A plot used by biologists to display the pairs of angles (ϕ, ψ) that govern the twists in the chain of amino-acids forming a protein. Each pair of angles is represented by a point in a square whose limits, on each axis, correspond to (−180°, 180°).
Chemistry
A plot of the torsion angles w and c for amino acid residues in a protein, where w is the torsion angle about the C–NH bond and c is the torsion angle about the C–CO bond. It is named after the Indian physicist Gopalasamudram Narayana Ramachandran (1922–2001), who developed this type of plot with his colleagues in 1963. It is a very useful way of finding which conformations are possible for amino acid residues in proteins.