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:
e5hzrA1[A:458-493,A:529-790]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
SNF2-family ATP dependent chromatin remodeling factor like protein ; ligands: KH2,NA,SO4 ; X-RAY DIFFRACTION 2.3Å
e5jxrA2[A:87-409] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; ligands: CL ; X-RAY DIFFRACTION 2.4Å
e5jxrB2[B:87-409] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromatin-remodeling complex ATPase-like protein ; ligands: CL ; X-RAY DIFFRACTION 2.4Å
e5x0xO1[O:670-690,O:743-1003] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription regulatory protein SNF2 ; ELECTRON MICROSCOPY
e6eg2A2[A:703-955] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Maltose/maltodextrin-binding periplasmic protein,Probable global transcription activator SNF2L2 ; ligands: IPA,J7J ; X-RAY DIFFRACTION 2.98Å
e7ennK2[K:28-270] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromodomain-helicase-DNA-binding protein 1-like ; ligands: ADP,BEF ; ELECTRON MICROSCOPY
e6iroL1[L:101-142,L:184-421] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ISWI chromatin-remodeling complex ATPase ISW1 ; ligands: ADP ; ELECTRON MICROSCOPY
e6irmK1[K:101-143,K:184-421] Image Pymol Jmol Links: PDB, SCOP, CATH
; ligands: ADP,BEF
e6jylK1[K:101-143,K:184-421] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ISWI chromatin-remodeling complex ATPase ISW1 ; ligands: ADP,BEF,MG ; ELECTRON MICROSCOPY
e7otqK2[K:42-270] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromodomain-helicase-DNA-binding protein 1-like ; ELECTRON MICROSCOPY
e7oo3b1[b:490-754] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e7oobb1[b:490-753] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ligands: ADP,BEF,MG ; ELECTRON MICROSCOPY
e7oopb1[b:490-753] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e7opcb1[b:490-753] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e7opdb1[b:490-753] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA excision repair protein ERCC-6 ; ELECTRON MICROSCOPY
e1z63A2[A:432-661]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
Helicase of the snf2/rad54 family ; X-RAY DIFFRACTION 3.0Å
e1z3iX2[X:92-389]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
similar to RAD54-like ; ligands: SO4 ; X-RAY DIFFRACTION 3.000Å
![](/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