Ramachandranplottet

Ramachandranplottet is a graphical representation used in structural biology to assess the conformational angles of amino acids within protein structures. Named after G. N. Ramachandran, who first introduced the Ramachandran plot in 1963, it plots the phi (φ) and psi (ψ) dihedral angles of the amino acid residues, offering a visualization of the sterically allowed regions of backbone conformations.

The plot is a two-dimensional graph with phi angles on the x-axis and psi angles on the y-axis. Each point corresponds to the conformational angles of a specific amino acid residue in a protein structure. The most favored regions on the plot indicate common secondary structures like alpha helices and beta sheets, while less populated regions suggest less common or strained conformations.

Ramachandranplottet is widely used for validating and analyzing protein models, ensuring their stereochemical quality. Regions outside the allowed zones may indicate potential errors or unusual conformations, prompting further investigation.

Modern computational tools incorporate Ramachandran plots as part of structure validation software, such as PROCHECK and MolProbity. These tools help researchers confirm the reliability of predicted and experimentally determined protein structures by providing a clear visual assessment of backbone dihedral angles.

Overall, the Ramachandranplot remains a fundamental tool in structural bioinformatics, facilitating the evaluation of protein structure conformance with known stereochemical constraints.