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




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
e5x0xO2[O:1004-1223,O:1248-1251,O:1277-1327,O:1336-1349] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription regulatory protein SNF2 ; ELECTRON MICROSCOPY
e5vvrM1[M:579-797] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA repair and recombination protein RAD26 ; ELECTRON MICROSCOPY
e6irnK2[K:423-657] Image Pymol Jmol Links: PDB, SCOP, CATH
; ligands: ADP
e6k1pK2[K:423-657] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ISWI chromatin-remodeling complex ATPase ISW1 ; ligands: ADP,BEF ; ELECTRON MICROSCOPY
e6pwfK2[K:410-640] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
chromatin remodeling factor ISWI ; ELECTRON MICROSCOPY
e6kw3Y2[Y:707-927,Y:952-955,Y:975-1006] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Nuclear protein STH1/NPS1 ; ELECTRON MICROSCOPY
e6kw4Y1[Y:707-927,Y:952-955,Y:975-1006] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Nuclear protein STH1/NPS1 ; ELECTRON MICROSCOPY
e6ne3W2[W:406-634] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 5 ; ligands: ADP ; ELECTRON MICROSCOPY
e6kw5Q1[Q:707-927,Q:952-955,Q:975-1006] Image Pymol Jmol Links: PDB, SCOP, CATH
Nuclear protein STH1/NPS1 ; ELECTRON MICROSCOPY
e5z3vO1[O:1004-1223,O:1248-1251,O:1277-1317,O:1337-1349] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription regulatory protein SNF2 ; ligands: ADP,BEF ; ELECTRON MICROSCOPY
e7epuB1[B:271-493,B:513-599,B:640-656] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromodomain-helicase-DNA-binding protein 1-like ; X-RAY DIFFRACTION 3.500Å
e8he5O2[O:577-816] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8b3fb1[b:758-1025,b:1383-1399] Image Pymol Jmol Links: PDB, SCOP, CATH
; ELECTRON MICROSCOPY
e7x3tV2[V:422-657] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ISWI chromatin-remodeling complex ATPase ISW1 ; ligands: ADP,BEF ; ELECTRON MICROSCOPY
e6g0lM4[M:607-841,M:1006-1026] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Chromo domain-containing protein 1 ; ligands: ADP,BEF ; ELECTRON MICROSCOPY

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