Backbone
    Alpha 1, Alpha 2,
    Disulfide bond.
    ( end view)
    ( side view)
    ( show peptide backbone )

Secondary structure backbone
    Alpha Helix,
    Beta Strand,
    Turn, Other.
    ( end view)
    ( side view)
    ( show spacefilled peptide,
          backbone atoms,
          sidechain atoms. )
    ( spacefill)
    (slab on off )
    ( show water)