The document summarizes the Ramachandran plot, which is a plot of the phi and psi dihedral angles of amino acid residues in protein structures. It was originally developed in 1963 to show possible conformations of phi and psi angles for amino acid residues and the empirical distribution of these angles observed in protein structures. The plot takes advantage of the circular nature of dihedral angles, with edges wrapping from right to left and bottom to top. It can be used to determine amino acid preferences and how the presence or absence of groups like a methylene group at C-beta affect the angles.

1. Ramachandran Plot
Dr. Ema SushanMinj
Department of Microbiology

2. Introduction
• Ramachandran Plot is also called as Rama Plot ,Ramachandran diagram and ψφ
Plot.
• It was originally developedin 1963 by G.N. Ramachandran, C.
Ramakrishnan and V. Sasisekharan.
• It is a plot between psi and phi
ψ (Psi) shows the dihedral plot
φ (Phi) shows amino acid residues
• The ω angles of peptide bond is normally 180°, since the partial -double bonds
character keeps the peptide planar.
• Because the dihedral values are circular and 0° is same as 360° , the edges of the
Ramachandran Plot "wrap" Right to left and bottom to top.

5. Uses
 Showing conformations of psi and phi angles are possible for
amino acid residues in a protein.
 Empirical distribution of datapoints observedin a single
structure.
Amino acid preference
• The effect of side chain is small.
• The major effect seen is that of the presence or absence of the
methylene group at C- beta.
• Ex. Glycine has only a hydrogen atom for its side chain possess
smaller van der Waals radius than CH3, CH2 or CH group (starts the
side chain of all other amino acid)

7. Thank you