- Root: SCOP 1.65
Class c: Alpha and beta proteins (a/b) [51349] (121 folds)

c.1: TIM beta/alpha-barrel [51350] (26 superfamilies)

*contains parallel beta-sheet barrel, closed; n=8, S=8; strand order 12345678*

the first seven superfamilies have similar phosphate-binding sitesc.2: NAD(P)-binding Rossmann-fold domains [51734] (1 superfamily)

*core: 3 layers, a/b/a; parallel beta-sheet of 6 strands, order 321456*

The nucleotide-binding modes of this and the next two folds/superfamilies are similarc.3: FAD/NAD(P)-binding domain [51904] (1 superfamily)

*core: 3 layers, b/b/a; central parallel beta-sheet of 5 strands, order 32145; top antiparallel beta-sheet of 3 strands, meander*c.4: Nucleotide-binding domain [51970] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32145; Rossmann-like*c.5: MurCD N-terminal domain [51983] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32145; incomplete Rossmann-like fold; binds UDP group*c.6: 7-stranded beta/alpha barrel [51988] (3 superfamilies)

*variant of beta/alpha barrel; parallel beta-sheet barrel, closed, n=7, S=8; strand order 1234567; some members may have fewer strands*c.7: PFL-like glycyl radical enzymes [51997] (1 superfamily)

*contains: barrel, closed; n=10, S=10; accommodates a hairpin loop inside the barrel*c.8: The "swivelling" beta/beta/alpha domain [52008] (7 superfamilies)

*3 layers: b/b/a; the central sheet is parallel, and the other one is antiparallel; there are some variations in topology*

this domain is thought to be mobile in all proteins known to contain itc.9: Barstar-like [52037] (2 superfamilies)

*2 layers, a/b; parallel beta-sheet of 3 strands, order 123*c.10: Leucine-rich repeat, LRR (right-handed beta-alpha superhelix) [52046] (2 superfamilies)

*2 curved layers, a/b; parallel beta-sheet; order 1234...N*c.11: Outer arm dynein light chain 1 [52074] (1 superfamily)

*(beta-beta-alpha)n superhelix*c.12: Ribosomal proteins L15p and L18e [52079] (1 superfamily)

*core: three turns of irregular (beta-beta-alpha)n superhelix*c.13: SpoIIaa-like [52086] (2 superfamilies)

*core: 4 turns of a (beta-alpha)n superhelix*c.14: ClpP/crotonase [52095] (1 superfamily)

*core: 4 turns of (beta-beta-alpha)n superhelix*c.15: BRCT domain [52112] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 2134*c.16: Lumazine synthase [52120] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 2134*c.17: Caspase-like [52128] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 2134*c.18: DNA glycosylase [52140] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 2134*c.19: FabD/lysophospholipase-like [52150] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 6 strands, order 432156; strand 4 is antiparallel to the rest*c.20: Initiation factor IF2/eIF5b, domain 3 [52155] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 2134*c.21: Ribosomal protein L13 [52160] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 3214*c.22: Ribosomal protein L4 [52165] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 4 strands, order 1423*c.23: Flavodoxin-like [52171] (16 superfamilies)

*3 layers, a/b/a; parallel beta-sheet of 5 strand, order 21345*c.24: Methylglyoxal synthase-like [52334] (1 superfamily)

*3 layers, a/b/a; parallel beta-sheet of 5 strands, order 32145*c.25: Ferredoxin reductase-like, C-terminal NADP-linked domain [52342] (1 superfamily)

*3 layers, a/b/a; parallel beta-sheet of 5 strands, order 32145*c.26: Adenine nucleotide alpha hydrolase-like [52373] (3 superfamilies)

*core: 3 layers, a/b/a ; parallel beta-sheet of 5 strands, order 32145*c.27: Nucleoside phosphorylase/phosphoribosyltransferase catalytic domain [52417] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32145; Rossmann-like*c.28: Cryptochrome/photolyase, N-terminal domain [52424] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32145; Rossmann-like*c.30: PreATP-grasp domain [52439] (1 superfamily)

*3 layers: a/b/a; parallel or mixed beta-sheet of 4 to 6 strands*

possible rudiment form of Rossmann-fold domainc.31: DHS-like NAD/FAD-binding domain [52466] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456; Rossmann-like*c.32: Tubulin/Dihydroxyacetone kinase nucleotide-binding domain [52489] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.33: Cysteine hydrolase [52498] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.34: DFP DNA/pantothenate metabolism flavoprotein [52506] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.35: Phosphosugar isomerase [52511] (1 superfamily)

