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




Representatives:
e4kc5A3[A:3497-3645]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
RhiE protein ; X-RAY DIFFRACTION 2.14Å
e4kc5B3[B:3497-3645] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RhiE protein ; X-RAY DIFFRACTION 2.14Å
e4kc5C4[C:3497-3645] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RhiE protein ; X-RAY DIFFRACTION 2.14Å
e4kc5D3[D:3497-3645] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
RhiE protein ; X-RAY DIFFRACTION 2.14Å
e4opeA3[A:4658-4802] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS ; X-RAY DIFFRACTION 2.590Å
e4opeC3[C:4658-4802] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS ; ligands: NO3 ; X-RAY DIFFRACTION 2.590Å
e4opeD2[D:4658-4802] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS ; X-RAY DIFFRACTION 2.590Å
e4opeB2[B:4658-4801] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS ; X-RAY DIFFRACTION 2.590Å
e4na1B3[B:447-615] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; ligands: SO4 ; X-RAY DIFFRACTION 1.95Å
e4tktA4[A:3589-3754] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
AT-less polyketide synthase ; ligands: GOL,MES,SO4 ; X-RAY DIFFRACTION 2.4289Å
e4tl2A3[A:994-1069,A:1099-1180] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB
; ligands: CL,EPE
e4na2B3[B:447-614] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; X-RAY DIFFRACTION 2.3Å
e4na1A2[A:457-614] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; ligands: SO4 ; X-RAY DIFFRACTION 1.95Å
e4na2A4[A:457-615] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; X-RAY DIFFRACTION 2.3Å
e4na3A1[A:457-614] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; ligands: SO4 ; X-RAY DIFFRACTION 2.89Å
e4na3B1[B:457-615] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
POLYKETIDE SYNTHASE PKSJ ; ligands: SO4 ; X-RAY DIFFRACTION 2.89Å
e4zdnA3[A:984-1069,A:1099-1180] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
AT-less polyketide synthase ; ligands: CL,EPE ; X-RAY DIFFRACTION 2.509Å
e5e5nA3[A:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 2.00Å
e5e5nB3[B:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 2.00Å
e5e5nC1[C:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 2.00Å
e5e5nD1[D:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 2.00Å
e5e6kA2[A:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; ligands: SO4 ; X-RAY DIFFRACTION 2.16Å
e5e6kB2[B:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 2.16Å
e5erbA1[A:447-615] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase ; X-RAY DIFFRACTION 4.20Å
e5erbB2[B:447-616] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase ; X-RAY DIFFRACTION 4.20Å
e5erbC1[C:447-616] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase ; X-RAY DIFFRACTION 4.20Å
e5erbD1[D:447-616] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase ; X-RAY DIFFRACTION 4.20Å
e5enyA3[A:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyC1[C:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyE2[E:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyG1[G:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5erfA1[A:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 3.1Å
e5erfB1[B:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 3.1Å
e5enyB2[B:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyD1[D:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyF1[F:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5enyH2[H:437-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Polyketide synthase PksL ; X-RAY DIFFRACTION 4.00Å
e5elpD1[D:437-528,D:554-600] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS protein ; X-RAY DIFFRACTION 2.93Å
e5elpA3[A:445-528,A:554-599] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS protein ; X-RAY DIFFRACTION 2.93Å
e5elpC3[C:437-600] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS protein ; X-RAY DIFFRACTION 2.93Å
e5elpB3[B:437-600] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
NRPS/PKS protein ; X-RAY DIFFRACTION 2.93Å
e4z37A2[A:2761-2933] Image Pymol Jmol Links: PDB, SCOP, CATH
Putative mixed polyketide synthase/non-ribosomal peptide synthetase ; X-RAY DIFFRACTION 1.998Å
e4qyrA2[A:2970-3123] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
AT-less polyketide synthase ; ligands: CL ; X-RAY DIFFRACTION 2.9Å
e6mhkA1[A:438-588] Image Pymol Jmol Links: PDB, SCOP, CATH
Polyketide synthase ; X-RAY DIFFRACTION 1.93Å
e6mhlA3[A:431-590] Image Pymol Jmol Links: PDB, SCOP, CATH
Hybrid NRPS/PKS ; X-RAY DIFFRACTION 1.82Å
e6mhkB3[B:438-588] Image Pymol Jmol Links: PDB, SCOP, CATH
Polyketide synthase ; X-RAY DIFFRACTION 1.93Å
e6mhlB3[B:431-590] Image Pymol Jmol Links: PDB, SCOP, CATH
Hybrid NRPS/PKS ; X-RAY DIFFRACTION 1.82Å
e7s2xA1[A:434-597] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
SalC ; X-RAY DIFFRACTION 2.85Å
e7s2xB2[B:435-597] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
SalC ; ligands: K ; X-RAY DIFFRACTION 2.85Å
e7s2xC1[C:435-597] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
SalC ; X-RAY DIFFRACTION 2.85Å
e7s2xD3[D:435-597] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
SalC ; ligands: EPE ; X-RAY DIFFRACTION 2.85Å
e7zmaA3[A:2031-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zmaB2[B:2030-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskB7[B:961-1129] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskA7[A:961-1129] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskD7[D:961-1129] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskC7[C:961-1129] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zmdA2[A:959-1130] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zmdB3[B:959-1130] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskB5[B:2031-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskA5[A:2031-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskD5[D:2031-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zskC5[C:2031-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ELECTRON MICROSCOPY
e7zmcB2[B:2031-2200] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; X-RAY DIFFRACTION 3.10Å
e7zmcA1[A:2030-2199] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; X-RAY DIFFRACTION 3.10Å
e7zm9A3[A:959-1130] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Putative polyketide synthase ; ligands: GOL,PEG ; X-RAY DIFFRACTION 1.62Å
e6iyoB1[B:1-80] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Type I modular polyketide synthase ; X-RAY DIFFRACTION 2.200Å
e8g4uA5[A:1916-2015] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
EryAIII ; X-RAY DIFFRACTION 2.9Å
e8g4uD2[D:1916-2015] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
EryAIII ; X-RAY DIFFRACTION 2.9Å
e8g4uC5[C:1915-2006] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
EryAIII ; X-RAY DIFFRACTION 2.9Å
e8g4uB2[B:1918-2013] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
EryAIII ; X-RAY DIFFRACTION 2.9Å
e5bp1A3[A:440-537] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Mycocerosic acid synthase ; X-RAY DIFFRACTION 2.203Å

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