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
![](/ecod/img/p.gif)
Refs: Structure 14, 1489-1498; Current opinion in structural biology 18, 358-365
![](/ecod/img/m.gif)
![](/ecod/img/m.gif)
![](/ecod/img/p.gif)
54123, 3-crossover-4
![](/ecod/img/m.gif)
Representatives:
e3psiA7[A:1114-1210]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
TRANSCRIPTION ELONGATION FACTOR SPT6 ; X-RAY DIFFRACTION 3.3Å
e7o6bA1[A:1114-1211] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e8of0S7[S:1145-1175,S:1226-1282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8oeuS7[S:1145-1175,S:1226-1288] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e6gmhM6[M:1145-1176,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6,Transcription elongation factor SPT6,Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e6tedM3[M:1145-1176,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e7opcM7[M:1145-1175,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e7oopM7[M:1145-1175,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e7opdM7[M:1145-1175,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e7uncM9[M:1145-1176,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e7undM7[M:1145-1176,M:1226-1287] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription elongation factor SPT6 ; ELECTRON MICROSCOPY
e8oevS6[S:1145-1175,S:1226-1288] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; 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.
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
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