• internal structural duplication (1)
    Presence or two or more structural units within the protein or protein region corresponding to family or superfamily domain.
  • segment-swapping (2)
    Exchange of equivalent core secondary structural elements between constituent subunits in homo-oligomeric complexes. The swapped elements in the homo-oligomer have an environment essentially identical to that in the monomer.
  • fragment (partial coverage) (3)
    Protein construct that is shorter than the region characteristic of the protein domain.
  • circular permutation (4)
    Change of the sequential order of the N- and C-terminal parts in protein structures that does not affect their relative spatial arrangement. It can be visualized through ligation of the termini and cleavage at another site to produce new termini.
  • topoisomer (5)
    Protein structures adopting similar folds with the same architecture and topology but different entanglement of equivalent connecting loops.
  • structural flexibility (6)
    Conformational changes due to movement of protein backbone or side-chain atoms at the time scale of structure determination experiment.
  • non-compact subunit (7)
    A polypeptide chain that doesn't fold upon itself but forms a part of globular oligomeric structure.
  • loop crossing (8)
    Connection between secondary structural elements that cross each other.
  • chameleon part(s) (9)
    String of amino acid residues shown to adopt different secondary structures in proteins.
  • independent duplication event (10)
    Structural units that have resulted from independent duplication events.
  • asymmetric oligomer (11)
    Oligomeric complex in which individual subunits have distinct conformations.
  • metamorph (12)
    Proteins existing in two or more different conformational states in native conditions. The transition between these conformations involves a large rearrangement of hydrogen bonding network and many of the packing interactions.
  • fragment (family coverage) (13)
    Protein construct that is shorter than the full-length protein but corresponds to the entire protein family domain.
  • fragment (multi-family coverage) (14)
    Protein construct that is shorter than the full-length protein but corresponds to two or more protein family domains.
  • conformational change (15)
    Any change in the three-dimensional structure of a macromolecule.
  • chimera (16)
    An engineered protein that contains parts of different natural sequences
  • fold decay (17)
    A deletion event that affects the protein common fold.
  • structural genomics target (18)
    Protein structure determined by Protein Structure Initiative
  • strand flip (19)
    Change of the orientation of the strand with respect to the core elements.
  • alternative fold (20)
    representative structure which is different to the common fold of the parental node
  • two-repeat structure (21)
    experimental structure that contains two tandemly repeated units
  • three-repeat structure (22)
    experimental structure that contains three tandemly repeated units
  • four-repeat structure (23)
    experimental structure that contains four tandemly repeated units
  • five(+)-repeat structure (24)
    experimental structure that contains five or more tandemly repeated units
  • obligatory oligomeric unit (25)
    globular unit made of two or more protein chains, which are not compact on their own but complement each other to a compact domain
  • inconsistent topology (26)
    topology that is not observed in other related protein structures and it may be an experimental artifact