*core: 3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.36: Thiamin diphosphate-binding fold (THDP-binding) [52517] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 213465*c.37: P-loop containing nucleoside triphosphate hydrolases [52539] (1 superfamily)

*3 layers: a/b/a, parallel or mixed beta-sheets of variable sizes*c.38: PTS IIb component [52727] (1 superfamily)

*3 layers: a/b/a, parallel beta-sheet of 6 strands, order 324156*c.39: Nicotinate mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) [52732] (1 superfamily)

*3 layers: a/b/a, parallel beta-sheet of 7 strands, order 3214567*c.40: Methylesterase CheB, C-terminal domain [52737] (1 superfamily)

*3 layers: a/b/a, parallel beta-sheet of 7 strands, order 3421567*c.41: Subtilisin-like [52742] (1 superfamily)

*3 layers: a/b/a, parallel beta-sheet of 7 strands, order 2314567; left-handed crossover connection between strands 2 & 3*c.42: Arginase/deacetylase [52767] (1 superfamily)

*3 layers: a/b/a, parallel beta-sheet of 8 strands, order 21387456*c.43: CoA-dependent acyltransferases [52776] (1 superfamily)

*core: 2 layers, a/b; mixed beta-sheet of 6 strands, order 324561; strands 3 & 6 are antiparallel to the rest*c.44: Phosphotyrosine protein phosphatases I-like [52787] (2 superfamilies)

*3 layers: a/b/a; parallel beta-sheet of 4 strands, order 2134*c.45: (Phosphotyrosine protein) phosphatases II [52798] (1 superfamily)

*core: 3 layers, a/b/a; parallel beta-sheet of 4 strands, order 1432*c.46: Rhodanese/Cell cycle control phosphatase [52820] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32451*c.47: Thioredoxin fold [52832] (2 superfamilies)

*core: 3 layers, a/b/a; mixed beta-sheet of 4 strands, order 4312; strand 3 is antiparallel to the rest*c.48: TK C-terminal domain-like [52921] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 5 strands, order 13245, strand 1 is antiparallel to the rest*c.49: Pyruvate kinase C-terminal domain-like [52934] (2 superfamilies)

*3 layers: a/b/a; mixed beta-sheet of 5 strands, order 32145, strand 5 is antiparallel to the rest*c.50: Macro domain-like [52948] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of of 6 strands, order 165243, strand 3 is antiparallel to the rest*c.51: Anticodon-binding domain-like [52953] (4 superfamilies)

*3 layers: a/b/a; mixed beta-sheet of five strands, order 21345; strand 4 is antiparallel to the rest*c.52: Restriction endonuclease-like [52979] (3 superfamilies)

*core: 3 layers, a/b/a; mixed beta-sheet of 5 strands, order 12345; strands 2 &, in some families, 5 are antiparallel to the rest*c.53: Resolvase-like [53040] (2 superfamilies)

*Core: 3 layers: a/b/a; mixed beta-sheet of 5 strands, order 21345; strand 5 is antiparallel to the rest*c.54: IIA domain of mannose transporter, IIA-Man [53061] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 5 strands, order 21345; strand 5 is antiparallel to the rest*c.55: Ribonuclease H-like motif [53066] (7 superfamilies)

*3 layers: a/b/a; mixed beta-sheet of 5 strands, order 32145; strand 2 is antiparallel to the rest*c.56: Phosphorylase/hydrolase-like [53162] (6 superfamilies)

*core: 3 layers, a/b/a ; mixed sheet of 5 strands: order 21354; strand 4 is antiparallel to the rest; contains crossover loops*c.57: Molybdenum cofactor biosynthesis proteins [53217] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 5 strands; order: 21354, strand 5 is antiparallel to the rest; permutation of the Phosphorylase/hydrolase-like fold*c.58: Aminoacid dehydrogenase-like, N-terminal domain [53222] (1 superfamily)

*core: 3 layers: a/b/a; parallel beta-sheet of 4 strands; 2134*c.59: MurD-like peptide ligases, peptide-binding domain [53243] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 6 strands, order 126345; strand 1 is antiparallel to the rest*c.60: Phosphoglycerate mutase-like [53253] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 6 strands, order 324156; strand 5 is antiparallel to the rest*c.61: PRTase-like [53270] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 6 strands, order 321456; strand 3 is antiparallel to the rest*c.62: vWA-like [53299] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 6 strands, order 321456; strand 3 is antiparallel to the rest*c.63: CoA transferase [53315] (1 superfamily)

