Figure 18. Contour of density distribution of α-β angle pairs.

The contour of the density distribution of the α-β angle pairs is plotted. The plot is divided into three regions named as most favoured, favoured, and allowed, each containing high 50%, 75%, and 90% of all α-β angle pairs. In addition, the α-β angle pairs sampled from 10 arbitrarily selected proteins are plotted as dots over the contour of the general α-β density distribution. The red triangles represent the α-β angle pairs in α-helices, the blue squares in β-sheets, and the black dots in other type of secondary structures.