Why is it called alpha helix?
Reason for the name of alpha-helices:
Amino acid chains frequently take the shape of an alpha helix. The fibrous protein alpha keratin is known to be the source of alpha-helices. Two alpha helices are twisted around each other in a coiled-coil structure in this protein. Many proteins have a coiled structural arrangement that is made up of a single chain of amino acids that is held together by hydrogen bonds.