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helix Definition

he·lix (hē′liks)

noun pl. he′·lixes or hel′i·ces′hel′i sēz′

  1. any spiral, as one lying in a single plane or, esp., one moving around a right circular cone or cylinder at a constant angle, as a screw or bolt thread does
  2. Anat. the folded rim of cartilage around the outer ear
  3. Archit. an ornamental spiral, as a volute on a Corinthian or Ionic capital
  4. Zool. any of a genus (Helix) of spiral-shelled land gastropods, including the common, edible European snail (H. pomatia)

Etymology: L, kind of ivy, spiral < Gr, a spiral < helissein, to turn around < IE base *wel-, to turn, twist > walk

helix Usage Examples

Converse of object

  • predict: A hidden Markov model for predicting transmembrane helices in protein sequences.
  • represent: One real use might be to use ' ribbon ' to represent helices in proteins.
  • contain: The Example The tutorial shows that the crystal structure of: contains an approximate 3-fold helix.
  • form: DNA molecules have two distinct strands which are held together by weak hydrogen bonds to form a double helix.

Adjective modifier

  • TM: Additionally the methods were examined for how well they predict the exact start and end of TM helices.
  • amphipathic: This family contains the paired amphipathic helix ( PAH ) repeat.
  • transmembrane: The positions of the transmembrane helices of the core dimer are based on Fig.
  • right-handed: Each strand is a left-handed helix twisted on itself, but the three strands are twisted into a larger right-handed triple helix.
  • left-handed: The clincher was the fact that the electron density maps revealed perfect left-handed helices.
  • triple: The molecule consists of a short triple helix about 105 nm in length with a large globular domain at each end.

Modifies a noun

  • bundle: Both models are composed of a left-handed helix bundle.
  • axis: Also the planes of the base residues are perpendicular to the helix axis.
  • angle: The choice of helix angle, which is influenced by the type of machine used to cut the gears, is discussed.
  • rod: This tells the coil command to use the coordinates for the helix rod axis rather than the actual CA coordinates.
  • structure: The double helix structure of DNA became a design icon.

Noun used with modifier

  • transmembrane: Such movements would modulate tension on the ends of transmembrane helices to promote channel opening or closing.
  • alpha: These two bonds act to stop the alpha helix forming.
  • DNA: Then the marvelous rising spiral traverse like climbing a double DNA helix around it an insane position on the overhanging North face.
  • recognition: The effect of the bound l-tryptophan molecules is to orient the recognition helices correctly for DNA binding.
  • turn: The dish feed is based on a small 4 turn helix mounted on a die cast aluminum box of 50mm x 50mm.