Describe some of the features of an α helix.
The α helix is coil stabilized by intrachain hydrogen bonds between the carbonyl oxygen of a residue and the amide hydrogen of the fourth residue away. There are 3.6 amino acids per turn. The hydrogen bonds are between amino acid residues that have two intervening residues. Thus, these amino acid residues are found on the same side of the coil. The helix is almost always right-handed, although left-handed helices are, in theory, possible.