Definition of alpha helix in US English:

alpha helix

noun

Biochemistry
  • One of the two common conformations of the secondary structure of proteins, in which the polypeptide chain assumes the form of a straight, tightly coiled helix, stabilized by hydrogen bonding between carbonyl and amide groups in the peptide linkages of the chain.

Origin

1950s; earliest use found in Linus Pauling (1901–1994), chemist and biochemist.