Term Name:	alpha_helix
Synonyms:	a-helix, helix
Definition:	The helix has 3.6 residues per turn which corresponds to a translation of 1.5 angstroms (= 0.15 nm) along the helical axis. Every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier.
Ontology:	Sequence Ontology [SO:0001117]