Home Help

X - Possible homology level

H - Homology level

T - Topology level

F - Family level

* - Provisional representative

Keyword search

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

X: Repetitive alpha hairpins
H: ARM repeat
T: ARM repeat
F: RPN7

PF10602 CL0020

Representatives:

e4d10A1[A:77-403] nonrep Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 SIGNALOSOME COMPLEX SUBUNIT 1 ; X-RAY DIFFRACTION 3.80Å

e4w9rB2[B:251-379] Image Pymol Jmol Links: PDB, SCOP, CATH

Uncharacterized protein ; ligands: ACT,GOL ; X-RAY DIFFRACTION 2.700Å

e8h3aA1[A:74-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e4w9rA1[A:251-379] Image Pymol Jmol Links: PDB, SCOP, CATH

Uncharacterized protein ; ligands: ACT,GOL ; X-RAY DIFFRACTION 2.700Å

e8h3fA1[A:74-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e5gjqR1[R:14-290] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e4lctD1[D:32-324] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ligands: SO4 ; X-RAY DIFFRACTION 2.7Å

e4b4tR3[R:42-319] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4c0vR2[R:42-319] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4cr2R2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S PROTEASOME REGULATORY SUBUNIT RPN7 ; ELECTRON MICROSCOPY

e4cr3R2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S PROTEASOME REGULATORY SUBUNIT RPN7 ; ELECTRON MICROSCOPY

e4cr4R2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S PROTEASOME REGULATORY SUBUNIT RPN7 ; ELECTRON MICROSCOPY

e4d10I3[I:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 SIGNALOSOME COMPLEX SUBUNIT 1 ; X-RAY DIFFRACTION 3.80Å

e4d18A3[A:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 SIGNALOSOME COMPLEX SUBUNIT 1 ; X-RAY DIFFRACTION 4.08Å

e4d18I3[I:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 SIGNALOSOME COMPLEX SUBUNIT 1 ; X-RAY DIFFRACTION 4.08Å

e4lctA2[A:32-324] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ligands: SO4 ; X-RAY DIFFRACTION 2.7Å

e4lctB2[B:32-324] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ligands: SO4 ; X-RAY DIFFRACTION 2.7Å

e5a5bR2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S PROTEASOME REGULATORY SUBUNIT RPN7 ; ELECTRON MICROSCOPY

e4wsnA1[A:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e4wsnI1[I:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e4wsnQ2[Q:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e4wsnY2[Y:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e4wsng1[g:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e4wsno3[o:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; X-RAY DIFFRACTION 5.500Å

e3jckD2[D:21-72,D:93-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e4lctC1[C:32-324] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ligands: SO4 ; X-RAY DIFFRACTION 2.7Å

e3jcoR1[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e3jcpR2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5l4kR1[R:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5gjrR2[R:14-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5gjr53[5:14-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0gY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0hY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0iY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0jY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0cAY2[AY:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5t0cBY3[BY:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5mpdR2[R:20-70,R:95-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5mpeR2[R:20-70,R:95-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5mpbR2[R:20-70,R:95-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5mpcR3[R:20-70,R:95-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5wviR2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5wvkR3[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5ln3R1[R:16-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5m32m1[m:14-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vgzY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vhfY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vhhY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vhiY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vhsY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6epcR1[R:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome (Prosome, macropain) 26S subunit, non-ATPase, 6 ; ELECTRON MICROSCOPY

e6epdR2[R:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome (Prosome, macropain) 26S subunit, non-ATPase, 6 ; ELECTRON MICROSCOPY

e6epeR2[R:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome (Prosome, macropain) 26S subunit, non-ATPase, 6 ; ELECTRON MICROSCOPY

e6epfR1[R:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome (Prosome, macropain) 26S subunit, non-ATPase, 6 ; ELECTRON MICROSCOPY

e6fvtR2[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6fvwR1[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e5vfpY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vfqY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vfrY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vfsY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vftY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e5vfuY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6fvuR1[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6fvvR3[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6fvxR2[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6fvyR1[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6mseY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6msgY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6mshY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6msjY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6mskY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6msbY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6msdY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6j2cR2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6j2qR2[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6j2xR1[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6j2nR3[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6j30R1[R:23-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e6r6hA1[A:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e6r7fA3[A:37-357] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e6r7hA1[A:37-357] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e6r7iA1[A:70-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e6r7nA2[A:77-393] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

e6wjdY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e6wjnY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qo5R2[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e7w37Y3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w38Y3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w39Y2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3aY1[Y:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3bY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3cY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3fY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3gY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3hY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3iY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3jY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3kY1[Y:1-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7w3mY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e8amzR2[R:7-279] Image Pymol Jmol Links: PDB, SCOP, CATH

PCI domain-containing protein ; ELECTRON MICROSCOPY

e7qo3R2[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e7qo6R1[R:20-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome regulatory subunit RPN7 ; ELECTRON MICROSCOPY

e8cvtY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qxnY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qxpY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qxuY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qxwY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qxxY2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qy7Y2[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qyaY1[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e7qybY3[Y:12-282] Image Pymol Jmol Links: PDB, SCOP, CATH

26S proteasome non-ATPase regulatory subunit 6 ; ELECTRON MICROSCOPY

e8h38A2[A:74-398] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

COP9 signalosome complex subunit 1 ; ELECTRON MICROSCOPY

F: Unmapped domains

Pseudo group of domains that do not map to PFam family profiles. Domains inside should not be considered as in one family.

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

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