Ramachandran outlier

A Ramachandran Plot described on 1963 by Ramachandran, G.N.; Ramakrishnan, C.; Sasisekharan, V. ^[1]

Ramachandran outlier are those aminoacids with non favorable dihedral angles, and Ramachandran plot is a powerful tool for making those evident. Most of the times, Ramachandran outliers are a consequence of mistakes during the data processing.

However, sometimes, Ramachandran outliers might play a special role in the structure function. See for example the structure