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
![](/ecod/img/m.gif)
![](/ecod/img/p.gif)
![](/ecod/img/p.gif)
![](/ecod/img/m.gif)
Representatives:
e1twfB4[B:18-218,B:405-541]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II 140 KDA POLYPEPTIDE ; X-RAY DIFFRACTION 2.3Å
e2nvqB2[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II 140 kDa polypeptide ; X-RAY DIFFRACTION 2.90Å
e2nvtB3[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II 140 KDA POLYPEPTIDE ; X-RAY DIFFRACTION 3.36Å
e3rzdB7[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.300Å
e3rzoB4[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.000Å
e3s14B1[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 2.850Å
e3s15B1[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.300Å
e3s16B7[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB2 ; X-RAY DIFFRACTION 3.24Å
e3s17B2[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.200Å
e3s1mB6[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.130Å
e3s1nB2[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.100Å
e3s1qB5[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.300Å
e3s1rB5[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; ligands: GTP ; X-RAY DIFFRACTION 3.200Å
e3s2dB7[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.200Å
e3s2hB4[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II subunit RPB2 ; X-RAY DIFFRACTION 3.300Å
e2yu9B7[B:20-138,B:164-218,B:405-541] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase II 140 kDa polypeptide ; X-RAY DIFFRACTION 3.400Å
e7okxB1[B:92-276,B:468-605] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7okyB1[B:92-276,B:468-605] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ol0B1[B:92-276,B:468-605] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oo3B1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oobB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oopB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7opcB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7opdB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oznB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7oznN1[N:15-199,N:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozoB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozoN1[N:15-199,N:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozpB1[B:15-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7ozpN1[N:15-199,N:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e7pksB1[B:14-199,B:391-528] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
DNA-directed RNA polymerase subunit beta ; ELECTRON MICROSCOPY
e1smyC4[C:1-142,C:332-457]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE BETA CHAIN ; ligands: MG ; X-RAY DIFFRACTION 2.7Å
e4c2mB1[B:8-209,B:401-547]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE I SUBUNIT RPA135 ; ligands: SO4 ; X-RAY DIFFRACTION 2.80Å
e4by7B1[B:20-134,B:164-218,B:405-541]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II SUBUNIT RPB2 ; X-RAY DIFFRACTION 3.15Å
e2e2iB10[B:20-218,B:405-541]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
DNA-DIRECTED RNA POLYMERASE II 140 KDA POLYPEPTIDE ; X-RAY DIFFRACTION 3.41Å
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