*core: 3 layers: a/b/a; beta-sheet of 7 strands, order 4321567; part of sheet is folded upon itself and forms a barrel-like structure*c.64: Pyruvate-ferredoxin oxidoreductase, PFOR, domain III [53322] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 6 strands, order 231456; strand 3 is antiparallel to the rest*c.65: Formyltransferase [53327] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 7 strands, order 3214567; strand 6 is antiparallel to the rest*c.66: S-adenosyl-L-methionine-dependent methyltransferases [53334] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 7 strands, order 3214576; strand 7 is antiparallel to the rest*c.67: PLP-dependent transferases [53382] (1 superfamily)

*main domain: 3 layers: a/b/a, mixed beta-sheet of 7 strands, order 3245671; strand 7 is antiparallel to the rest*c.68: Nucleotide-diphospho-sugar transferases [53447] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 7 strands, order 3214657; strand 6 is antiparallel to the rest*c.69: alpha/beta-Hydrolases [53473] (1 superfamily)

*core: 3 layers, a/b/a; mixed beta-sheet of 8 strands, order 12435678, strand 2 is antiparallel to the rest*c.70: Nucleoside hydrolase [53589] (1 superfamily)

*core: 3 layers, a/b/a ; mixed beta-sheet of 8 strands, order 32145687; strand 7 is antiparallel to the rest*c.71: Dihydrofolate reductases [53596] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 8 strands, order 34251687; strand 8 is antiparallel to the rest*c.72: Ribokinase-like [53612] (2 superfamilies)

*core: 3 layers: a/b/a; mixed beta-sheet of 8 strands, order 21345678, strand 7 is antiparallel to the rest*

potential superfamily: members of this fold have similar functions but different ATP-binding sitesc.73: Carbamate kinase-like [53632] (1 superfamily)

*3 layers: a/b/a; mixed (mainly parallel) beta-sheet of 8 strands, order 34215786; strand 8 is antiparallel to the rest*c.74: AraD-like aldolase/epimerase [53638] (1 superfamily)

*3 layers: a/b/a; mixed (mostly antiparallel) beta-sheet of 9 strands, order 432159876; left-handed crossover between strands 4 and 5*c.76: Alkaline phosphatase-like [53648] (1 superfamily)

*core:3 layers: a/b/a; mixed beta-sheet of 8 strands, order 43516728, strand 7 is antiparallel to the rest*c.77: Isocitrate/Isopropylmalate dehydrogenases [53658] (1 superfamily)

*consists of two intertwined (sub)domains related by pseudo dyad; duplication*

3 layers: a/b/a; single mixed beta-sheet of 10 strands, order 213A945867 (A=10); strands from 5 to 9 are antiparallel to the restc.78: ATC-like [53670] (2 superfamilies)

*consists of two similar domains related by pseudo dyad; duplication*

core: 3 layers, a/b/a, parallel beta-sheet of 4 strands, order 2134c.79: Tryptophan synthase beta subunit-like PLP-dependent enzymes [53685] (1 superfamily)

*consists of two similar domains related by pseudo dyad; duplication*

core: 3 layers, a/b/a; parallel beta-sheet of 4 strands, order 3214c.80: SIS domain [53696] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 5 strands, order 21345*c.81: Formate dehydrogenase/DMSO reductase, domains 1-3 [53705] (1 superfamily)

*contains of two similar intertwined domains related by pseudo dyad; duplication*

core: 3 layers: a/b/a; parallel beta-sheet of 5 strands, order 32451c.82: ALDH-like [53719] (1 superfamily)

*consists of two similar domains with 3 layers (a/b/a) each; duplication*

core: parallel beta-sheet of 5 strands, order 32145c.83: Aconitase iron-sulfur domain [53731] (1 superfamily)

*consists of three similar domains with 3 layers (a/b/a) each; duplication*

core: parallel beta-sheet of 5 strands, order 32145c.84: Phosphoglucomutase, first 3 domains [53737] (1 superfamily)

*consists of three similar domains with 3 layers (a/b/a) each; duplication*

core: mixed beta-sheet of 4 strands, order 2134, strand 4 is antiparallel to the restc.85: L-fucose isomerase, N-terminal and second domains [53742] (1 superfamily)

