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
![](/ecod/img/m.gif)
![](/ecod/img/p.gif)
![](/ecod/img/p.gif)
![](/ecod/img/m.gif)
Representatives:
Domain assembly:
e1nh2C1[C:228-286]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
Transcription initiation factor IIA large chain , X-RAY DIFFRACTION 1.9Å
e1nh2D1[D:55-121] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large chain , X-RAY DIFFRACTION 1.9Å
e1rm1C1[C:228-286] Image Pymol Jmol Links: PDB, SCOP, CATH
TRANSCRIPTION INITIATION FACTOR IIA LARGE CHAIN ; X-RAY DIFFRACTION 2.5Å
e5fmfM2[M:228-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RNA POLYMERASE II PRE-INITIATION COMPLEX, TOA1 ; ELECTRON MICROSCOPY
e5furC1[C:330-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TRANSCRIPTION INITIATION FACTOR IIA SUBUNIT 1 ; ELECTRON MICROSCOPY
e5iy6N1[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iy7N1[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iy8N1[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iy9N2[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iyaN2[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iybN1[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iycN2[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5iydN1[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e5fywU1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TRANSCRIPTION INITIATION FACTOR IIA LARGE SUBUNIT ; ELECTRON MICROSCOPY
e5fz5U1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TRANSCRIPTION INITIATION FACTOR IIA LARGE SUBUNIT ; ELECTRON MICROSCOPY
e5svad1[d:228-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e5m4sA1[A:158-210] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 2,Transcription initiation factor IIA subunit 1,Transcription initiation factor IIA subunit 1 ; X-RAY DIFFRACTION 2.38Å
e5oqjU1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e5oqmU1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e6mzmW1[W:330-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e6gykU2[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit,Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e6gylU2[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit,Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e6gymU2[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit,Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e6o9lN2[N:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7lbmM1[M:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7edxQ1[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7eg7Q2[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7eg8Q2[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7eg9Q1[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7egaQ2[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7egbQ2[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvrU2[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvsU1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvtU2[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvuU1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvyU2[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nvzU1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7nw0U1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7egcQ2[Q:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7egdQ2[Q:331-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7enaDQ2[DQ:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TFIIA-a ; ELECTRON MICROSCOPY
e7o4iU1[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit,Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7egiQ1[Q:331-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7egjQ1[Q:331-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7encDQ1[DQ:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TFIIA-a ; ELECTRON MICROSCOPY
e7o4jU1[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7o72U2[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7o73U1[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7o75U1[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7ohaL1[L:227-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7oh9L1[L:228-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7ml2U1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7ml1U1[U:243-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7ml4U1[U:241-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e8ceoU2[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
TOA1 isoform 1 ; ELECTRON MICROSCOPY
e8gxqDQ2[DQ:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e8gxsDQ2[DQ:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7zs9U2[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7zsaU2[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7zsbU2[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
e7zwcU2[U:332-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7zwdU1[U:332-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7zx7U1[U:332-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7zx8U1[U:332-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e7zxeU2[U:332-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e8bvwU1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e8byqU1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e8bz1U1[U:322-376] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA subunit 1 ; ELECTRON MICROSCOPY
e8cenU1[U:229-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transcription initiation factor IIA large subunit ; ELECTRON MICROSCOPY
Domain assembly:
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