A superstructure that contains several of these is found in peridin pigment
A superstructure that contains several of these is found in peridin pigments, and a bundle of four of these structures form a bromodomain. A structure that contains several of these structures between 50-degree turns  is known as the globin fold. These structures have a double minima at 208 and 222 nm on far-UV circular dichroism spectroscopy, and Davydov solitons propagate along them. The introduction of glycine into one of these motifs causes a significant entropy increase, and they appear in the third qudrant of a Ramachandran plot. Occuring due to hydrogen bonding between every fourth amino acid, for 10 points, name this protein secondary structure that often traverses membranes, the alternative to a beta sheet.
A superstructure that contains several of these is found in peridin pigments, and a bundle of four of these structures form a bromodomain.
{Alpha helix}