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
X: TIM beta/alpha-barrel
H: TIM barrels
T: TIM barrels
F: Glyco_hydro_18
Representatives:
e1itxA2[A:33-337,A:410-451]
nonrep
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GLYCOSYL HYDROLASE ; ligands: GOL ; X-RAY DIFFRACTION 1.1Å
e1jndA2[A:2-278,A:371-420]
nonrep
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IMAGINAL DISC GROWTH FACTOR-2 ; ligands: MAN ; X-RAY DIFFRACTION 1.3Å
e1vf8A2[A:1-245,A:316-372]
nonrep
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SECRETORY PROTEIN ; X-RAY DIFFRACTION 1.31Å
e1goiA3[A:3-291,A:380-446]
nonrep
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CHITINASE B ; ligands: GOL,SO4 ; X-RAY DIFFRACTION 1.45Å
e1edqA3[A:133-443,A:517-563]
nonrep
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CHITINASE A ; X-RAY DIFFRACTION 1.55Å
e1cnvA1[A:1-283]
nonrep
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CONCANAVALIN B ; X-RAY DIFFRACTION 1.65Å
e1ta3A1[A:1-274]
nonrep
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XYLANASE INHIBITOR PROTEIN I ; ligands: EDO,NAG ; X-RAY DIFFRACTION 1.7Å
e1w9pA2[A:39-298,A:361-433]
nonrep
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CHITINASE ; ligands: SO4 ; X-RAY DIFFRACTION 1.7Å
e1kfwA2[A:10-327,A:389-444]
nonrep
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CHITINASE B ; ligands: GOL ; X-RAY DIFFRACTION 1.74Å
e4txgA1[A:107-463,A:581-643]
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Chitinase ; ligands: CS ; X-RAY DIFFRACTION 1.750Å
e1edtA1[A:6-270]
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ENDO-BETA-N-ACETYLGLUCOSAMINIDASE H, ENDO H ; X-RAY DIFFRACTION 1.9Å
e5gztB2[B:559-815,B:882-928]
nonrep
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Chitinase ; ligands: FMT ; X-RAY DIFFRACTION 2.10Å
e5gztB5[B:1044-1304,B:1373-1416]
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Chitinase ; ligands: FMT,PO4 ; X-RAY DIFFRACTION 2.10Å
e4tx8A2[A:75-396]
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Probable chitinase A ; ligands: CA,FLC,MG ; X-RAY DIFFRACTION 2.170Å
e3bxwB1[B:11-279,B:337-371]
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Chitinase domain-containing protein 1 ; ligands: SO4 ; X-RAY DIFFRACTION 2.700Å
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.
a/b three-layered sandwichesrepeating beta-alpha units form a sandwich with a mainly parallel beta-sheet layer stacked between two alpha-helix layers
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