Folds:

1. a.1: Globin-like [46457] (2 superfamilies)

2. a.2: Long alpha-hairpin [46556] (11 superfamilies)

3. a.3: Cytochrome c [46625] (1 superfamily)

4. a.4: DNA/RNA-binding 3-helical bundle [46688] (10 superfamilies)

5. a.5: RuvA C-terminal domain-like [46928] (6 superfamilies)

6. a.6: Putative DNA-binding domain [46954] (1 superfamily)

7. a.7: Spectrin repeat-like [46965] (7 superfamilies)

8. a.8: Bacterial immunoglobulin/albumin-binding domains [46996] (1 superfamily)

9. a.9: Peripheral subunit-binding domain of 2-oxo acid dehydrogenase complex [47004] (1 superfamily)

10. a.10: Protozoan pheromone proteins [47013] (1 superfamily)

11. a.11: Acyl-CoA binding protein-like [47026] (2 superfamilies)

12. a.12: Kix domain of CBP (creb binding protein) [47039] (1 superfamily)

13. a.13: alpha-2-Macroglobulin receptor associated protein (RAP) domain 1 [47044] (1 superfamily)

14. a.14: Thermostable subdomain from chicken villin headpiece [47049] (1 superfamily)

15. a.15: TAF(II)230 TBP-binding fragment [47054] (1 superfamily)

16. a.16: S15/NS1 RNA-binding domain [47059] (1 superfamily)

17. a.17: p8-MTCP1 [47071] (1 superfamily)

18. a.18: T4 endonuclease V [47076] (1 superfamily)

19. a.19: Fertilization protein [47081] (1 superfamily)

20. a.20: PGBD-like [47089] (1 superfamily)

21. a.21: HMG-box [47094] (1 superfamily)

22. a.22: Histone-fold [47112] (1 superfamily)

23. a.23: Open three-helical up-and-down bundle [47143] (4 superfamilies)

24. a.24: Four-helical up-and-down bundle [47161] (12 superfamilies)

25. a.25: Ferritin-like [47239] (1 superfamily)

26. a.26: 4-helical cytokines [47265] (1 superfamily)

27. a.27: Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases [47322] (1 superfamily)

28. a.28: Acyl carrier protein-like [47335] (3 superfamilies)

29. a.29: Bromodomain-like [47363] (2 superfamilies)

30. a.30: ROP-like [47379] (2 superfamilies)

31. a.31: Dimerization-anchoring domain of cAMP-dependent type II PK regulatory subunit [47390] (1 superfamily)

32. a.32: Transcription factor IIA (TFIIA), N-terminal domain [47395] (1 superfamily)

33. a.33: Ectatomin, A & B chains [47400] (1 superfamily)

34. a.34: SinR repressor dimerisation domain-like [47405] (1 superfamily)

35. a.35: lambda repressor-like DNA-binding domains [47412] (1 superfamily)

36. a.36: Signal peptide-binding domain [47445] (1 superfamily)

37. a.37: Binding domain of Skn-1 [47453] (1 superfamily)

38. a.38: Helix-loop-helix DNA-binding domain [47458] (1 superfamily)

39. a.39: EF Hand-like [47472] (3 superfamilies)

40. a.40: Calponin-homology domain, CH-domain [47575] (1 superfamily)

41. a.41: Domain of poly(ADP-ribose) polymerase [47586] (1 superfamily)

42. a.42: MDM2 [47591] (1 superfamily)

43. a.43: Met repressor-like [47597] (1 superfamily)

44. a.44: Disulphide-bond formation facilitator (DSBA), insertion domain [47609] (1 superfamily)

45. a.45: Glutathione S-transferases, C-terminal domain [47615] (1 superfamily)

46. a.46: Methionine synthase domain-like [47643] (2 superfamilies)

47. a.47: STAT-like [47654] (2 superfamilies)

48. a.48: N-cbl like [47667] (3 superfamilies)

49. a.49: C-terminal domain B transposition protein [47680] (1 superfamily)

50. a.50: Anaphylotoxins (complement system) [47685] (1 superfamily)

51. a.51: Cytochrome c oxidase subunit h [47693] (1 superfamily)