*consists of two domains of similar topology, 3 layers (a/b/a) each*

Domain 1 (1-173) has parallel beta-sheet of 5 strands, order 21345

Domain 2 (174-355) has parallel beta-sheet of 4 strands, order 2134c.86: Phosphoglycerate kinase [53747] (1 superfamily)

*consists of two non-similar domains, 3 layers (a/b/a) each*

Domain 1 has parallel beta-sheet of 6 strands, order 342156

Domain 2 has parallel beta-sheet of 6 strands, order 321456c.87: UDP-Glycosyltransferase/glycogen phosphorylase [53755] (1 superfamily)

*consists of two non-similar domains with 3 layers (a/b/a) each*

domain 1: parallel beta-sheet of 7 strands, order 3214567

domain 2: parallel beta-sheet of 6 strands, order 321456c.88: Glutaminase/Asparaginase [53773] (1 superfamily)

*consists of two non-similar alpha/beta domains, 3 layers (a/b/a) each*

Domain 1 has mixed beta-sheet of 6 strands, order 213456, strand 6 is antiparallel to the rest; left-handed crossover connection between strands 4 and 5

Domain 2 has parallel beta-sheet of 4 strands, order 1234c.89: Phosphofructokinase [53783] (1 superfamily)

*consists of two non-similar domains, 3 layers (a/b/a) each*

Domain 1 has mixed sheet of 7 strands, order 3214567; strands 3 & 7 are antiparallel to the rest

Domain 2 has parallel sheet of 4 strands, order 2314c.90: Cobalt precorrin-4 methyltransferase CbiF [53789] (1 superfamily)

*consists of two non-similar domains*

Domain 1 has parallel sheet of 5 strands, order 32415

Domain 2 has mixed sheet of 5 strands, order 12534; strands 4 & 5 are antiparallel to the restc.91: PEP carboxykinase-like [53794] (1 superfamily)

*contains a P-loop NTP-binding motif; mixed beta-sheet folds into a barrel-like structure with helices packed on one side*c.92: Chelatase-like [53799] (2 superfamilies)

*duplication: tandem repeat of two domains; 3 layers (a/b/a); parallel beta-sheet of 4 strands, order 2134*c.93: Periplasmic binding protein-like I [53821] (1 superfamily)

*consists of two similar intertwined domain with 3 layers (a/b/a) each: duplication*

parallel beta-sheet of 6 strands, order 213456c.94: Periplasmic binding protein-like II [53849] (1 superfamily)

*consists of two similar intertwined domain with 3 layers (a/b/a) each: duplication*

mixed beta-sheet of 5 strands, order 21354; strand 5 is antiparallel to the restc.95: Thiolase-like [53900] (1 superfamily)

*consists of two similar domains related by pseudo dyad; duplication*

3 layers: a/b/a; mixed beta-sheet of 5 strands, order 32451; strands 1 & 5 are antiparallel to the restc.96: Fe-only hydrogenase [53919] (1 superfamily)

*consist of two intertwined domains; contains partial duplication*c.97: Cytidine deaminase-like [53926] (2 superfamilies)

*core: alpha-beta(2)-(alpha-beta)2; 3 layers (a/b/a); mixed beta-sheet of 4 strands, order 2134; strand 2 is antiparallel to the rest*c.98: MurF and HprK N-domain-like [63417] (2 superfamilies)

*core: 3 layers, a/b/a; parallel beta-sheet of 4 strands, order 1234; structural similarity of the MurF and HprK extends beyond the core.*c.99: Dipeptide transport protein [63991] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456; also contains a C-terminal alpha+beta subdomain*c.100: Thiamin pyrophosphokinase, catalytic domain [63998] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 432156*c.101: Undecaprenyl diphosphate synthase [64004] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 342156*c.102: Cell-division inhibitor MinC, N-terminal domain [64042] (1 superfamily)

*beta(2)-(alpha-beta)2-beta; 2 layers, a/b; mixed beta-sheet of 5 strands, order 12345; strands 1 & 5 are antiparallel to the rest*c.103: Hypothetical protein MT938 (MTH938) [64075] (1 superfamily)

*core: 3 layers, b+a/b/a ; the central mixed sheet of 5 strands: order 21534; strand 2 is antiparallel to the rest*c.104: YjeF N-terminal domain-like [64152] (1 superfamily)

*3 layers: a/b/a; mixed (mainly parallel) beta-sheet of 8 strands, order 32145678; strand 8 is antiparallel to the rest*c.105: 2,3-Bisphosphoglycerate-independent phosphoglycerate mutase, substrate-binding domain [64157] (1 superfamily)

