Ramchandran plot / Ramachandran diagram / Ø, ψ plot

Developed by: G.N. Ramachandran in 1963

1. + and –
2. + and +
3. – and –
4. 0

White regions: sterically disallowed for all amino acids except glycine

Red regions: allowed regions namely the alpha-helical and beta-helical conformations

Yellow areas: outer limit

Exception: Glycine can lie anywhere