Number of residues per turn in alpha-helix

Value 3.6 Amino acids per turn
Organism Generic
Reference Pauling L, Corey RB, Branson HR. The Structure of Proteins: Two Hydrogen-Bonded Helical Configurations of the Polypeptide Chain. Proc Nat Acad Sci USA 1951a 37:205-211.PubMed ID14816373
Comments In Pauling's model there are in fact 3.7 amino acids in each turn of the alpha helix, but today when many crystal structures are available the number is considered to be 3.6.
Entered by Ravit Netzer
ID 111185