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:
e2rjzA1[A:67-201]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
PilO protein ; ligands: SO4 ; X-RAY DIFFRACTION 2.20Å
e2rjzB1[B:67-201] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO protein ; ligands: SO4 ; X-RAY DIFFRACTION 2.20Å
e3jc8Ob1[Ob:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oc1[Oc:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Od1[Od:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oe1[Oe:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Of1[Of:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Og1[Og:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oh1[Oh:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oi1[Oi:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oj1[Oj:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Ok1[Ok:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Ol1[Ol:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oa1[Oa:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Ob1[Ob:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oc1[Oc:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Od1[Od:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oe1[Oe:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Of1[Of:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Og1[Og:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oh1[Oh:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oi1[Oi:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Oj1[Oj:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Ok1[Ok:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc9Ol1[Ol:50-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e3jc8Oa1[Oa:49-189] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO ; ELECTRON MICROSCOPY
e5uvrA1[A:109-206] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PilO protein ; X-RAY DIFFRACTION 1.7Å
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