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:
e1a4iA1[A:127-296]
nonrep
Image
Pymol
Jmol Links:
PDB,
SCOP,
CATH, PubMed,
DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE / METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE ; ligands: NDP ; X-RAY DIFFRACTION 1.5Å
e1diaA1[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE/CYCLOHYDROLASE ; ligands: L24,NAP ; X-RAY DIFFRACTION 2.2Å
e1dibB1[B:1127-1296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE/CYCLOHYDROLASE ; ligands: NAP ; X-RAY DIFFRACTION 2.7Å
e1diaB1[B:1127-1296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE/CYCLOHYDROLASE ; ligands: NAP ; X-RAY DIFFRACTION 2.2Å
e1a4iB1[B:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE / METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE ; ligands: NDP ; X-RAY DIFFRACTION 1.5Å
e1digA1[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE / CYCLOHYDROLASE ; ligands: L37,NAP ; X-RAY DIFFRACTION 2.2Å
e1digB1[B:1127-1296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE / CYCLOHYDROLASE ; ligands: ACT,NAP ; X-RAY DIFFRACTION 2.2Å
e1dibA1[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE/CYCLOHYDROLASE ; ligands: L34,NAP ; X-RAY DIFFRACTION 2.7Å
e1b0aA1[A:123-284] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed,
PROTEIN (FOLD BIFUNCTIONAL PROTEIN) ; X-RAY DIFFRACTION 2.56Å
e4a26A1[A:125-298] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PUTATIVE C-1-TETRAHYDROFOLATE SYNTHASE, CYTOPLASMIC ; ligands: CL ; X-RAY DIFFRACTION 2.7Å
e3l07A1[A:121-281] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein folD ; ligands: EDO,IMD,PO4 ; X-RAY DIFFRACTION 1.880Å
e3p2oA1[A:120-281] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein folD ; ligands: GOL,NAD ; X-RAY DIFFRACTION 2.23Å
e3nglA1[A:115-276] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein folD ; ligands: NAP ; X-RAY DIFFRACTION 2.4Å
e4a5oA1[A:123-284] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: GOL,PEG ; X-RAY DIFFRACTION 2.2Å
e2c2xA1[A:122-281] Image Pymol Jmol Links: PDB, SCOP, CATH
METHYLENETETRAHYDROFOLATE DEHYDROGENASE-METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE ; X-RAY DIFFRACTION 2.010Å
e2c2xB1[B:122-281] Image Pymol Jmol Links: PDB, SCOP, CATH
METHYLENETETRAHYDROFOLATE DEHYDROGENASE-METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE ; X-RAY DIFFRACTION 2.010Å
e2c2yA1[A:122-281] Image Pymol Jmol Links: PDB, SCOP, CATH
METHYLENETETRAHYDROFOLATE DEHYDROGENASE-METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE ; X-RAY DIFFRACTION 2.020Å
e3l07B1[B:121-282] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein folD ; ligands: ACT,EDO,IMD ; X-RAY DIFFRACTION 1.880Å
e3p2oB1[B:120-281] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein folD ; ligands: GOL,NAD ; X-RAY DIFFRACTION 2.23Å
e4a26B1[B:125-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
PUTATIVE C-1-TETRAHYDROFOLATE SYNTHASE, CYTOPLASMIC ; ligands: CL ; X-RAY DIFFRACTION 2.7Å
e4a5oD1[D:123-283] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; X-RAY DIFFRACTION 2.2Å
e3nglC1[C:115-275] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein folD ; ligands: NAP ; X-RAY DIFFRACTION 2.4Å
e3ngxA1[A:115-276] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein folD ; X-RAY DIFFRACTION 2.20Å
e3ngxB1[B:115-276] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein folD ; X-RAY DIFFRACTION 2.20Å
e4a5oB1[B:123-284] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; X-RAY DIFFRACTION 2.2Å
e4a5oC1[C:123-284] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; X-RAY DIFFRACTION 2.2Å
e4b4uA1[A:121-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: CL,EDO,NAP,PEG ; X-RAY DIFFRACTION 1.45Å
e1ee9A1[A:149-319] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
5,10-METHYLENETETRAHYDROFOLATE DEHYDROGENASE ; ligands: NAD ; X-RAY DIFFRACTION 2.9Å
e4b4wB3[B:122-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: 9L9,NAP ; X-RAY DIFFRACTION 2.00Å
e4b4vB3[B:122-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: L34,NAP ; X-RAY DIFFRACTION 2.00Å
e4b4vA3[A:122-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: GOL,L34,NAP ; X-RAY DIFFRACTION 2.00Å
e4b4wA3[A:122-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: 9L9,GOL,NAP ; X-RAY DIFFRACTION 2.00Å
e4cjxA2[A:125-297] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
C-1-TETRAHYDROFOLATE SYNTHASE, CYTOPLASMIC, PUTATIVE ; ligands: 9L9,GOL,NAP,PEG ; X-RAY DIFFRACTION 2.05Å
e4cjxB2[B:125-297] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
C-1-TETRAHYDROFOLATE SYNTHASE, CYTOPLASMIC, PUTATIVE ; ligands: 9L9,PEG ; X-RAY DIFFRACTION 2.05Å
e4b4uB1[B:122-282] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
BIFUNCTIONAL PROTEIN FOLD ; ligands: CL,EDO,NAP ; X-RAY DIFFRACTION 1.45Å
