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
![](/ecod/img/m.gif)
![](/ecod/img/m.gif)
![](/ecod/img/m.gif)
![](/ecod/img/m.gif)
Representatives:
e5hzrA2[A:791-1009,A:1053-1128]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
SNF2-family ATP dependent chromatin remodeling factor like protein ; ligands: KH2,SO4 ; X-RAY DIFFRACTION 2.3Å
e1z3iX1[X:390-735]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
similar to RAD54-like ; ligands: SO4,ZN ; X-RAY DIFFRACTION 3.000Å
e5jxtC1[C:408-734] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtB1[B:407-734] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtF1[F:407-734] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtN1[N:408-731] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtO1[O:408-731] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtP1[P:408-731] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtH1[H:408-732] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e5jxtA1[A:407-733] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; X-RAY DIFFRACTION 3.0Å
e7oobb2[b:754-1011,b:1383-1399] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ligands: ADP,BEF,MG ; ELECTRON MICROSCOPY
e7oopb2[b:754-1025,b:1383-1399] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e7opcb2[b:754-1011,b:1383-1399] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e7opdb2[b:754-1011,b:1383-1399] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
![](/ecod/img/p.gif)
Pseudo group of domains that do not map to PFam family profiles. Domains inside should not be considered as in one family.
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