Structural Tags

  • beta-barrel (1)
    A single beta-sheet that twists and coils upon itself. The barrel structure is usually closed by main-chain hydrogen bonds between the first and last strands of the beta-sheet.
  • greek-key (2)
    A topology of four adjacent antiparallel beta-strands in which some interstrand connections go between beta sheets in beta-barrels or sandwiches. The strands are arranged in a pattern similar to an ornamental pattern which is now called Greek key.
  • meander (3)
    A simple topology of a beta-sheet where any two consecutive strands are adjacent and antiparallel.
  • bundle (4)
    An assemble of alpha-helices each oriented along the same bundle axis.
  • left-handed twist (5)
    An arrangement of alpha-helices in which each helix makes a positive angle to the bundle axis.
  • right-handed twist (6)
    An arrangement of alpha-helices in which each helix makes a negative angle to the bundle axis.
  • folded leaf (7)
    A layer of alpha-helices wrapped around a single hydrophobic core.
  • sandwich (8)
    Two beta-sheets which are usually twisted and pack so that their strands are aligned.
  • array of helices (9)
    An assembly of alpha-helices with a great variation of interaxial angles.
  • up-and-down (10)
    Simple topology for a helical bundle or folded leaf, in which consecutive helices are adjacent and antiparallel; it is approximately equivalent to the meander topology of a beta-sheet.
  • crossover connection (11)
    A connection that links secondary structures at the opposite ends of the structural core and goes across the surface of the domain.
  • jelly-roll (12)
    A variant of Greek key topology with both ends of a sandwich or a barrel fold being crossed by two inter-strand connections.
  • antiparallel beta-sheet (13)
    The strand direction in any two adjacent strands are antiparallel
  • parallel beta-sheet (14)
    All strands are parallel each other.
  • mixed beta-sheet (15)
    At least one strand is parallel to one of its two neighbours and antiparallel to the other.
  • clockwise (16)
    Topological variant of a meander beta-sheet barrel or an up-and-down alpha-helical bundle, defined as the direction, in which the sequential secondary structure elements go around the axis with the first element pointing toward the viewer.
  • anticlockwise (17)
    Topological variant of a meander beta-sheet barrel or an up-and-down alpha-helical bundle, defined as the direction, in which the sequential secondary structure elements go around the axis with the first element pointing toward the viewer.