52. a.52: Bifunctional inhibitor/lipid-transfer protein/seed storage 2S albumin [47698] (1 superfamily)

53. a.53: p53 tetramerization domain [47718] (1 superfamily)

54. a.54: Domain of early E2A DNA-binding protein, ADDBP [47723] (1 superfamily)

55. a.55: IHF-like DNA-binding proteins [47728] (1 superfamily)

56. a.56: CO dehydrogenase ISP C-domain like [47740] (1 superfamily)

57. a.57: Protein HNS-dependent expression A; HdeA [47751] (1 superfamily)

58. a.58: Chemotaxis receptor methyltransferase CheR, N-terminal domain [47756] (1 superfamily)

59. a.59: PAH2 domain [47761] (1 superfamily)

60. a.60: SAM domain-like [47768] (10 superfamilies)

61. a.61: Retroviral matrix proteins [47835] (1 superfamily)

62. a.62: Hepatitis B viral capsid (hbcag) [47851] (1 superfamily)

63. a.63: Apolipophorin-III [47856] (1 superfamily)

64. a.64: Saposin-like [47861] (2 superfamilies)

65. a.65: Annexin [47873] (1 superfamily)

66. a.66: Transducin (alpha subunit), insertion domain [47894] (1 superfamily)

67. a.68: Wiscott-Aldrich syndrome protein, WASP, C-terminal domain [47911] (1 superfamily)

68. a.69: Left-handed superhelix [47916] (2 superfamilies)

69. a.70: N-terminal domain of the delta subunit of the F1F0-ATP synthase [47927] (1 superfamily)

70. a.71: Endoplasmic reticulum protein ERP29, C-domain [47932] (1 superfamily)

71. a.72: Functional domain of the splicing factor Prp18 [47937] (1 superfamily)

72. a.73: Retrovirus capsid protein, N-terminal core domain [47942] (1 superfamily)

73. a.74: Cyclin-like [47953] (1 superfamily)

74. a.75: Ribosomal protein S7 [47972] (1 superfamily)

75. a.76: Iron-dependent represor protein, dimerization domain [47978] (1 superfamily)

76. a.77: DEATH domain [47985] (1 superfamily)

77. a.78: Fatty acid responsive transcription factor FadR, C-terminal domain [48007] (1 superfamily)

78. a.79: Antitermination factor NusB [48012] (1 superfamily)

79. a.80: DNA polymerase III clamp loader subunits, C-terminal domain [48018] (1 superfamily)

80. a.81: N-terminal domain of DnaB helicase [48023] (1 superfamily)

81. a.82: FliG C-terminal domain [48028] (1 superfamily)

82. a.83: Guanido kinases [48033] (1 superfamily)

83. a.84: Scaffolding protein gpD of bacteriophage procapsid [48044] (1 superfamily)

84. a.85: Hemocyanin, N-terminal domain [48049] (1 superfamily)

85. a.86: Di-copper centre-containing domain [48055] (1 superfamily)

86. a.87: DBL homology domain [48064] (1 superfamily)

87. a.88: LigA subunit of an aromatic-ring-opening dioxygenase LigAB [48075] (1 superfamily)

88. a.89: Methyl-coenzyme M reductase alpha and beta chain C-terminal domain [48080] (1 superfamily)

89. a.90: Transcription factor STAT-4 N-domain [48091] (1 superfamily)

90. a.91: Regulator of G-protein signalling, RGS [48096] (1 superfamily)

91. a.92: Carbamoyl phosphate synthetase, large subunit connection domain [48107] (1 superfamily)

92. a.93: Heme-dependent peroxidases [48112] (1 superfamily)

93. a.94: Ribosomal protein L19 (L19e) [48139] (1 superfamily)

94. a.95: Influenza virus matrix protein M1 [48144] (1 superfamily)

95. a.96: DNA-glycosylase [48149] (1 superfamily)

96. a.97: Anticodon-binding (C-terminal) domain of glutamyl-tRNA synthetase (GluRS) [48162] (1 superfamily)

97. a.98: R1 subunit of ribonucleotide reductase, N-terminal domain [48167] (1 superfamily)

98. a.99: FAD-binding (C-terminal) domain of DNA photolyase [48172] (1 superfamily)

