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X - Possible homology level

H - Homology level

T - Topology level

F - Family level

* - Provisional representative

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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

X: Flavodoxin-like
H: Rossmann-like domain in Ribosomal protein L1
T: Rossmann-like domain in Ribosomal protein L1
F: Ribosomal_L1

PF00687

Representatives:

e1ad2A2[A:68-159] nonrep Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

RIBOSOMAL PROTEIN L1 ; ligands: MRD,SO4 ; X-RAY DIFFRACTION 1.8Å

e1i2aA2[A:53-148] nonrep Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S RIBOSOMAL PROTEIN L1P ; X-RAY DIFFRACTION 1.825Å

e1mzpA2[A:58-153] nonrep Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S RIBOSOMAL PROTEIN L1P ; ligands: MG ; X-RAY DIFFRACTION 2.65Å

e1cjsA2[A:52-147] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S RIBOSOMAL PROTEIN L1P ; X-RAY DIFFRACTION 2.300Å

e1dwuB2[B:52-147] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

RIBOSOMAL PROTEIN L1 ; X-RAY DIFFRACTION 2.680Å

e1u63A2[A:52-147] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 3.4Å

e1u63C2[C:52-147] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 3.4Å

e1dwuA2[A:52-147] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

RIBOSOMAL PROTEIN L1 ; X-RAY DIFFRACTION 2.680Å

e3e1bZ2[Z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3izsA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3izrA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j21A2[A:54-150] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vor72[7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e2noqG2[G:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S RIBOSOMAL PROTEIN L1 ; ELECTRON MICROSCOPY 7.3Å

e3zf7J2[J:54-149] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j39z2[z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j3bz2[z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1s1iA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vou72[7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vow72[7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1voy72[7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vp072[7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e2zkr52[5:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3e1dZ2[Z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3jywA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1pnu52[5:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1pny52[5:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j44A2[A:54-150] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j61z2[z:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j65A2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3o58A3[A:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j0oB3[B:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein L10a ; ELECTRON MICROSCOPY

e3j0pB3[B:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein L10a ; ELECTRON MICROSCOPY

e3j0qB3[B:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein L10a ; ELECTRON MICROSCOPY

e3o5hA3[A:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j0lB3[B:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein L10a ; ELECTRON MICROSCOPY

e4cuwt1[t:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vw8A2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vwuA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vx1z1[z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4lq4A2[A:52-147] Image Pymol Jmol Links: PDB, SCOP, CATHDOI

50S RIBOSOMAL PROTEIN L1 ; ligands: CL,IPA ; X-RAY DIFFRACTION 1.75Å

e4cxdu2[u:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4upxu2[u:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4uq1u2[u:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vxvA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e1vxyA2[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e4w27z1[z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH Obsolete PDB

e3j6xL11[L1:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e3j6yL11[L1:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e3j77L11[L1:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e3j78L11[L1:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e3j7rz1[z:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein uL1 ; ELECTRON MICROSCOPY

e4ujcBu2[Bu:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S RIBOSOMAL PROTEIN L10A ; ELECTRON MICROSCOPY

e4ujdAu2[Au:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S RIBOSOMAL PROTEIN L10A ; ELECTRON MICROSCOPY

e4ujeCu2[Cu:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S RIBOSOMAL PROTEIN L10A ; ELECTRON MICROSCOPY

e4v49B52[B5:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 8.7Å

e4v4aB52[B5:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 9.5Å

e4v4bBA1[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e4v4gB72[B7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 11.5Å

e4v4gD72[D7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 11.5Å

e4v4gF72[F7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 11.5Å

e4v4gH72[H7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 11.5Å

e4v4gJ72[J7:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; X-RAY DIFFRACTION 11.5Å

e4v4nAA1[AA:54-150] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; ELECTRON MICROSCOPY

e4v5zB52[B5:51-146] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S Ribosomal protein L10a ; ELECTRON MICROSCOPY

