication: consists of clear structural/sequence repeats
56. Zinc domain conserved in yeast copper-regulated transcription factors [57878] (1)
    metal(zinc)-bound alpha+beta fold
57. Ada DNA repair protein, N-terminal domain (N-Ada 10) [57883] (1)
    metal(zinc)-bound alpha+beta fold
58. Cysteine-rich domain [57888] (1)
    dimetal(zinc)-bound alpha+beta fold
59. FYVE/PHD zinc finger [57902] (1)
    dimetal(zinc)-bound alpha+beta fold
60. Zn-binding domains of ADDBP [57916] (1)
    metal(zinc)-bound alpha+beta fold
61. Inhibitor of apoptosis (IAP) repeat [57923] (1)
    metal(zinc)-bound alpha+beta fold
62. CCCH zinc finger [90228] (1)
    metal(zinc)-bound alpha+beta fold
63. Zinc finger domain of DNA polymerase-alpha [90233] (1)
    Zn-binding, all-alpha fold
64. TAZ domain [57932] (1)
    all-alpha fold; Zn-binding sites are in the loops connecting helices
65. Cysteine-rich DNA binding domain, (DM domain) [82926] (1)
    alpha-helical fold with two Zn-binding sites
66. Cysteine-rich domain of the chaperone protein DnaJ. [57937] (1)
    metal(zinc)-bound extended beta-hairpin fold