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
![](/ecod/img/m.gif)
![](/ecod/img/p.gif)
![](/ecod/img/p.gif)
![](/ecod/img/m.gif)
Representatives:
e1twfA2[A:1113-1141,A:1273-1330]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II LARGEST SUBUNIT ; X-RAY DIFFRACTION 2.3Å
e7f4gA8[A:1136-1162,A:1300-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e8b3fA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH
; ELECTRON MICROSCOPY
e8oevA1[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8oewA1[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8of0A3[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8p4bA9[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8p4cA3[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8p4dA4[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8p4eA6[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e5ip7A6[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.520Å
e5ip9A4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.450Å
e5fywA1[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB1 ; ELECTRON MICROSCOPY
e5fz5A6[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB1 ; ELECTRON MICROSCOPY
e5iy6A7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iy7A5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iy8A4[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iy9A7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iyaA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iybA4[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iycA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5iydA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e3h0gM4[M:1116-1144,M:1279-1336] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit rpb1 ; X-RAY DIFFRACTION 3.650Å
e1i50A4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II LARGEST SUBUNIT ; X-RAY DIFFRACTION 2.8Å
e2nvyA4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II LARGEST SUBUNIT ; X-RAY DIFFRACTION 3.4Å
e4bxxA6[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB1 ; X-RAY DIFFRACTION 3.28Å
e3cqzA4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB1 ; X-RAY DIFFRACTION 2.8Å
e5flmA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE ; ELECTRON MICROSCOPY
e5oikA7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5oqjA9[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e5oqmA7[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e6blpA7[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.2Å
e6bm2A3[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.4Å
e6bm4A3[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 2.95Å
e6bqfA3[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.35Å
e6exvA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB1 ; ELECTRON MICROSCOPY
e6gmlA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e6gykA4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e6gylA4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e6gymA4[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7b0yA6[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7lbmA6[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7edxo3[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7eg7o9[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7eg8o1[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7eg9o4[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7egao2[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7egbo8[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7nvrA2[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7nvsA7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7nvtA7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7nvuA7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7nvyA6[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7nvzA2[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7nw0A5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e6xreA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7egco4[o:1136-1164,o:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7okxA9[A:1136-1164,A:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7nkxA9[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e6gmhA8[A:1135-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7okyA9[A:1136-1164,A:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7ol0A8[A:1135-1163,A:1300-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7oznA8[A:1136-1164,A:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7oznM8[M:1136-1164,M:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RPB1 ; ELECTRON MICROSCOPY
e7ozoA8[A:1136-1164,A:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ozoM8[M:1136-1164,M:1299-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ozpA8[A:1136-1164,A:1297-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ozpM8[M:1136-1164,M:1297-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7pksA9[A:1136-1163,A:1300-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7oobA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7ml0A9[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ml1A8[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ml2A2[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ml4A2[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ripA3[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.270Å
e7riqA9[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 2.960Å
e7riwA2[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.17Å
e7rixA6[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.3Å
e7riyA3[A:1113-1141,A:1273-1330] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; X-RAY DIFFRACTION 3.630Å
e7oo3A5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7oopA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7opcA3[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7opdA7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1 ; ELECTRON MICROSCOPY
e7zwdA2[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7zx7A6[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7zx8A7[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e8bvwA2[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e8byqA8[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e8bz1A9[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit ; ELECTRON MICROSCOPY
e7ycx14[1:1136-1164,1:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB1,DNA-directed RNA polymerase II subunit RPB1, CTD1, CTD2, CTD3, CTD4 ; ELECTRON MICROSCOPY
e8p4fA5[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8a40A2[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8b3dA4[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH
; ELECTRON MICROSCOPY
e8oeuA3[A:1136-1164,A:1298-1360] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
; ELECTRON MICROSCOPY
e8p4aA7[A:1136-1164,A:1298-1360] 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.
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