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:
e1rtqA1[A:1-291]
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BACTERIAL LEUCYL AMINOPEPTIDASE ; ligands: NA,SCN,ZN ; X-RAY DIFFRACTION 0.95Å
e6gbxB1[B:34-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,S77,SO4,ZN ; X-RAY DIFFRACTION 1.72Å
e6gbxC1[C:34-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,S77,SO4,ZN ; X-RAY DIFFRACTION 1.72Å
e6d03B2[B:120-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; ELECTRON MICROSCOPY
e6d04A2[A:120-189,A:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; ELECTRON MICROSCOPY
e6d04B2[B:120-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; ELECTRON MICROSCOPY
e6d05A2[A:120-189,A:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; ELECTRON MICROSCOPY
e6d05B3[B:120-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; ELECTRON MICROSCOPY
e6etyA1[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: BXK,CA,CL,NAG,ZN ; X-RAY DIFFRACTION 1.68Å
e6h7yA1[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,EDO,FVZ,NAG,PEG,PGE,TAM,ZN ; X-RAY DIFFRACTION 1.81Å
e6h7zA2[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,EDO,FVW,NAG,PEG,TRS,ZN ; X-RAY DIFFRACTION 2Å
e6hkjA2[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,G8W,NAG,TAM,ZN ; X-RAY DIFFRACTION 2.09Å
e6hkzA3[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,GBZ,NAG,ZN ; X-RAY DIFFRACTION 2.09Å
e6f5lA3[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,CQB,NAG,PGE,ZN ; X-RAY DIFFRACTION 1.63Å
e6ez9A1[A:55-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: C68,CA,CL,NAG,ZN ; X-RAY DIFFRACTION 1.61Å
e6fe5A1[A:55-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,D6E,NAG,ZN ; X-RAY DIFFRACTION 1.52Å
e6qqlA1[A:41-329] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: ZN ; X-RAY DIFFRACTION 2.810Å
e6qroA1[A:43-334] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: SO4,ZN ; X-RAY DIFFRACTION 2.100Å
e6qqlB1[B:41-328] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: ZN ; X-RAY DIFFRACTION 2.810Å
e6qroB1[B:43-334] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: SO4,ZN ; X-RAY DIFFRACTION 2.100Å
e6qroC1[C:44-334] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: SO4,ZN ; X-RAY DIFFRACTION 2.100Å
e6qroD1[D:43-334] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamine cyclotransferase ; ligands: SO4,ZN ; X-RAY DIFFRACTION 2.100Å
e6gsrAb1[Ab:121-189,Ab:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
e6gsrAq3[Aq:121-189,Aq:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
e6h5iAb3[Ab:121-189,Ab:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
e6h5iAq3[Aq:121-189,Aq:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
e6hc6A1[A:39-120,A:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase YwaD ; ligands: ACT,GOL,ZN ; X-RAY DIFFRACTION 1.77Å
e6hc6B1[B:39-120,B:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase YwaD ; ligands: ACT,GOL,ZN ; X-RAY DIFFRACTION 1.77Å
e6hc6C2[C:39-120,C:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase YwaD ; ligands: ACT,GOL,ZN ; X-RAY DIFFRACTION 1.77Å
e6hc7A2[A:39-120,A:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase Y (Arg Lys Leu preference) ; ligands: ACT,CL,SO4,ZN ; X-RAY DIFFRACTION 2.5Å
e6hc7B2[B:39-120,B:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase Y (Arg Lys Leu preference) ; ligands: ACT,CL,SO4,ZN ; X-RAY DIFFRACTION 2.5Å
e6hc7C1[C:39-120,C:222-455] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase Y (Arg Lys Leu preference) ; ligands: ACT,CL,SO4,ZN ; X-RAY DIFFRACTION 2.5Å
e6icaA2[A:142-424] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase ; ligands: ACT,GOL,SO4,ZN ; X-RAY DIFFRACTION 2.195Å
e6icaB2[B:142-424] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase ; ligands: GOL,SO4,ZN ; X-RAY DIFFRACTION 2.195Å
e6icaC1[C:142-424] Image Pymol Jmol Links: PDB, SCOP, CATH
Aminopeptidase ; ligands: GOL,SO4,ZN ; X-RAY DIFFRACTION 2.195Å
e6okdA2[A:2-71,A:265-490] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: GOL ; X-RAY DIFFRACTION 1.850Å
e6okdB1[B:3-71,B:265-490] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: GOL ; X-RAY DIFFRACTION 1.850Å
e6rbcA2[A:55-117,A:351-593] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,JX5,NAG,ZN ; X-RAY DIFFRACTION 1.77Å
e6yi1A1[A:33-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: 66N,DIO,GOL,ORT,PEG,PG4,PHE,SO4,ZN ; X-RAY DIFFRACTION 1.920Å
e6yi1B1[B:33-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: 66N,DIO,GOL,MES,ORT,PEG,PGE,PHE,SO4,ZN ; X-RAY DIFFRACTION 1.920Å
e6yjyA1[A:33-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: GLN,LEU,MES,PCA,SO4,TYR,ZN ; X-RAY DIFFRACTION 1.670Å
e6yjyB1[B:33-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: GLN,LEU,MES,PCA,SO4,TYR,ZN ; X-RAY DIFFRACTION 1.670Å
e6rtiA1[A:56-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,G88,MPD,ZN ; X-RAY DIFFRACTION 2.20Å
e6s1xA1[A:55-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamate carboxypeptidase 2 ; ligands: CA,CL,KRZ,NAG,ZN ; X-RAY DIFFRACTION 1.76Å
e6sgpA1[A:55-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamate carboxypeptidase 2 ; ligands: CA,CL,LDK,NA,NAG,PEG,PGE,ZN ; X-RAY DIFFRACTION 1.58Å