*core:3 layers: a/b/a; mixed beta-sheet of 8 strands, order 45321678, strands 4 and 5 are antiparallel to the rest*c.106: SurE-like [64166] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 9 strands, order 342156798; strands 3, 8 and 9 are antiparallel to the rest; left-handed crossover connection between strands 6 and 7*c.107: DHH phosphoesterases [64181] (1 superfamily)

*consists of two non-similar domains*

Domain 1 has parallel sheet of 6 strands, order 321456

Domain 2 has mixed sheet of 5 strands, order 12345; strands 1 & 4 are antiparallel to the restc.108: HAD-like [56783] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.109: PEP carboxykinase N-terminal domain [68922] (1 superfamily)

*contains mixed beta-sheets; topology is partly similar to that of the catalytic C-terminal domain*c.110: D-Tyr tRNAtyr deacylase, DTD [69499] (1 superfamily)

*beta(2)-(alpha-beta)2-beta(3); 3 layers, a/b/b; some topological similarity to the N-terminal domain of MinC*c.111: Activating enzymes of the ubiquitin-like proteins [69571] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 8 strands, order 32145678; strands 6 and 8 are antiparallel to the rest*c.112: Glycerol-3-phosphate (1)-acyltransferase [69592] (1 superfamily)

*3 layers: a/b/a; mixed beta-sheet of 9 strands, order 918736452; strands 1, 2 and 8 are antiparallel to the rest*c.113: Uroporphyrinogen III synthase (U3S, HemD) [69617] (1 superfamily)

*duplication: consists of two similar 'swapped' domain with 3 layers (a/b/a) each; parallel beta-sheet of 5 strands, order 21345*c.114: YchN-like [75168] (1 superfamily)

*3 layers: a/b/a, core: parallel beta-sheet of 5 strands, order 43215*c.115: Hypothetical protein MTH777 (MT0777) [75180] (1 superfamily)

*3 layers: a/b/a; parallel beta-sheet of 6 strands, order 321456*c.116: alpha/beta knot [75216] (1 superfamily)

*core: 3 layers: a/b/a, parallel beta-sheet of 5 strands, order 21435; contains a deep trefoil knot*c.117: Amidase signature (AS) enzymes [75303] (1 superfamily)

*possible duplication: the topologies of N- and C-terminal halves are similar; 3 layers: a/b/a; single mixed beta-sheet of 10 strands, order 213549A867 (A=10); strands from 5 to 9 are antiparallel to the rest*c.118: GckA/TtuD-like [82543] (1 superfamily)

*consists of two non-similar domains*

Domain 1 has parallel sheet of 6 strands, order 321456, Rossmann-like topology

Domain 2 has mixed sheet of 6 strands, order 126345; strands 5 and 6 are antiparallel to the rest; some similarity to CbiF Domain 2c.119: DegV-like [82548] (1 superfamily)

*consists of two non-similar domains*

Domain 1 has parallel sheet of 5 strands, order 21345, and antiparallel 3-stranded sheet, 132

Domain 2 has mixed sheet of 6 strands, order 321645; strands 2 and 6 are antiparallel to the restc.120: PIN domain-like [88722] (1 superfamily)

*3 layers, a/b/a; core: parallel beta-sheet of 5 strands, order 32145*c.121: Ribose/Galactose isomerase RpiB/AlsB [89622] (1 superfamily)

*3 layers: a/b/a, core: parallel beta-sheet of 5 strands, order 21354; topological similarity to a part of the arginase/deacetylase fold*c.122: Archaeal malate dehydrogenase-like [89732] (1 superfamily)

*core: 3 layers, a/b/a; mixed sheet of 7 strands, order 1237456; strands 1, 6 and 7 are antiparallel to the rest*c.123: CoA-transferase family III (CaiB/BaiF) [89795] (1 superfamily)

*consist of two different alpha/beta domains; N-terminal domain has a SurE-like topology with a left-handed beta-alpha-beta unit*

**Timeline for Class c: Alpha and beta proteins (a/b)**:

- Class c: Alpha and beta proteins (a/b) first appeared (with stable ids) in SCOP 1.55

- Class c: Alpha and beta proteins (a/b) appears in SCOP 1.63

- Class c: Alpha and beta proteins (a/b) appears in SCOP 1.67

- Class c: Alpha and beta proteins (a/b) appears in the current release, SCOPe 2.08