Evolutionary classification of protein domain structures
alpha arraysalpha-helix arrays with mainly perpendicular helices
alpha bundlesalpha-helix bundles with mainly parallel helices
alpha superhelicesrepeating alpha-helix hairpins form a superhelix
alpha duplicates or obligate multimersalpha duplicates or monomers associate together to form a compact domain
alpha complex topologyalpha domain with complex and unique topology that cannot be described as array or bundle or superhelix
beta barrelssingle beta-sheet folded upon itself to form a barrel
beta meanderssingle beta-sheet with mainly meander topology
beta sandwichestwo beta-sheets stacked together to form a sandwich
beta duplicates or obligate multimersbeta duplicates or monomers associate together to form a compact domain
beta complex topologybeta domains with complex and unique topology that cannot be described as barrel or sandwich or meander
a+b two layersone alpha-helix layer and one beta-sheet layer
a+b three layersone mainly antiparallel beta-sheet layer sandwiched between two alpha-helix layers
a+b four layerstwo beta-sheet layers sandwiched between two alpha-helix layers
a+b complex topologyalpha and beta domain with complex and unique topology that cannot be described in layers
a+b duplicates or obligate multimersalpha and beta duplicates or monomers associated together to form a compact domain
a/b barrelsrepeating beta-alpha units form a barrel
a/b three-layered sandwichesrepeating beta-alpha units form a sandwich with a mainly parallel beta-sheet layer stacked between two alpha-helix layers
X: Rossmann-like
H: Rossmann-related
T: FAD/NAD(P)-binding domain
F: Unmapped domains
Pseudo group of domains that do not map to PFam family profiles. Domains inside should not be considered as in one family.
Representatives:
e1lqtA1[A:109-324]
nonrep
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FprA ; ligands: ACT,FAD,ODP ; X-RAY DIFFRACTION 1.05Å
e6gnaA1[A:114-217]
* nonrep
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Thioredoxin reductase ; ligands: ACT,PEG,PGE ; X-RAY DIFFRACTION 1.295Å
e1gteA4[A:288-440]
nonrep
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DIHYDROPYRIMIDINE DEHYDROGENASE ; ligands: FAD ; X-RAY DIFFRACTION 1.650Å
e2yr4B1[B:1-474,B:615-704]
nonrep
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Pro-enzyme of L-phenylalanine oxidase ; ligands: FAD,SO4 ; X-RAY DIFFRACTION 1.70Å
e4mifB1[B:13-383,B:557-617]
nonrep
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Pyranose 2-oxidase ; ligands: FDA,MG ; X-RAY DIFFRACTION 1.80Å
e7z4xA2[A:2-167,A:273-388]
* nonrep
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Putative dehydrogenase/oxygenase subunit (Flavoprotein) ; ligands: FAD ; X-RAY DIFFRACTION 2.050Å
e7v50A2[A:5-145,A:381-532]
* nonrep
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Putative flavin-binding monooxygenase ; ligands: FAD,NAP ; X-RAY DIFFRACTION 2.070Å
e2gv8A2[A:181-287]
nonrep
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monooxygenase ; ligands: GOL,NDP ; X-RAY DIFFRACTION 2.1Å
e3t2zA2[A:116-263]
nonrep
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Sulfide-quinone reductase, putative ; ligands: FAD,H2S,S3H,SO4 ; X-RAY DIFFRACTION 2.299Å
e3c4aA1[A:1-151,A:257-371]
* nonrep
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Probable tryptophan hydroxylase vioD ; ligands: FAD ; X-RAY DIFFRACTION 2.30Å
mixed a+b and a/balpha and beta domain consists of both a+b and a/b regions
few secondary structure elementsstabilized by cofactors or disulfides
extended segmentsextended, non-globular segments, frequently bind to other proteins to form complexes