Alpha-helix

Definition
noun, plural: alpha helices
A right-handed coiled conformation common in many proteins in which the resulting structure resembles a spring or helix.
Supplement
Proteins having an alpha helix conformation are arranged in a way that every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acids four residues earlier, and that all side chains point towards the outside.
Related forms: Pauling-Corey-Branson alpha helix, α-helix.
Compare: beta barrel.

See also: transmembrane protein.