Ramachandran plot

A Ramachandran diagram of the protein PCNA , a human enzyme from the replication machinery that contains both β-sheets and α-helices ( PDB ID 1AXC). The ψ angles are plotted on the ordinate and the φ angles on the abscissa .

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 .

Dihedral angles φ and ψ, ω in the backbone of a protein

Mathematically, the Ramachandran plot is therefore a representation of a function . ${\displaystyle f:\left[-\pi ,\pi \right[\times \left[-\pi ,\pi \right[\rightarrow \mathbb {R_{{}+{}}} }$

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 .

Web links

• To be able to record data to the regions in a Ramachandran plot (English)

Individual evidence

1. ↑ WHAT IF homepage
2. ↑ PROCHECK homepage
3. ↑ USF - Uppsala Software Factory