Ramachandran plot
A Ramachandran plot (Ramachandran and Chart) is a chart showing the statistical distribution of combinations of two dihedral angles (φ and ψ) of a particular protein - backbones represents. It is named after the Indian scientist GN Ramachandran .
![](https://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Protein_backbone_PhiPsiOmega_drawing.jpg/130px-Protein_backbone_PhiPsiOmega_drawing.jpg)
Mathematically, the Ramachandran plot is therefore a representation of a function .
Ramachandran plot s are for respective specific types of protein - molecules characteristic. A Ramachandran plot can also be used to estimate the frequency of α-helices , β-sheets and other protein secondary structures in the molecule.
The Ramachandran plot (an important module in computer programs that automatically the quality of structural provisions crystal structure analysis , nuclear magnetic resonance spectroscopy , etc.) check for proteins, for example in WHATIF, PROCHECK or USF. Alternatively, a Janin plot can be used.
literature
- GN Ramachandran, C. Ramakrishnan and V. Sasisekharan (1963): Stereochemistry of polypeptide chain configurations. In: J. Mol. Biol. Vol. 7, pp. 95-99, PMID 13990617 .