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/m.gif)
Refs: Structure 14, 1489-1498; Current opinion in structural biology 18, 358-365
![](/ecod/img/m.gif)
![](/ecod/img/m.gif)
152436, 2-crossover-3, 5-crossover-6
![](/ecod/img/m.gif)
Representatives:
e1twfB1[B:814-850,B:975-1097]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II 140 KDA POLYPEPTIDE ; ligands: MN,UTP ; X-RAY DIFFRACTION 2.3Å
e1smyC8[C:663-700,C:834-999]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE BETA CHAIN ; ligands: G4P,MG ; X-RAY DIFFRACTION 2.7Å
e4c2mB5[B:762-798,B:912-1040]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE I SUBUNIT RPA135 ; X-RAY DIFFRACTION 2.80Å
e5m3fB3[B:762-798,B:912-1040] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase I subunit RPA135 ; ELECTRON MICROSCOPY
e5m3mB7[B:762-798,B:912-1040] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase I subunit RPA135 ; ELECTRON MICROSCOPY
e7okxB2[B:845-882,B:1007-1132] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ok0B2[B:710-747,B:871-996] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit B ; ELECTRON MICROSCOPY
e6rflB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-dependent RNA polymerase subunit rpo132 ; ELECTRON MICROSCOPY
e6ricB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-dependent RNA polymerase subunit rpo132 ; ELECTRON MICROSCOPY
e6ridB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-dependent RNA polymerase subunit rpo132 ; ELECTRON MICROSCOPY
e6rieB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-dependent RNA polymerase subunit rpo132 ; ELECTRON MICROSCOPY
e7okyB2[B:845-882,B:1007-1132] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ol0B2[B:845-882,B:1007-1132] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oq4B2[B:710-747,B:871-996] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit B ; ELECTRON MICROSCOPY
e7oqyB2[B:710-747,B:871-996] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit B ; ELECTRON MICROSCOPY
e7amvB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7aofB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7aohB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7aozB2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7ap8B2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7ap9B2[B:733-769,B:878-1022] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase ; ELECTRON MICROSCOPY
e7eu0B2[B:762-799,B:909-1044] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerases IV and V subunit 2 ; ELECTRON MICROSCOPY
e7eu1B2[B:762-799,B:909-1044] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerases IV and V subunit 2 ; ELECTRON MICROSCOPY
e7fjiB2[B:729-766,B:892-1016] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase III subunit RPC2 ; ELECTRON MICROSCOPY
e7fjjB2[B:729-766,B:892-1016] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase III subunit RPC2 ; ELECTRON MICROSCOPY
e7oo3B2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oobB2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oopB2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7opcB2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7opdB2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oznB2[B:769-805,B:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oznN2[N:769-805,N:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozoB2[B:769-805,B:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozoN2[N:769-805,N:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozpB2[B:769-805,B:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozpN2[N:769-805,N:930-1061] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7pksB2[B:768-805,B:930-1055] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e4by7B5[B:814-850,B:975-1097]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB2 ; X-RAY DIFFRACTION 3.15Å
e2e2iB8[B:814-850,B:975-1097]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II 140 KDA POLYPEPTIDE ; ligands: DGT ; X-RAY DIFFRACTION 3.41Å
![](/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