99. a.100: 6-phosphogluconate dehydrogenase C-terminal domain-like [48178] (1 superfamily)

100. a.101: Uteroglobin-like [48200] (1 superfamily)

101. a.102: alpha/alpha toroid [48207] (4 superfamilies)

102. a.103: Citrate synthase [48255] (1 superfamily)

103. a.104: Cytochrome P450 [48263] (1 superfamily)

104. a.105: FIS-like [48282] (1 superfamily)

105. a.107: Trp repressor [48294] (1 superfamily)

106. a.108: Ribosomal protein L7/12, oligomerisation (N-terminal) domain [48299] (1 superfamily)

107. a.109: MHC class II-associated invariant chain ectoplasmic trimerization domain [48304] (1 superfamily)

108. a.110: Aldehyde ferredoxin oxidoreductase, C-terminal domains [48309] (1 superfamily)

109. a.111: Acid phosphatase/Vanadium-dependent haloperoxidase [48316] (1 superfamily)

110. a.112: sigma70 subunit fragment from RNA polymerase [48328] (1 superfamily)

111. a.113: DNA repair protein MutS, domain III [48333] (1 superfamily)

112. a.114: Interferon-induced guanylate-binding protein 1 (GBP1), C-terminal domain [48339] (1 superfamily)

113. a.115: A virus capsid protein alpha-helical domain [48344] (1 superfamily)

114. a.116: GTPase activation domain, GAP [48349] (1 superfamily)

115. a.117: Ras GEF [48365] (1 superfamily)

116. a.118: alpha-alpha superhelix [48370] (11 superfamilies)

117. a.119: Lipoxigenase [48483] (1 superfamily)

118. a.120: gene 59 helicase assembly protein [48492] (1 superfamily)

119. a.121: Tetracyclin repressor (Tet-repressor, TetR), C-terminal domain [48497] (1 superfamily)

120. a.122: Skp1-Skp2 dimerisation domains [48502] (1 superfamily)

121. a.123: Nuclear receptor ligand-binding domain [48507] (1 superfamily)

122. a.124: Phospholipase C/P1 nuclease [48536] (1 superfamily)

123. a.125: Catalytic domain of cyclic nucleotide phosphodiesterase 4b2b [48546] (1 superfamily)

124. a.126: Serum albumin [48551] (1 superfamily)

125. a.127: L-aspartase-like [48556] (1 superfamily)

126. a.128: Terpenoid synthases [48575] (1 superfamily)

127. a.129: GroEL-like chaperones, ATPase domain [48591] (1 superfamily)

128. a.130: Chorismate mutase II [48599] (1 superfamily)

129. a.131: Peridinin-chlorophyll protein [48607] (1 superfamily)

130. a.132: Heme oxygenase [48612] (1 superfamily)

131. a.133: Phospholipase A2, PLA2 [48618] (1 superfamily)

132. a.134: Fungal elicitin, plant patogen [48646] (1 superfamily)

133. a.135: Tetraspanin [48651] (1 superfamily)

134. a.136: Repressor of bacterial conjugation FinO [48656] (1 superfamily)

135. a.137: Non-globular all-alpha subunits of globular proteins [48661] (8 superfamilies)

136. a.138: Multiheme cytochromes [48694] (1 superfamily)

137. a.139: Type I dockerin domain [63445] (1 superfamily)

138. a.140: LEM domain [63450] (1 superfamily)

139. a.141: Frizzled cystein-rich domain [63500] (1 superfamily)

140. a.142: PTS-regulatory domain, PRD [63519] (1 superfamily)

141. a.143: RNA polymerase omega subunit [63561] (1 superfamily)

142. a.144: PABC (PABP) domain [63569] (1 superfamily)

143. a.145: Flagellar transcriptional activator FlhD [63591] (1 superfamily)

144. a.146: Telomeric repeat binding factor (TRF) dimerisation domain [63599] (1 superfamily)

More info for Class a: All alpha proteins

Timeline for Class a: All alpha proteins:

• Class a: All alpha proteins first appeared (with stable ids) in SCOP 1.55
  
• Class a: All alpha proteins appears in SCOP 1.59
  
• Class a: All alpha proteins appears in the current release, SCOPe 2.08