alpha helix

(redirected from 3.613 helix)
Also found in: Dictionary, Medical, Wikipedia.

alpha helix

[′al·fə ′hē·liks]
(cell and molecular biology)
A spatial configuration of the polypeptide chains of proteins in which the chain assumes a helical form, 0.54 nanometer in pitch, 3.6 amino acids per turn, presenting the appearance of a hollow cylinder with radiating side groups.