e4v65BZ1[BZ:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH

50S ribosomal protein L1P ; ELECTRON MICROSCOPY

e4v66BZ1[BZ:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH

50S ribosomal protein L1P ; ELECTRON MICROSCOPY

e4v6iBA1[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein rpL1 (L1p) ; ELECTRON MICROSCOPY

e4v6uBA1[BA:54-150] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

50S ribosomal protein L1P ; ELECTRON MICROSCOPY

e4v6wCz2[Cz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a-2 ; ELECTRON MICROSCOPY

e4v6xCz1[Cz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e4v7eCz2[Cz:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e4v7fA1[A:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e4v7hBA1[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; ELECTRON MICROSCOPY

e4v7rBA1[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; X-RAY DIFFRACTION 4Å

e4v7rDA1[DA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1 ; X-RAY DIFFRACTION 4Å

e4v8mBJ2[BJ:54-149] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

RIBOSOMAL PROTEIN ; ELECTRON MICROSCOPY

e4v91t1[t:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

UL1 ; ELECTRON MICROSCOPY

e4v3pLA1[LA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e5aj0Au1[Au:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e4ug0Lz1[Lz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S RIBOSOMAL PROTEIN L10A ; ELECTRON MICROSCOPY

e5fl8I2[I:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH

e5it7qq1[qq:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e5juoE1[E:64-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 (yeast L1) ; ELECTRON MICROSCOPY

e5jupE1[E:64-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 (yeast L1) ; ELECTRON MICROSCOPY

e5jusE1[E:64-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 (yeast L1) ; ELECTRON MICROSCOPY

e5jutE1[E:64-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 (yeast L1) ; ELECTRON MICROSCOPY

e5juuE1[E:64-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 (yeast L1) ; ELECTRON MICROSCOPY

e5jcsI2[I:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e5t2cl1[l:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e5wyjU52[U5:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosome biogenesis protein UTP30 ; ELECTRON MICROSCOPY

e5wykU51[U5:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosome biogenesis protein UTP30 ; ELECTRON MICROSCOPY

e5lksLz1[Lz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e5wlcSN2[SN:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Utp30 ; ELECTRON MICROSCOPY

e5ydtU51[U5:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosome biogenesis protein UTP30 ; ELECTRON MICROSCOPY

e5yduA2[A:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosome biogenesis protein UTP30 ; ligands: PO4 ; X-RAY DIFFRACTION 2.646Å

e5yduB1[B:64-178] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosome biogenesis protein UTP30 ; X-RAY DIFFRACTION 2.646Å

e6em3K2[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6em5K1[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6ek0Lz2[Lz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH

e6elzK2[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6em1K1[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6em4K2[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6c0fK1[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6cb1K1[K:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e5z3gH1[H:106-233] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Proteasome-interacting protein CIC1 ; ELECTRON MICROSCOPY

e6d90K2[K:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6d9jK2[K:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6gqbBA2[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e6gqvBA1[BA:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e6hcfu32[u3:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6hcjw32[w3:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6hcmu32[u3:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e6hcqw31[w3:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e6mtbu1[u:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e6mtcu1[u:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e6mtdu1[u:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6gz3Au2[Au:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e6gz4Au1[Au:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

ribosomal protein uL1 ; ELECTRON MICROSCOPY

e6gz5Au1[Au:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

ribosomal protein uL1 ; ELECTRON MICROSCOPY

e6qzpLz2[Lz:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e6ip52l1[2l:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e6olgAu2[Au:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L10a ; ELECTRON MICROSCOPY

e6r84L1[L:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e6r87L2[L:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e6r86L1[L:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

60S ribosomal protein L1-A ; ELECTRON MICROSCOPY

e6p5iAK1[AK:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6p5nAK1[AK:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6p5jAK1[AK:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6p5kAK1[AK:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

uL1 ; ELECTRON MICROSCOPY

e6sgcB2[B:58-153] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

e6uz7Bq2[Bq:57-152] Image Pymol Jmol Links: PDB, SCOP, CATH, PubMed, DOI

Ribosomal protein ; ELECTRON MICROSCOPY

F: Unmapped domains

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