e5tc4A1[A:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: L34,NAD,PO4 ; X-RAY DIFFRACTION 1.89Å
e6apeA1[A:126-288] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: GOL,NA ; X-RAY DIFFRACTION 1.450Å
e5nhsA2[A:132-296] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: EDO ; X-RAY DIFFRACTION 2.11Å
e5nhsB1[B:132-295] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; X-RAY DIFFRACTION 2.11Å
e6debA1[A:120-282] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: CL,DTT,GOL,GUN,TRS ; X-RAY DIFFRACTION 1.7Å
e6de8A1[A:120-281] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: GOL,IOD ; X-RAY DIFFRACTION 2.1Å
e5o22A1[A:123-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; ligands: C3R ; X-RAY DIFFRACTION 2.1Å
e5o22B1[B:123-284] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; ligands: C3R ; X-RAY DIFFRACTION 2.1Å
e5o22C1[C:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; ligands: C3R ; X-RAY DIFFRACTION 2.1Å
e5o22D2[D:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; ligands: C3R ; X-RAY DIFFRACTION 2.1Å
e5o28A2[A:123-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.890Å
e5o28B1[B:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.890Å
e5o28C1[C:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.890Å
e5o28D1[D:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.890Å
e5o2aA1[A:123-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.9Å
e5o2aB2[B:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.9Å
e5o2aC1[C:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.9Å
e5o2aD2[D:123-285] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; X-RAY DIFFRACTION 1.9Å
e6de8B2[B:120-281] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: GOL,IOD,K ; X-RAY DIFFRACTION 2.1Å
e6debB2[B:120-282] Image Pymol Jmol Links: PDB, SCOP, CATH
Bifunctional protein FolD ; ligands: CL,DTT,GOL,MTX,TRS ; X-RAY DIFFRACTION 1.7Å
e5zf1A2[A:122-299] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
5,10-methylenetetrahydrofolate dehydrogenase ; ligands: EDO,SO4 ; X-RAY DIFFRACTION 1.75Å
e5zf1B1[B:122-299] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
5,10-methylenetetrahydrofolate dehydrogenase ; ligands: EDO,SO4 ; X-RAY DIFFRACTION 1.75Å
e6ecpA2[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Methylenetetrahydrofolate dehydrogenase cyclohydrolase ; ligands: 21V,NAP ; X-RAY DIFFRACTION 2.200Å
e6ecpB1[B:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Methylenetetrahydrofolate dehydrogenase cyclohydrolase ; ligands: NAP ; X-RAY DIFFRACTION 2.200Å
e6ecqA2[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE CYCLOHYDROLASE ; ligands: LUD,NAP ; X-RAY DIFFRACTION 2.7Å
e6ecqB1[B:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
METHYLENETETRAHYDROFOLATE DEHYDROGENASE CYCLOHYDROLASE ; ligands: NAP ; X-RAY DIFFRACTION 2.7Å
e6ecrA1[A:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
methylenetetrahydrofolate dehydrogenase cyclohydrolase ; ligands: NAP ; X-RAY DIFFRACTION 2.2Å
e6ecrB2[B:127-296] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
methylenetetrahydrofolate dehydrogenase cyclohydrolase ; ligands: ACT,NAP ; X-RAY DIFFRACTION 2.2Å
e6jibA2[A:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: BQF,GOL,PO4 ; X-RAY DIFFRACTION 2.250Å
e6jibB1[B:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: BQF,GOL,PO4 ; X-RAY DIFFRACTION 2.250Å
e6jidA2[A:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: BQC,GOL,PO4 ; X-RAY DIFFRACTION 2.500Å
e6jidB1[B:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: BQC,GOL,PO4 ; X-RAY DIFFRACTION 2.500Å
e6kg2A1[A:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: D8C,NAD,PO4 ; X-RAY DIFFRACTION 2.250Å
e6kg2B1[B:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: D8C,NAD,PO4 ; X-RAY DIFFRACTION 2.250Å
e6v6yA2[A:119-277] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional protein FolD ; ligands: NAP ; X-RAY DIFFRACTION 2.152Å
e6s4aA1[A:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: KUK,MPD,NAD,PO4 ; X-RAY DIFFRACTION 1.95Å
e6s4aB1[B:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: KUK,MPD,NAD,PO4 ; X-RAY DIFFRACTION 1.95Å
e6s4eA2[A:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: 9L9,NAD,PO4 ; X-RAY DIFFRACTION 1.90Å
e6s4fA1[A:157-332] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: ADP,GOL,KUN,PO4 ; X-RAY DIFFRACTION 2.20Å
e6s4fB1[B:157-333] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial ; ligands: GOL,KUN,PO4 ; X-RAY DIFFRACTION 2.20Å
e7qeiA2[A:171-347] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Probable bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2 ; ligands: 9L9,ATR ; X-RAY DIFFRACTION 2.10Å

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