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
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




Representatives:
e1pq4A1[A:47-139,A:174-218]
nonrep
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periplasmic binding protein component of an ABC type zinc uptake transporter ; ligands: ZN ; X-RAY DIFFRACTION 1.8Å
e1pq4A2[A:219-335]
nonrep
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periplasmic binding protein component of an ABC type zinc uptake transporter ; ligands: ZN ; X-RAY DIFFRACTION 1.8Å
e1toaA1[A:32-174]
nonrep
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PROTEIN (PERIPLASMIC BINDING PROTEIN TROA) ; ligands: GOL,ZN ; X-RAY DIFFRACTION 1.8Å
e1toaA2[A:175-308]
nonrep
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PROTEIN (PERIPLASMIC BINDING PROTEIN TROA) ; ligands: ZN ; X-RAY DIFFRACTION 1.8Å
e1pszA1[A:24-178]
nonrep
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PROTEIN (SURFACE ANTIGEN PSAA) ; ligands: ZN ; X-RAY DIFFRACTION 2.0Å
e3hh8A1[A:30-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Metal ABC transporter substrate-binding lipoprotein ; ligands: FE ; X-RAY DIFFRACTION 1.86Å
e4k3vA1[A:14-162] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ABC SUPERFAMILY ATP BINDING CASSETTE TRANSPORTER, BINDING PROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.2Å
e4k3vB2[B:14-162] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ABC SUPERFAMILY ATP BINDING CASSETTE TRANSPORTER, BINDING PROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.2Å
e4nnoA2[A:32-179] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Lipoprotein ; ligands: ZN ; X-RAY DIFFRACTION 1.17Å
e4nnpA1[A:32-179] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Lipoprotein ; X-RAY DIFFRACTION 2.69Å
e4nnpB2[B:32-179] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Lipoprotein ; X-RAY DIFFRACTION 2.69Å
e4oxqA1[A:29-176] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Manganese ABC transporter, periplasmic-binding protein SitA ; ligands: ZN ; X-RAY DIFFRACTION 2.62Å
e4oxqB1[B:29-176] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Manganese ABC transporter, periplasmic-binding protein SitA ; X-RAY DIFFRACTION 2.62Å
e4oxrA2[A:29-176] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Manganese ABC transporter, periplasmic-binding protein SitA ; ligands: MN ; X-RAY DIFFRACTION 2.0Å
e4oxrB1[B:29-176] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Manganese ABC transporter, periplasmic-binding protein SitA ; ligands: MN ; X-RAY DIFFRACTION 2.0Å
e4utoA2[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: CD,TRS ; X-RAY DIFFRACTION 1.55Å
e4utoB2[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: CD,TRS ; X-RAY DIFFRACTION 1.55Å
e4utpA2[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: CD ; X-RAY DIFFRACTION 2.00Å
e4utpB1[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: CD ; X-RAY DIFFRACTION 2.00Å
e4xrvA1[A:26-115,A:135-177] Image Pymol Jmol Links: PDB, SCOP, CATH
; ligands: ZN
e4xrvB1[B:27-177] Image Pymol Jmol Links: PDB, SCOP, CATH
; ligands: ZN
e3zk7A1[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.69Å
e3zk7B1[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.69Å
e3zk8A2[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.65Å
e3zk8B1[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.65Å
e3zk9A1[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.45Å
e3zk9B1[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: TRS ; X-RAY DIFFRACTION 1.45Å
e3zkaA2[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN,TRS ; X-RAY DIFFRACTION 1.55Å
e3zkaB2[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN,TRS ; X-RAY DIFFRACTION 1.55Å
e3zttA1[A:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.74Å
e3zttB1[B:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.74Å
e3zttC2[C:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.74Å
e3zttD1[D:32-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
MANGANESE ABC TRANSPORTER SUBSTRATE-BINDING LIPOPROTEIN ; ligands: MN ; X-RAY DIFFRACTION 2.74Å
e5hx7A1[A:32-179] Image Pymol Jmol Links: PDB, SCOP, CATH
Manganese-binding lipoprotein MntA ; X-RAY DIFFRACTION 1.750Å
e5i4kA2[A:31-179] Image Pymol Jmol Links: PDB, SCOP, CATH
Manganese-binding lipoprotein MntA ; ligands: CL,MN ; X-RAY DIFFRACTION 1.79Å
e5jpdA1[A:31-179] Image Pymol Jmol Links: PDB, SCOP, CATH
Manganese-binding lipoprotein MntA ; ligands: CD,CL ; X-RAY DIFFRACTION 1.720Å
e5hdqA2[A:16-162] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
ABC transporter substrate-binding protein ; ligands: FE ; X-RAY DIFFRACTION 1.83Å
e1pszA2[A:179-309]
nonrep
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Pymol
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PROTEIN (SURFACE ANTIGEN PSAA) ; ligands: ZN ; X-RAY DIFFRACTION 2.0Å

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