e6skhA3[A:55-117,A:351-591] Image Pymol Jmol Links: PDB, SCOP, CATH
Glutamate carboxypeptidase 2 ; ligands: CA,CL,EDO,GOL,LHK,NAG,ZN ; X-RAY DIFFRACTION 1.58Å
e7cozA1[A:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,Q39,SO4,ZN ; X-RAY DIFFRACTION 1.850Å
e7cozB1[B:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,Q39,SO4,ZN ; X-RAY DIFFRACTION 1.850Å
e7cozC1[C:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,Q39,SO4,ZN ; X-RAY DIFFRACTION 1.850Å
e7cp0A1[A:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,SO4,ZN ; X-RAY DIFFRACTION 1.700Å
e7cp0B1[B:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,SO4,ZN ; X-RAY DIFFRACTION 1.700Å
e7cp0C1[C:35-361] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EDO,SO4,ZN ; X-RAY DIFFRACTION 1.700Å
e7d17A1[A:29-357] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: ZN ; X-RAY DIFFRACTION 2.98Å
e7d1dA1[A:38-331] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamine cyclotransferase ; ligands: 1BN,ZN ; X-RAY DIFFRACTION 1.75Å
e7d18A1[A:16-286] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Peptidase M28 ; ligands: GOL,NA,SO4,TRS,ZN ; X-RAY DIFFRACTION 1.33Å
e7d21A1[A:25-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: EPE,ZN ; X-RAY DIFFRACTION 1.97Å
e6wrwB3[B:121-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA ; X-RAY DIFFRACTION 2.77Å
e7d1bA1[A:27-30,A:67-364] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Leucine aminopeptidase ; ligands: CL,GOL,PG5,ZN ; X-RAY DIFFRACTION 1.24Å
e7d1eA1[A:40-331] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Leucine aminopeptidase ; ligands: AHN,ZN ; X-RAY DIFFRACTION 1.85Å
e6wrvA1[A:121-189,A:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA ; X-RAY DIFFRACTION 2.47Å
e6wrvB1[B:121-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA ; X-RAY DIFFRACTION 2.47Å
e6wrvE3[E:121-189,E:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA ; X-RAY DIFFRACTION 2.47Å
e6wrwA1[A:121-189,A:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA ; X-RAY DIFFRACTION 2.77Å
e6wrxA3[A:121-189,A:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; X-RAY DIFFRACTION 3.067Å
e7d1hA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: ZN ; X-RAY DIFFRACTION 1.69Å
e7d1nA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: BCT,CU ; X-RAY DIFFRACTION 2.26Å
e7d1pA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: BCT,CD ; X-RAY DIFFRACTION 2.36Å
e7d1yA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: CO ; X-RAY DIFFRACTION 1.95Å
e7d23A1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: K,TRS ; X-RAY DIFFRACTION 1.40Å
e7d2bA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: NI ; X-RAY DIFFRACTION 1.99Å
e7d2dA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: MN ; X-RAY DIFFRACTION 1.80Å
e7d2iA1[A:29-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: FE,SO4 ; X-RAY DIFFRACTION 1.85Å
e7d2jA1[A:28-353] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutaminyl-peptide cyclotransferase ; ligands: BCT,CD ; X-RAY DIFFRACTION 1.60Å
e6wrxB1[B:121-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ligands: CA,NAG ; X-RAY DIFFRACTION 3.067Å
e6zepA1[A:26-377] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Leucine aminopeptidase A ; ligands: CL,EDO,ZN ; X-RAY DIFFRACTION 1.61Å
e7cjeC1[C:41-329] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamine cyclotransferase-related protein ; ligands: MG,ZN ; X-RAY DIFFRACTION 1.95Å
e7oezA1[A:77-377] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Leucine aminopeptidase A ; ligands: CL,EDO,LEU,SO4,ZN ; X-RAY DIFFRACTION 2.48Å
e6zeqA1[A:77-377] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Leucine aminopeptidase A ; ligands: CL,EDO,SO4,ZN ; X-RAY DIFFRACTION 1.97Å
e7cjeA1[A:41-328] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamine cyclotransferase-related protein ; ligands: GOL,MG,ZN ; X-RAY DIFFRACTION 1.95Å
e7cjgA1[A:41-329] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamine cyclotransferase-related protein ; ligands: DMD,GOL,MG,NO3,ZN ; X-RAY DIFFRACTION 2.000Å
e7cjgB1[B:41-328] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Glutamine cyclotransferase-related protein ; ligands: DMD,GOL,MG,NO3,ZN ; X-RAY DIFFRACTION 2.000Å
e7zqsB3[B:120-189,B:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
e7zqsD1[D:120-189,D:383-608] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI
Transferrin receptor protein 1 ; ELECTRON MICROSCOPY
Previouse1tkjA1[A:1-277]
nonrep
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AMINOPEPTIDASE ; ligands: CA,MED,ZN ; X-RAY DIFFRACTION 1.15Å
e3bi1A2[A:57-117,A:351-593]
nonrep
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GLUTAMATE CARBOXYPEPTIDASE 2 ; ligands: 3BI,CA,CL,NAG,ZN ; X-RAY DIFFRACTION 1.5Å
e2afwA1[A:33-361]
nonrep
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Glutaminyl-peptide cyclotransferase ; ligands: AHN,SO4,ZN ; X-RAY DIFFRACTION 1.56Å
e2ek9A2[A:5-64,A:199-416]
nonrep
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Pymol
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AMINOPEPTIDASE ; ligands: BES,IPA,ZN ; X-RAY DIFFRACTION 1.97Å
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